107-401: American sweetgum ( Liquidambar styraciflua ), also known as American storax , hazel pine , bilsted , redgum , satin-walnut , star-leaved gum , alligatorwood , gumball tree , or simply sweetgum , is a deciduous tree in the genus Liquidambar native to warm temperate areas of eastern North America and tropical montane regions of Mexico and Central America . Sweetgum is one of
214-399: A behavior known as " marcescence " whereby dead leaves are not shed in the fall and remain on the tree until being blown off by the weather. This is caused by incomplete development of the abscission layer. It is mainly seen in the seedling and sapling stage, although mature trees may have marcescence of leaves on the lower branches. A number of deciduous plants remove nitrogen and carbon from
321-408: A decussate pattern, in which each node rotates by 1/4 (90°) as in the herb basil . The leaves of tricussate plants such as Nerium oleander form a triple helix. The leaves of some plants do not form helices. In some plants, the divergence angle changes as the plant grows. In orixate phyllotaxis, named after Orixa japonica , the divergence angle is not constant. Instead, it is periodic and follows
428-602: A greater rate of transpiration (and hence CO 2 uptake as this occurs when stomata are open) during the summer growth period. The deciduous characteristic has developed repeatedly among woody plants. Trees include maple , many oaks and nothofagus , elm , beech , aspen , and birch , among others, as well as a number of coniferous genera , such as larch and Metasequoia . Deciduous shrubs include honeysuckle , viburnum , and many others. Most temperate woody vines are also deciduous, including grapes , poison ivy , Virginia creeper , wisteria , etc. The characteristic
535-544: A grove of sweetgum trees to the Flight 93 Memorial in Shanksville, Pennsylvania. The imperfect fungus Dicarpella dryina Sutton is a leaf parasite reported to occur on a wide range of host plants, including species of sweetgum ( Liquidambar styraciflua L. ). Limber and Cash reported that leaf spots produced by this pathogen on several different genera of forest trees were 2–5 mm diameter with regular margins. During
642-425: A patchwork of leafy and leafless trees. Leaf A leaf ( pl. : leaves ) is a principal appendage of the stem of a vascular plant , usually borne laterally above ground and specialized for photosynthesis . Leaves are collectively called foliage , as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue
749-504: A petiole like structure. Pseudopetioles occur in some monocotyledons including bananas , palms and bamboos . Stipules may be conspicuous (e.g. beans and roses ), soon falling or otherwise not obvious as in Moraceae or absent altogether as in the Magnoliaceae . A petiole may be absent (apetiolate), or the blade may not be laminar (flattened). The petiole mechanically links the leaf to
856-463: A plant matures; as a case in point Eucalyptus species commonly have isobilateral, pendent leaves when mature and dominating their neighbors; however, such trees tend to have erect or horizontal dorsiventral leaves as seedlings, when their growth is limited by the available light. Other factors include the need to balance water loss at high temperature and low humidity against the need to absorb atmospheric carbon dioxide. In most plants, leaves also are
963-544: A popular landscaping and street tree. Three varieties, Palo Alto , Festival , and Burgundy , introduced in the late 1950s by the Saratoga Horticultural Foundation in Palo Alto, California became popular in the urban landscapes of California because of their pleasing appearance, striking fall colors, and ability to grow quickly and thrive; however, as the trees matured, the damage caused by surface roots and
1070-419: A regular organization at the cellular scale. Specialized cells that differ markedly from surrounding cells, and which often synthesize specialized products such as crystals, are termed idioblasts . The epidermis is the outer layer of cells covering the leaf. It is covered with a waxy cuticle which is impermeable to liquid water and water vapor and forms the boundary separating the plant's inner cells from
1177-686: A resinous fragrance. While the starry five-pointed leaves of Liquidambar resemble those of some maples ( Acer ), Liquidambar is easily distinguished from Acer by its glossy, leathery leaves that are positioned singly ( alternate ), not in pairs (opposite) on the stems. Luna and promethea moth caterpillars feed on the leaves. The flowers typically appear in spring and persist into autumn/fall, sometimes persisting into winter. They are typically about 25–40 mm (1– 1 + 1 ⁄ 2 in) in diameter and are covered with rusty hairs. The flowers are unisexual and greenish in color. Staminate flowers in terminal racemes 5–8 cm (2–3 in) long,
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#17330861398711284-475: A scaffolding matrix imparting mechanical rigidity to leaves. Leaves are normally extensively vascularized and typically have networks of vascular bundles containing xylem , which supplies water for photosynthesis , and phloem , which transports the sugars produced by photosynthesis. Many leaves are covered in trichomes (small hairs) which have diverse structures and functions. The major tissue systems present are These three tissue systems typically form
1391-541: A severe dry season, some plants may shed their leaves until the dry season ends. In either case, the shed leaves may be expected to contribute their retained nutrients to the soil where they fall. In contrast, many other non-seasonal plants, such as palms and conifers, retain their leaves for long periods; Welwitschia retains its two main leaves throughout a lifetime that may exceed a thousand years. The leaf-like organs of bryophytes (e.g., mosses and liverworts ), known as phyllids , differ heavily morphologically from
1498-402: A single (sometimes more) primary vein in the centre of the leaf, referred to as the midrib or costa, which is continuous with the vasculature of the petiole. The secondary veins, also known as second order veins or lateral veins, branch off from the midrib and extend toward the leaf margins. These often terminate in a hydathode , a secretory organ, at the margin. In turn, smaller veins branch from
1605-573: A single leaf grows from each node, and when the stem is held straight, the leaves form a helix . The divergence angle is often represented as a fraction of a full rotation around the stem. A rotation fraction of 1/2 (a divergence angle of 180°) produces an alternate arrangement, such as in Gasteria or the fan-aloe Kumara plicatilis . Rotation fractions of 1/3 (divergence angles of 120°) occur in beech and hazel . Oak and apricot rotate by 2/5, sunflowers, poplar, and pear by 3/8, and in willow and almond
1712-523: A single point. In evolutionary terms, early emerging taxa tend to have dichotomous branching with reticulate systems emerging later. Veins appeared in the Permian period (299–252 mya), prior to the appearance of angiosperms in the Triassic (252–201 mya), during which vein hierarchy appeared enabling higher function, larger leaf size and adaption to a wider variety of climatic conditions. Although it
1819-409: A small leaf. Stipules may be lasting and not be shed (a stipulate leaf, such as in roses and beans ), or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf). The situation, arrangement, and structure of the stipules is called the "stipulation". Veins (sometimes referred to as nerves) constitute one of the most visible features of leaves. The veins in a leaf represent
1926-405: A specialized cell group known as the stomatal complex. The opening and closing of the stomatal aperture is controlled by the stomatal complex and regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Stomata therefore play the important role in allowing photosynthesis without letting the leaf dry out. In a typical leaf, the stomata are more numerous over
2033-483: A variety of patterns (venation) and form cylindrical bundles, usually lying in the median plane of the mesophyll , between the two layers of epidermis . This pattern is often specific to taxa, and of which angiosperms possess two main types, parallel and reticulate (net like). In general, parallel venation is typical of monocots, while reticulate is more typical of eudicots and magnoliids (" dicots "), though there are many exceptions. The vein or veins entering
2140-554: A variety of plants including sweetgum. They may prevent pathogen invasion by inhibiting fungal enzyme activity. Although cells of healthy sweetgum tissue appear rich in tannins, these materials apparently were not effective in preventing fungal colonization by D. dryina . Deciduous In the fields of horticulture and botany , the term deciduous ( / d ɪ ˈ s ɪ dʒ u . ə s / ) means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves , usually in
2247-598: Is a deciduous woody shrub found in Japan . Forests where a majority of the trees lose their foliage at the end of the typical growing season are called deciduous forests. These forests are found in many areas worldwide and have distinctive ecosystems, understory growth, and soil dynamics. Two distinctive types of deciduous forests are found growing around the world. Temperate deciduous forest biomes are plant communities distributed in North and South America, Asia, Southern slopes of
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#17330861398712354-509: Is a light brown tinged with red and sometimes gray with dark streaks and has a density of 590 kg/m (37 lb/cu ft). It is deeply fissured with scaly ridges. The branches carry layers of cork. The branchlets are pithy, many-angled, winged, and at first covered with rusty hairs, finally becoming red brown, gray or dark brown. As an ornamental tree, the species has a drawback—the branches may have ridges or "wings" that cause more surface area, increasing weight of snow and ice accumulation on
2461-500: Is also found in Miocene deposits of the Tertiary of Europe. Liquidambar styraciflua is a medium-sized to large tree, growing anywhere from 15–20 m (50–70 ft) in cultivation and up to 45 m (150 ft) in the wild, with a trunk up 60–90 cm (2–3 ft) in diameter, on average. Trees may live to 400 years. The tree is a symmetrical shape and crowns into an egg shape when
2568-584: Is also used for veneer for plywood . The wood is very compact and fine-grained, the heartwood being reddish, and, when cut into planks, marked transversely with blackish belts. Sweetgum is used principally for lumber, veneer, plywood, slack cooperage, fuel, and pulpwood. The lumber is made into boxes and crates, furniture, cabinets for radios, televisions, and phonographs, interior trim, and millwork . The veneer and plywood, (typically backed with some other kind of wood which shrinks and warps less) are used for boxes, pallets, crates, baskets, and interior woodwork. It
2675-637: Is banned in some places for this reason. In abundance, they can leave a lawn lumpy. The winter buds are yellow brown, 6 mm ( 1 ⁄ 4 in) long, acute. The inner scales enlarge with the growing shoot, becoming 13 mm ( 1 ⁄ 2 in) long, green tipped with red. Sweetgum is one of the most common hardwoods in the southeastern and Mid-Atlantic United States , where it occurs naturally in lowlands from southwestern Connecticut south to central Florida , through central Ohio and west to Illinois , southern Missouri , and eastern Texas , but not colder highland areas of Appalachia or
2782-501: Is called Styrax liquida . However, the first mention of any use of the amber is described by Juan de Grijalva, the nephew of the governor of Cuba, in the year 1517. Juan de Grijalva tells of gift exchanges with the Mayas "who presented them with, among other things, hollow reeds of about a span long filled with dried herbs and sweet-smelling liquid amber which, when lighted in the way shown by the natives, diffused an agreeable odour." The species
2889-455: Is called a stipe in ferns . The lamina is the expanded, flat component of the leaf which contains the chloroplasts . The sheath is a structure, typically at the base that fully or partially clasps the stem above the node, where the leaf is attached. Leaf sheathes typically occur in Poaceae (grasses) and Apiaceae (umbellifers). Between the sheath and the lamina, there may be a pseudopetiole ,
2996-700: Is completed (marked by the transition from bright green spring leaves to dark green summer ones) the chlorophyll level in the leaves remains stable until cool temperatures arrive in autumn. When autumn arrives and the days are shorter or when plants are drought-stressed, the chlorophyll steadily breaks down, allowing other pigments present in the leaf to become apparent and resulting in non-green colored foliage. The brightest leaf colors are produced when days grow short and nights are cool, but remain above freezing. These other pigments include carotenoids that are yellow, brown, and orange. Anthocyanin pigments produce red and purple colors, though they are not always present in
3103-400: Is formed between the leaf petiole and the stem. This layer is formed in the spring during active new growth of the leaf; it consists of layers of cells that can separate from each other. The cells are sensitive to a plant hormone called auxin that is produced by the leaf and other parts of the plant. When auxin coming from the leaf is produced at a rate consistent with that from the body of
3210-427: Is hard, dry, and globose, 25–40 mm (1– 1 + 1 ⁄ 2 in) in diameter, composed of numerous (40–60) capsules . Each capsule, containing one to two small seeds , has a pair of terminal spikes (for a total of 80–120 spikes). When the fruit opens and the seeds are released, each capsule is associated with a small hole (40–60 of these) in the compound fruit. Fallen, opened fruits are often abundant beneath
3317-588: Is low. Also, the American sweetgum tree does not grow well in shady areas. Grown as an ornamental tree in Australia, Liquidambar styraciflua has a distribution on mainland Australia from southwestern Western Australia , southern South Australia , New South Wales , Victoria , and all the way up to the Atherton Tablelands in far North Queensland . During the late 1970s and throughout the 1980s, Sweetgums were
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3424-442: Is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus , palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper ( adaxial ) and lower ( abaxial ) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases),
3531-406: Is the more complex pattern, branching veins appear to be plesiomorphic and in some form were present in ancient seed plants as long as 250 million years ago. A pseudo-reticulate venation that is actually a highly modified penniparallel one is an autapomorphy of some Melanthiaceae , which are monocots; e.g., Paris quadrifolia (True-lover's Knot). In leaves with reticulate venation, veins form
3638-522: Is useful in plant identification; for instance in parts of Southern California and the American Southeast , deciduous and evergreen oak species may grow side by side. Periods of leaf fall often coincide with seasons: winter in the case of cool-climate plants or the dry-season in the case of tropical plants, however there are no deciduous species among tree-like monocotyledonous plants, e.g. palms , yuccas , and dracaenas . The hydrangea hirta
3745-605: The Midwestern states . The species also occurs in Mexico from southern Nuevo León south to Chiapas , as well as in Guatemala , El Salvador , Belize , Nicaragua and Honduras . In Mexico and Central America , it is a characteristic plant of cloud forests , growing at middle elevations in various mountainous areas where the climate is humid and more temperate. The US government distribution maps for this species are incorrect concerning
3852-553: The autumn ; to the shedding of petals , after flowering; and to the shedding of ripe fruit . The antonym of deciduous in the botanical sense is evergreen . Generally, the term "deciduous" means "the dropping of a part that is no longer needed or useful" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer , deciduous teeth (baby teeth) in some mammals (including humans); or decidua ,
3959-494: The diet of many animals . Correspondingly, leaves represent heavy investment on the part of the plants bearing them, and their retention or disposition are the subject of elaborate strategies for dealing with pest pressures, seasonal conditions, and protective measures such as the growth of thorns and the production of phytoliths , lignins , tannins and poisons . Deciduous plants in frigid or cold temperate regions typically shed their leaves in autumn, whereas in areas with
4066-456: The dry season or other seasons, depending on variations in rainfall . The converse of deciduous is evergreen , where foliage is shed on a different schedule from deciduous plants, therefore appearing to remain green year round because not all the leaves are shed at the same time. Plants that are intermediate may be called semi-deciduous ; they lose old foliage as new growth begins. Other plants are semi-evergreen and lose their leaves before
4173-503: The foliage before they are shed and store them in the form of proteins in the vacuoles of parenchyma cells in the roots and the inner bark. In the spring, these proteins are used as a nitrogen source during the growth of new leaves or flowers. Plants with deciduous foliage have advantages and disadvantages compared to plants with evergreen foliage. Since deciduous plants lose their leaves to conserve water or to better survive winter weather conditions, they must regrow new foliage during
4280-424: The gymnosperms and angiosperms . Euphylls are also referred to as macrophylls or megaphylls (large leaves). A structurally complete leaf of an angiosperm consists of a petiole (leaf stalk), a lamina (leaf blade), stipules (small structures located to either side of the base of the petiole) and a sheath. Not every species produces leaves with all of these structural components. The proximal stalk or petiole
4387-500: The heartwood ; it is heavy, straight, satiny, and close-grained, but not strong. It takes a beautiful polish, but warps badly in drying. The wood has a specific gravity of 0.5910. It is too liable to decay for outdoor use. In the carpentry industry, the timber is referred to as satin walnut and is one of the most important materials for plywood manufacturers. It is used for furniture, interior trim, railroad ties , cigar boxes , crates, flooring , barrels, woodenware, and wood pulp. It
Liquidambar styraciflua - Misplaced Pages Continue
4494-551: The phyllids of mosses and liverworts . Leaves are the most important organs of most vascular plants. Green plants are autotrophic , meaning that they do not obtain food from other living things but instead create their own food by photosynthesis . They capture the energy in sunlight and use it to make simple sugars , such as glucose and sucrose , from carbon dioxide and water. The sugars are then stored as starch , further processed by chemical synthesis into more complex organic molecules such as proteins or cellulose ,
4601-399: The plant shoots and roots . Vascular plants transport sucrose in a special tissue called the phloem . The phloem and xylem are parallel to each other, but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch (ramify) to form veins which supply as much of the leaf as possible, ensuring that cells carrying out photosynthesis are close to
4708-834: The Himalayas, Europe and for cultivation purposes in Oceania. They have formed under climatic conditions which have great seasonable temperature variability. Growth occurs during warm summers, leaf drop in autumn, and dormancy during cold winters. These seasonally distinctive communities have diverse life forms that are impacted greatly by the seasonality of their climate, mainly temperature and precipitation rates. These varying and regionally different ecological conditions produce distinctive forest plant communities in different regions. Tropical and subtropical deciduous forest biomes have developed in response not to seasonal temperature variations but to seasonal rainfall patterns. During prolonged dry periods
4815-490: The amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the sun . A leaf with lighter-colored or white patches or edges is called a variegated leaf . Leaves can have many different shapes, sizes, textures and colors. The broad, flat leaves with complex venation of flowering plants are known as megaphylls and
4922-679: The amount of light they absorb to avoid or mitigate excessive heat, ultraviolet damage, or desiccation, or to sacrifice light-absorption efficiency in favor of protection from herbivory. For xerophytes the major constraint is not light flux or intensity , but drought. Some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides . Leaves also function to store chemical energy and water (especially in succulents ) and may become specialized organs serving other functions, such as tendrils of peas and other legumes,
5029-411: The autumn. This autumnal coloring has been characterized as not simply a flame, but a conflagration. Its reds and yellows compare to those of the maples ( Acer ), and in addition it has the dark purples and smoky browns of the ash ( Fraxinus ). However, in the northern part of its range, and where planted in yet colder areas, the leaves are often killed by frost while still green. On the other hand, in
5136-418: The bark of the tree when wounded. It has many names, including liquid amber or copalm balsam . It is a kind of native balsam, or resin, resembling turpentine . It may be clear, reddish, or yellow, with a pleasant smell like ambergris . As the resin ages, it solidifies, the form in which it was historically exported in barrels. The resin is produced by stripping, boiling, and pressing the tree's bark. The gum
5243-583: The basic structural material in plant cell walls, or metabolized by cellular respiration to provide chemical energy to run cellular processes. The leaves draw water from the ground in the transpiration stream through a vascular conducting system known as xylem and obtain carbon dioxide from the atmosphere by diffusion through openings called stomata in the outer covering layer of the leaf ( epidermis ), while leaves are orientated to maximize their exposure to sunlight. Once sugar has been synthesized, it needs to be transported to areas of active growth such as
5350-452: The blade attaches directly to the stem. Subpetiolate leaves are nearly petiolate or have an extremely short petiole and may appear to be sessile. In clasping or decurrent leaves, the blade partially surrounds the stem. When the leaf base completely surrounds the stem, the leaves are said to be perfoliate , such as in Eupatorium perfoliatum . In peltate leaves, the petiole attaches to
5457-406: The blade inside the blade margin. In some Acacia species, such as the koa tree ( Acacia koa ), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes . There may or may not be normal pinnate leaves at the tip of the phyllode. A stipule , present on the leaves of many dicotyledons , is an appendage on each side at the base of the petiole, resembling
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#17330861398715564-416: The branches get too heavy after its first two years of cultivation. Another distinctive feature of the tree is the peculiar appearance of its small branches and twigs. The bark attaches itself to these in plates edgewise instead of laterally, and a piece of the leafless branch with the aid of a little imagination readily takes on a reptilian form; indeed, the tree is sometimes called "alligatorwood". The bark
5671-606: The city were either damaging or beginning to damage nearby structures. It is now recommended that the trees be planted at least 15 to 20 feet from structures and that they should not be used as street trees. Among the many cultivars of Liquidambar styraciflua are (those marked agm have gained the Royal Horticultural Society 's Award of Garden Merit ): The organizers of the September 11th Memorial in New York donated
5778-661: The disease red leaf spot. Results of this investigation indicate that D. dryina can penetrate leaf tissue directly, thus having the ability to initiate infection on both upper and lower leaf surfaces. In other regions of the U.S., sweetgum populations may not be as susceptible to local populations of this fungus. Environmental stress factors may also be involved, as reports have indicated that herbicide application and chlorosis caused by iron deficiency may increase susceptibility of D. dryina . Tannins (a type of biomolecule found in trees to protect it from fire, insects, and bacteria) have been reported to occur in healthy tissue of
5885-428: The earliest trees to lose their leaves in the fall. In sub-Arctic climates such as Alaska , leaves begin turning colors as early as August. However, for most temperate regions it takes place in late September through early November and in subtropical climates such as the southern US, it may be November into December. Leaf drop or abscission involves complex physiological signals and changes within plants. When leafout
5992-595: The early Devonian lycopsid Baragwanathia , first evolved as enations, extensions of the stem. True leaves or euphylls of larger size and with more complex venation did not become widespread in other groups until the Devonian period , by which time the carbon dioxide concentration in the atmosphere had dropped significantly. This occurred independently in several separate lineages of vascular plants, in progymnosperms like Archaeopteris , in Sphenopsida , ferns and later in
6099-553: The equivalents of the petioles and stipules of leaves. Because each leaflet can appear to be a simple leaf, it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae . The middle vein of a compound leaf or a frond , when it is present, is called a rachis . Leaves which have a petiole (leaf stalk) are said to be petiolate . Sessile (epetiolate) leaves have no petiole and
6206-657: The external world. The cuticle is in some cases thinner on the lower epidermis than on the upper epidermis, and is generally thicker on leaves from dry climates as compared with those from wet climates. The epidermis serves several functions: protection against water loss by way of transpiration , regulation of gas exchange and secretion of metabolic compounds. Most leaves show dorsoventral anatomy: The upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis tissue includes several differentiated cell types; epidermal cells, epidermal hair cells ( trichomes ), cells in
6313-419: The extreme southern or tropical parts of its range, some trees are evergreen or semi-evergreen, with negligible fall color. The leaves are 8–18 cm (3–7 in) broad with glandular serrate teeth. The base is truncate or slightly heart-shaped. They come out of the bud plicate, downy, pale green, when full grown are bright green, smooth, shining above, paler beneath. They contain tannin and when bruised give
6420-677: The fall months and the Western United States as it has more evergreen and fewer deciduous plants, combined with the West Coast and its maritime climate. ( See also : Autumn leaf color ) Most of the Southern Hemisphere lacks deciduous plants due to its milder winters and smaller landmass, most of which is nearer the equator with only far southern South America and the southern island of New Zealand producing distinct fall colors. The beginnings of leaf drop starts when an abscission layer
6527-591: The flowers can be damaged by frost or, in dry season regions, result in water stress on the plant. Spring leafout and fall leaf drop are triggered by a combination of daylight and air temperatures. The exact conditions required will vary with the species, but generally more cold-tolerant genera such as Salix will leaf-out earlier and lose their leaves later, while genera such as Fraxinus and Juglans can only grow in warm, frost-free conditions so they need at least 13 hours of daylight and air temperatures of around 70 °F (21 °C) to leaf out. They will be among
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#17330861398716634-426: The foliage is dropped to conserve water and prevent death from drought. Leaf drop is not seasonally dependent as it is in temperate climates. It can occur any time of year and varies by region of the world. Even within a small local area there can be variations in the timing and duration of leaf drop; different sides of the same mountain and areas that have high water tables or areas along streams and rivers can produce
6741-406: The fraction is 5/13. These arrangements are periodic. The denominator of the rotation fraction indicates the number of leaves in one period, while the numerator indicates the number of complete turns or gyres made in one period. For example: Most divergence angles are related to the sequence of Fibonacci numbers F n . This sequence begins 1, 1, 2, 3, 5, 8, 13; each term is the sum of
6848-866: The ground, they are referred to as prostrate . Perennial plants whose leaves are shed annually are said to have deciduous leaves, while leaves that remain through winter are evergreens . Leaves attached to stems by stalks (known as petioles ) are called petiolate, and if attached directly to the stem with no petiole they are called sessile. Dicot leaves have blades with pinnate venation (where major veins diverge from one large mid-vein and have smaller connecting networks between them). Less commonly, dicot leaf blades may have palmate venation (several large veins diverging from petiole to leaf edges). Finally, some exhibit parallel venation. Monocot leaves in temperate climates usually have narrow blades, and usually parallel venation converging at leaf tips or edges. Some also have pinnate venation. The arrangement of leaves on
6955-417: The humid maritime climate and lower overall species diversity . It is also a factor that the continental United States and southern Canada are at a lower latitude than northern Europe, so the sun during the fall months is higher and stronger. This combination of strong sun and cool temperatures leads to more intense fall colors. The Southern United States also has poor fall colors due to warm temperatures during
7062-414: The increased production of seed balls led to the tree being considered a nuisance and a liability. Thousands of trees would be removed and repairs had to be conducted on nearby structures damaged by roots. The Western Arborist published a study that concluded that Sweetgums accounted for the greatest number of trees causing damage; in the city of Alameda alone it was found that 69% of Liquidambars planted in
7169-443: The leaf from the petiole are called primary or first-order veins. The veins branching from these are secondary or second-order veins. These primary and secondary veins are considered major veins or lower order veins, though some authors include third order. Each subsequent branching is sequentially numbered, and these are the higher order veins, each branching being associated with a narrower vein diameter. In parallel veined leaves,
7276-523: The leaf veins form, and these have functional implications. Of these, angiosperms have the greatest diversity. Within these the major veins function as the support and distribution network for leaves and are correlated with leaf shape. For instance, the parallel venation found in most monocots correlates with their elongated leaf shape and wide leaf base, while reticulate venation is seen in simple entire leaves, while digitate leaves typically have venation in which three or more primary veins diverge radially from
7383-551: The leaves of vascular plants . In most cases, they lack vascular tissue, are only a single cell thick, and have no cuticle , stomata, or internal system of intercellular spaces. (The phyllids of the moss family Polytrichaceae are notable exceptions.) The phyllids of bryophytes are only present on the gametophytes , while in contrast the leaves of vascular plants are only present on the sporophytes . These can further develop into either vegetative or reproductive structures. Simple, vascularized leaves ( microphylls ), such as those of
7490-526: The leaves. Rather, they are produced in the foliage in late summer, when sugars are trapped in the leaves after the process of abscission begins. Parts of the world that have showy displays of bright autumn colors are limited to locations where days become short and nights are cool. The New England region of the United States and southeastern Canada tend to produce particularly good autumn colors for this reason, with Europe producing generally poorer colors due to
7597-483: The main valuable forest trees in the southeastern United States , and is a popular ornamental tree in temperate climates . It is recognizable by the combination of its five-pointed star-shaped leaves (similar to maple leaves) and its hard, spiked fruits. It is currently classified in the plant family Altingiaceae , but was formerly considered a member of the Hamamelidaceae . This plant's genus name Liquidambar
7704-412: The next growing season, retaining some during winter or dry periods. Many deciduous plants flower during the period when they are leafless, as this increases the effectiveness of pollination . The absence of leaves improves wind transmission of pollen for wind-pollinated plants and increases the visibility of the flowers to insects in insect-pollinated plants. This strategy is not without risks, as
7811-783: The next suitable growing season; this uses resources which evergreens do not need to expend. Evergreens suffer greater water loss during the winter and they also can experience greater predation pressure , especially when small. Deciduous trees experience much less branch and trunk breakage from glaze ice storms when leafless, and plants can reduce water loss due to the reduction in availability of liquid water during cold winter days. Losing leaves in winter may reduce damage from insects; repairing leaves and keeping them functional may be more costly than just losing and regrowing them. Removing leaves also reduces cavitation which can damage xylem vessels in plants. This then allows deciduous plants to have xylem vessels with larger diameters and therefore
7918-404: The photosynthetic organelles , the chloroplasts , to light and to increase the absorption of carbon dioxide while at the same time controlling water loss. Their surfaces are waterproofed by the plant cuticle and gas exchange between the mesophyll cells and the atmosphere is controlled by minute (length and width measured in tens of μm) openings called stomata which open or close to regulate
8025-484: The pistillate in a solitary head on a slender peduncle borne in the axil of an upper leaf. Staminate flowers destitute of calyx and corolla, but are surrounded by hairy bracts. Stamens indefinite; filaments short; anthers introrse. Pistillate flowers with a two-celled, two-beaked ovary, the carpels produced into a long, recurved, persistent style. The ovaries all more or less cohere and harden in fruit. There are many ovules but few mature. The distinctive compound fruit
8132-412: The plant and provides the route for transfer of water and sugars to and from the leaf. The lamina is typically the location of the majority of photosynthesis. The upper ( adaxial ) angle between a leaf and a stem is known as the axil of the leaf. It is often the location of a bud . Structures located there are called "axillary". External leaf characteristics, such as shape, margin, hairs, the petiole, and
8239-469: The plant, the cells of the abscission layer remain connected; in autumn, or when under stress, the auxin flow from the leaf decreases or stops, triggering cellular elongation within the abscission layer. The elongation of these cells breaks the connection between the different cell layers, allowing the leaf to break away from the plant. It also forms a layer that seals the break, so the plant does not lose sap. Some trees, particularly oaks and beeches, exhibit
8346-434: The presence of stipules and glands, are frequently important for identifying plants to family, genus or species levels, and botanists have developed a rich terminology for describing leaf characteristics. Leaves almost always have determinate growth. They grow to a specific pattern and shape and then stop. Other plant parts like stems or roots have non-determinate growth, and will usually continue to grow as long as they have
8453-410: The previous two. Rotation fractions are often quotients F n / F n + 2 of a Fibonacci number by the number two terms later in the sequence. This is the case for the fractions 1/2, 1/3, 2/5, 3/8, and 5/13. The ratio between successive Fibonacci numbers tends to the golden ratio φ = (1 + √5)/2 . When a circle is divided into two arcs whose lengths are in the ratio 1:φ , the angle formed by
8560-465: The primary organs responsible for transpiration and guttation (beads of fluid forming at leaf margins). Leaves can also store food and water , and are modified accordingly to meet these functions, for example in the leaves of succulent plants and in bulb scales. The concentration of photosynthetic structures in leaves requires that they be richer in protein , minerals , and sugars than, say, woody stem tissues. Accordingly, leaves are prominent in
8667-429: The primary veins run parallel and equidistant to each other for most of the length of the leaf and then converge or fuse (anastomose) towards the apex. Usually, many smaller minor veins interconnect these primary veins, but may terminate with very fine vein endings in the mesophyll. Minor veins are more typical of angiosperms, which may have as many as four higher orders. In contrast, leaves with reticulate venation have
8774-416: The products of photosynthesis (photosynthate) from the cells where it takes place, while major veins are responsible for its transport outside of the leaf. At the same time water is being transported in the opposite direction. The number of vein endings is very variable, as is whether second order veins end at the margin, or link back to other veins. There are many elaborate variations on the patterns that
8881-429: The protective spines of cacti and the insect traps in carnivorous plants such as Nepenthes and Sarracenia . Leaves are the fundamental structural units from which cones are constructed in gymnosperms (each cone scale is a modified megaphyll leaf known as a sporophyll) and from which flowers are constructed in flowering plants . The internal organization of most kinds of leaves has evolved to maximize exposure of
8988-714: The rate exchange of carbon dioxide (CO 2 ), oxygen (O 2 ) and water vapor into and out of the internal intercellular space system. Stomatal opening is controlled by the turgor pressure in a pair of guard cells that surround the stomatal aperture. In any square centimeter of a plant leaf, there may be from 1,000 to 100,000 stomata. The shape and structure of leaves vary considerably from species to species of plant, depending largely on their adaptation to climate and available light, but also to other factors such as grazing animals (such as deer), available nutrients, and ecological competition from other plants. Considerable changes in leaf type occur within species, too, for example as
9095-456: The resin better known as benzoin from various tropical trees in the genus Styrax . The sweetgum has a Nahuatl name, Ocotzocuahuitl , which translates to 'tree that gives pine resin' from ocotl ('pine'), tzotl ('resin'), cuahuitl ('tree'), which refers to the use of the tree's resin. The common name "sweetgum" refers to the species' "sweetish gum", contrasting with the blackgum ( Nyssa sylvatica ) , only distantly related, with which
9202-531: The resources to do so. The type of leaf is usually characteristic of a species (monomorphic), although some species produce more than one type of leaf (dimorphic or polymorphic ). The longest leaves are those of the Raffia palm , R. regalis which may be up to 25 m (82 ft) long and 3 m (9.8 ft) wide. The terminology associated with the description of leaf morphology is presented, in illustrated form, at Wikibooks . Where leaves are basal, and lie on
9309-446: The secondary veins, known as tertiary or third order (or higher order) veins, forming a dense reticulate pattern. The areas or islands of mesophyll lying between the higher order veins, are called areoles . Some of the smallest veins (veinlets) may have their endings in the areoles, a process known as areolation. These minor veins act as the sites of exchange between the mesophyll and the plant's vascular system. Thus, minor veins collect
9416-516: The seeds of the tree. The seeds stratify within 30–90 days at 1–5 °C (33–41 °F) or soaked in water for 15–20 days. The long-stemmed fruit balls of Liquidambar resemble those of the American sycamore or buttonwood ( Platanus occidentalis ), but are spiny and remain intact after their seeds are dispersed; the softer fruits of Platanus disintegrate upon seed dispersal. The long-persisting fallen spiked fruits can be unpleasant to walk on; sweet gum
9523-455: The sequence 180°, 90°, 180°, 270°. Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade being separated along a main or secondary vein. The leaflets may have petiolules and stipels,
9630-454: The smaller arc is the golden angle , which is 1/φ × 360° ≈ 137.5° . Because of this, many divergence angles are approximately 137.5° . In plants where a pair of opposite leaves grows from each node, the leaves form a double helix. If the nodes do not rotate (a rotation fraction of zero and a divergence angle of 0°), the two helices become a pair of parallel lines, creating a distichous arrangement as in maple or olive trees. More common in
9737-585: The southern limit of distribution in Florida. This species occurs abundantly at Highlands Hammock State Park in Sebring , Highlands County, Florida , and even southwest of Lake Okeechobee . Sweetgum (Liquidambar styraciflua) is one of the most important commercial hardwoods in the Southeastern United States . Its wood is bright reddish brown (with the sapwood nearly white) and may have black grain in
9844-953: The species that bear them, the majority, as broad-leaved or megaphyllous plants, which also include acrogymnosperms and ferns . In the lycopods , with different evolutionary origins, the leaves are simple (with only a single vein) and are known as microphylls . Some leaves, such as bulb scales, are not above ground. In many aquatic species, the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines . Furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes , and flattened leaf stems called phyllodes which differ from leaves both in their structure and origin. Some structures of non-vascular plants look and function much like leaves. Examples include
9951-421: The stem is known as phyllotaxis . A large variety of phyllotactic patterns occur in nature: In the simplest mathematical models of phyllotaxis , the apex of the stem is represented as a circle. Each new node is formed at the apex, and it is rotated by a constant angle from the previous node. This angle is called the divergence angle . The number of leaves that grow from a node depends on the plant species. When
10058-547: The stomatal complex; guard cells and subsidiary cells. The epidermal cells are the most numerous, largest, and least specialized and form the majority of the epidermis. They are typically more elongated in the leaves of monocots than in those of dicots . Chloroplasts are generally absent in epidermal cells, the exception being the guard cells of the stomata . The stomatal pores perforate the epidermis and are surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts, forming
10165-530: The summer of 1994 in the Nacogdoches County area of Texas, a prominent leaf spot on sweetgum was widespread. Infected leaves had numerous necrotic lesions , each surrounded by a reddish halo. The lesions tended to merge resulting in large areas of dead tissue. Infection and fungal development of D. dryina were investigated on leaves of sweetgum using a combination of microscopic techniques. D. dryina infection on sweetgum has been associated with
10272-511: The surrounding air , promoting cooling. Functionally, in addition to carrying out photosynthesis, the leaf is the principal site of transpiration , providing the energy required to draw the transpiration stream up from the roots, and guttation . Many conifers have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and frost. These are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. Some leaf forms are adapted to modulate
10379-449: The sweetgum overlaps broadly in range. The species is also known as the "redgum", for its reddish bark. The earliest known published record of Liquidambar styraciflua is in a work by Spanish naturalist Francisco Hernández published posthumously in 1615, in which he describes the species as a large tree producing a fragrant gum resembling liquid amber, whence the genus name Liquidambar. In John Ray 's Historia Plantarum (1686) it
10486-632: The transportation system. Typically leaves are broad, flat and thin (dorsiventrally flattened), thereby maximising the surface area directly exposed to light and enabling the light to penetrate the tissues and reach the chloroplasts , thus promoting photosynthesis. They are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance, plants adapted to windy conditions may have pendent leaves, such as in many willows and eucalypts . The flat, or laminar, shape also maximizes thermal contact with
10593-498: The tree. However, the wood is heavy and hard with an interlocking grain, but is difficult to season. The leaves usually have five (but sometimes three or seven) sharply pointed palmate lobes. They are 8–13 cm (3–5 in) wide on average and have three distinct bundle scars. They are long and broad, with a 6–10 cm ( 2 + 1 ⁄ 4 –4 in) petiole. The rich dark green, smooth, shiny, star-shaped leaves generally turn brilliant yellow, orange, red, and purple colors in
10700-466: The trees; these have been popularly nicknamed "burr (or bir) balls", "gum balls", "space bugs", "sticker balls", "spike balls", or "monkey balls". The fruit is a multicapsular spherical head and hangs on the branches during the winter. The woody capsules are mostly filled with abortive seeds resembling sawdust. The seeds are about 6 mm ( 1 ⁄ 4 in) thick, winged, and wind-dispersed. Goldfinches, purple finches, squirrels, and chipmunks eat
10807-464: The uterine lining that sheds off after birth. In botany and horticulture , deciduous plants , including trees , shrubs and herbaceous perennials, are those that lose all of their leaves for part of the year. This process is called abscission . In some cases leaf loss coincides with winter—namely in temperate or polar climates . In other parts of the world, including tropical, subtropical, and arid regions, plants lose their leaves during
10914-462: The vascular structure of the organ, extending into the leaf via the petiole and providing transportation of water and nutrients between leaf and stem, and play a crucial role in the maintenance of leaf water status and photosynthetic capacity. They also play a role in the mechanical support of the leaf. Within the lamina of the leaf, while some vascular plants possess only a single vein, in most this vasculature generally divides (ramifies) according to
11021-456: The world, including moderately high elevations in the tropics. It is highly regarded in Bogota , Colombia . The species grows best in moist, acidic loam or clay soil, and tolerates poor drainage. It typically grows with other coastal plain species such as willow oak and sweetbay magnolia . Its salt tolerance is moderate. Chlorosis can develop on alkaline soil, especially where organic matter
11128-548: Was first given by Linnaeus in 1753 from the Latin liquidus ('fluid') and the Arabic ambar ('amber'), in allusion to the fragrant terebinthine juice or gum which exudes from the tree. Its specific epithet styraciflua is an old generic name meaning 'flowing with storax' (a plant resin). The name " storax " has long been confusingly applied to the aromatic gum or resin of this species, that of L. orientalis of Turkey, and to
11235-509: Was formerly used in the interior finish of railroad sleeping cars . Being readily dyed black, it is sometimes substituted for ebony for such uses as inexpensive picture frames . The wood is also used to make chopsticks for the East Asian market, as it has a naturally light color with appeal to certain segments of the Asian market. The tree's gum resin , for which the tree is named, exudes from
11342-501: Was introduced into Europe in 1681 by John Banister , the missionary collector sent out by Bishop Compton , who planted it in the palace gardens at Fulham in London , England . An ancestor of Liquidambar styraciflua is known from Tertiary -aged fossils in Alaska , Greenland , and the mid-continental plateau of North America, much further north than Liquidambar now grows. A similar plant
11449-548: Was used both medicinally and to make chewing gum . L. styraciflua seeds may be a renewable source of shikimic acid . Traditionally, sweet gum has been used in Chinese medicine to treat issues such as diarrhea , coughs, and skin sores . Liquidambar styraciflua is a popular ornamental and forestal tree, cultivated for its distinctive foliage and intense autumn colors. It is commonly grown throughout its native North American range as well as many other temperate parts of
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