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24-429: See text. Skimmia is a genus of four species of evergreen dioecious shrubs and small trees in the rue family Rutaceae , all native to warm temperate regions of Asia. The leaves are clustered at the ends of the shoots, simple, lanceolate , 6–21 cm long and 2–5 cm broad, with a smooth margin. The flowers are in dense panicle clusters, each flower small, 6–15 mm diameter, with 4-7 petals. The fruit

48-497: A cold or dry/wet season. Evergreen trees also lose leaves, but each tree loses its leaves gradually and not all at once. Most tropical rainforest plants are considered to be evergreens, replacing their leaves gradually throughout the year as the leaves age and fall, whereas species growing in seasonally arid climates may be either evergreen or deciduous. Most warm temperate climate plants are also evergreen. In cool temperate climates, fewer plants are evergreen. In such climates, there

72-731: A higher soil acidity and lower soil nitrogen content. This is the case with Mediterranean evergreen seedlings, which have unique C and N storages that allow stored resources to determine fast growth within the species, limiting competition and bolstering survival. These conditions favor the growth of more evergreens and make it more difficult for deciduous plants to persist. In addition, the shelter provided by existing evergreen plants can make it easier for younger evergreen plants to survive cold and/or drought. Evergreen plants can have decorative as well as functional uses. In months where most other plants are dormant, evergreens with their sturdy structure, and vibrant foliage are popular choices to beautify

96-447: A landscape. Additionally, evergreens can serve as a windbreak , stopping heat loss from buildings during cold months when placed on the northwest side of a structure. Pine See List of Pinus species for complete taxonomy to species level. See list of pines by region for list of species by geographic distribution . A pine is any conifer tree or shrub in the genus Pinus ( / ˈ p aɪ n ə s / ) of

120-420: A larger volume of parenchyma and air spaces per unit leaf area. They have larger leaf biomass per unit leaf area, and hence a lower specific leaf area . Construction costs do not differ between the groups. Evergreens have generally a larger fraction of total plant biomass present as leaves (LMF), but they often have a lower rate of photosynthesis. Deciduous trees shed their leaves usually as an adaptation to

144-564: A means to evaluate soil fertility and vigour of the trees. The bark of most pines is thick and scaly, but some species have thin, flaky bark. The branches are produced in "pseudo whorls", actually a very tight spiral but appearing like a ring of branches arising from the same point. Many pines are uninodal, producing just one such whorl of branches each year, from buds at the tip of the year's new shoot , but others are multinodal, producing two or more whorls of branches per year. Pines have four types of leaf : Pines are monoecious , having

168-438: Is a predominance of conifers because few evergreen broadleaf plants can tolerate severe cold below about −26 °C (−15 °F). In addition, evergreen foliage experiences significant leaf damage in these cold, dry climates. Root systems are the most vulnerable aspect of many plants. Even though roots are insulated by soil, which tends to be warmer than average air temperatures, soil temperatures that drop too low can kill

192-449: Is now restricted to fir ( Abies ) and Douglas-fir ( Pseudotsuga ). Pines are gymnosperms . The genus is divided into two subgenera based on the number of fibrovascular bundles in the needle. The subgenera can be distinguished by cone, seed, and leaf characters: Phylogenetic evidence indicates that both subgenera have a very ancient divergence from one another. Each subgenus is further divided into sections and subsections. Many of

216-785: Is one of the world's oldest living organisms at around 4,800 years old. This tree can be found in the White Mountains of California. An older tree, now cut down, was dated at 4,900 years old. It was discovered in a grove beneath Wheeler Peak and it is now known as " Prometheus " after the Greek immortal . The spiral growth of branches, needles, and cones scales are arranged in Fibonacci number ratios. The new spring shoots are sometimes called "candles"; they are covered in brown or whitish bud scales and point upward at first, then later turn green and spread outward. These "candles" offer foresters

240-1058: Is red to black, 6–12 mm diameter, a fleshy drupe containing a single seed. All parts of the plant have a pungent aroma when crushed. The botanical name Skimmia is a Latinization of shikimi (シキミ, 樒), which is the Japanese name for Illicium religiosum as well as an element in miyama shikimi (ミヤマシキミ, 深山樒), the Japanese name for Skimmia japonica . Skimmias are fed on by aphids, Horse Chestnut Scale, Garden Leafhopper, and Southern Red Mite. Skimmias are grown as garden plants for their foliage, flowers, and showy red fruits. They are grown in shade, with moist, well-drained, humus-rich soils. They are tolerant of both drought and air pollution. A large number of cultivars have been selected for garden use: Evergreen There are many different kinds of evergreen plants, including trees , shrubs , and vines. Evergreens include: The Latin binomial term sempervirens , meaning "always green", refers to

264-629: Is the largest genus of the Pinaceae , the pine family, which first appeared in the Jurassic period. Based on recent Transcriptome analysis, Pinus is most closely related to the genus Cathaya , which in turn is closely related to spruces . These genera, with firs and larches , form the pinoid clade of the Pinaceae. Pines first appeared during the Early Cretaceous, with the oldest verified fossil of

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288-671: The Northern Hemisphere ; they occupy large areas of boreal forest , but are found in many habitats, including the Mediterranean Basin . The timber from pine trees is called "pine"; it is one of the most extensively used types of timber. There are currently 818 named cultivars (or trinomials ) recognized by the ACS. It is a well-known type of Christmas tree . Pine trees are evergreen , coniferous resinous trees (or, rarely, shrubs ) growing 3–80 metres (10–260 feet) tall, with

312-542: The family Pinaceae . Pinus is the sole genus in the subfamily Pinoideae . World Flora Online accepts 187 species names of pines as current, with additional synonyms, making it the largest family among the conifers. The American Conifer Society (ACS) and the Royal Horticultural Society accept 121 species. The highest species diversity of pines is found in Mexico. Pines are widely distributed in

336-644: The Indo-European base *pīt- ‘resin’ (source of English pituitary ). Before the 19th century, pines were often referred to as firs (from Old Norse fura , by way of Middle English firre ). In some European languages, Germanic cognates of the Old Norse name are still in use for pines — in Danish fyr , in Norwegian fura/fure/furu , Swedish fura/furu , Dutch vuren , and German Föhre — but in modern English, fir

360-476: The area in which they reside. The excellent water economy within the evergreen species is due to high abundance when compared to deciduous species. Whereas deciduous trees lose nutrients whenever they lose their leaves. In warmer areas, species such as some pines and cypresses grow on poor soils and disturbed ground. In Rhododendron , a genus with many broadleaf evergreens, several species grow in mature forests but are usually found on highly acidic soil where

384-546: The evergreen nature of the plant, for instance: The longevity of individual leaves in evergreen plants varies from a few months to several decades (over 30 years in the Great Basin bristlecone pine ). Japanese umbrella pine is unique in that it has its own family of which it is the only species. Evergreen and deciduous species vary in a range of morphological and physiological characters. Generally, broad-leaved evergreen species have thicker leaves than deciduous species, with

408-550: The genus being Pinus yorkshirensis from the Hauterivian - Barremian boundary (~130-125 million years ago) from the Speeton Clay , England. The evolutionary history of the genus Pinus has been complicated by hybridization . Pines are prone to inter-specific breeding. Wind pollination, long life spans, overlapping generations, large population size, and weak reproductive isolation make breeding across species more likely. As

432-517: The majority of species reaching 15–45 m (50–150 ft) tall. The smallest are Siberian dwarf pine and Potosi pinyon , and the tallest is an 83.45 m (273.8 ft) tall sugar pine located in Yosemite National Park . Pines are long lived and typically reach ages of 100–1,000 years, some even more. The longest-lived is the Great Basin bristlecone pine ( P. longaeva ). One individual of this species, dubbed " Methuselah ",

456-507: The male and female cones on the same tree. The male cones are small, typically 1–5 cm long, and only present for a short period (usually in spring, though autumn in a few pines), falling as soon as they have shed their pollen . The female cones take 1.5–3 years (depending on species) to mature after pollination , with actual fertilization delayed one year. At maturity the female cones are 3–60 cm long. Each cone has numerous spirally arranged scales, with two seeds on each fertile scale;

480-423: The nutrients are less available to plants. In taiga or boreal forests , it is too cold for the organic matter in the soil to decay rapidly, so the nutrients in the soil are less easily available to plants, thus favoring evergreens. In temperate climates, evergreens can reinforce their own survival; evergreen leaf and needle litter has a higher carbon-nitrogen ratio than deciduous leaf litter , contributing to

504-448: The plant. The exact temperature which evergreen roots can handle depends on the species, for example, Picea Glauca (White Spruce) roots are killed at −10 °F (−23 °C). In areas where there is a reason for being deciduous, e.g. a cold season or dry season, evergreen plants are usually an adaptation of low nutrient levels. Additionally, they usually have hard leaves and have an excellent water economy due to scarce resources in

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528-453: The scales at the base and tip of the cone are small and sterile, without seeds. The seeds are mostly small and winged, and are anemophilous (wind-dispersed), but some are larger and have only a vestigial wing, and are bird -dispersed. Female cones are woody and sometimes armed to protect developing seeds from foragers. At maturity, the cones usually open to release the seeds. In some of the bird-dispersed species, for example whitebark pine ,

552-469: The seeds are only released by the bird breaking the cones open. In others, the seeds are stored in closed cones for many years until an environmental cue triggers the cones to open, releasing the seeds. This is called serotiny . The most common form of serotiny is pyriscence, in which a resin binds the cones shut until melted by a forest fire, for example in P. rigida . The modern English name "pine" derives from Latin pinus , which some have traced to

576-422: The smaller groups of Pinus are composed of closely related species with recent divergence and history of hybridization. This results in low morphological and genetic differences. This, coupled with low sampling and underdeveloped genetic techniques, has made taxonomy difficult to determine. Recent research using large genetic datasets has clarified these relationships into the groupings we recognize today. Pinus

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