The Afrotropical realm is one of the Earth's eight biogeographic realms . It includes Sub-Saharan Africa , the southern Arabian Peninsula , the island of Madagascar , and the islands of the western Indian Ocean . It was formerly known as the Ethiopian Zone or Ethiopian Region .
81-511: 184; see text Streptocarpus ("twisted fruit" from Greek στρεπτός ( streptos ) "twisted" and καρπός ( carpos ) "fruit") is an Afrotropical genus of flowering plants in the family Gesneriaceae . The genus is native to Afromontane biotopes from central, eastern and southern Africa , including Madagascar and the Comoro Islands . The flowers are five-petalled, salverform tubes, almost orchid -like in appearance, and hover or arch over
162-528: A monophyletic group , and were placed in section Saintpaulia of Streptocarpus subgenus Streptocarpella . All the species previously placed in the genus Saintpaulia are now placed in Streptocarpus section Saintpaulia . Ten species were recognized, as of March 2020 . Formerly recognized Saintpaulia species and infraspecies are listed below with their accepted name in Streptocarpus . Saintpaulias are native to eastern tropical Africa . There
243-790: A tropical climate. A broad belt of deserts , including the Atlantic and Sahara deserts of northern Africa and the Arabian Desert of the Arabian Peninsula , separates the Afrotropic from the Palearctic realm , which includes northern Africa and temperate Eurasia . South of the Sahara , two belts of tropical grassland and savanna run east and west across the continent, from the Atlantic Ocean to
324-462: A 2-10 cm petiole , finely hairy , and have a fleshy texture. The flowers are 2-3 cm in diameter, with a five-lobed velvety corolla ("petals"), and grow in clusters of 3-10 or more on slender stalks called peduncles. Wild species can have violet, purple, pale blue, or white flowers . The plants get their common name "African violet" from their superficial resemblance to true violets ( Viola , family Violaceae ). This group of plants has lived in
405-463: A broad belt across the continent, south of the rainforests of the Guineo-Congolian region , and north of the deserts of southeastern Africa, the countries are Malawi , Angola , Botswana , Mozambique , Zambia , and Zimbabwe , and the subtropical. Southern Africa contains several deserts. The Namib Desert is one of the oldest deserts in the world and extends for over 2,000 kilometers along
486-683: A labelled drawing of a vertical cross-section along the length of a Streptocarpus flower. It is important to note that the two anthers (each arising from one filament on each side of the flower), are loosely joined together. As the anthers mature, they open slightly and act like a pepper shaker, which means that not all the pollen is released at once. Streptocarpus flowers have evolved to be pollinated by birds, long-tongued flies, butterflies and probably long-tongued moths and bees. Although almost any small insect, animal, or breeze could potentially pollinate Streptocarpus . Streptocarpus flowers often have nectar guidelines that guide would-be pollinators to
567-469: A lush rainforest. Streptocarpus sect. Saintpaulia See text . Streptocarpus sect. Saintpaulia is a section within Streptocarpus subgenus Streptocarpella consisting of about ten species of herbaceous perennial flowering plants in the family Gesneriaceae , native to Tanzania and adjacent southeastern Kenya in eastern tropical Africa . The section was previously treated as
648-714: A separate genus, Saintpaulia , but molecular phylogenetic studies showed that it was nested within the genus Streptocarpus . Species and cultivars are commonly called African violets (although they are not closely related to true violets ) or saintpaulias . They are commonly sold as house plants. Several of the species and subspecies of the section are endangered , and many more are threatened, as their native cloud forest habitats are cleared for agriculture . The conservation status of Streptocarpus ionanthus has been classed as near-threatened . Saintpaulias, which grow from 6-15 cm tall, can be anywhere from 6-30 cm wide. The leaves are rounded to oval, 2.5-8.5 cm long with
729-609: A source of steady income. Land use change spoils entire habitats with the forests. The conversion of forests into timber is another cause of deforestation. Over decades, the primary forest product was commercial timber . Urbanized countries account for a great percentage of the world's wood consumption, which increased greatly between 1950 and 1980. Simultaneously, preservation measures were reinforced to protect European and American forests. Economic growth and growing environmental protection in industrialized European countries caused increased demand for tropical hardwood from West Africa. In
810-464: A special habitat that allows for a diversity of life. The top canopy is home to monkey species like the red colobus , Black-and-white Colobus, and many other Old-World monkey species. Many of these rare and unique species are endangered or critically endangered and need protection from poachers and provided ample habitat to thrive. In Tropical Africa, about 8,500 plant species have been documented, including 403 orchid species. Species unfamiliar with
891-553: A twisted fruit, African violets evolved from within the Tanzanian Streptocarpus subgenus Streptocarpella . There are a few Asian species that have recently been removed from the genus, most notably Streptocarpus orientalis , now reclassified as Damrongia orientalis . Molecular systematics has shown conclusively that they are not true Streptocarpus . There are two subgenera within Streptocarpus , namely subgenus Streptocarpus and subgenus Streptocarpella . Within
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#1732877259317972-856: A zone of forest-savanna mosaic that reaches to the coast, separates the Upper Guinean forests from the Lower Guinean forests , which extend along the Gulf of Guinea from eastern Benin through Cameroon and Gabon to the western Democratic Republic of the Congo . The largest tropical forest zone in Africa is the Congolian forests of the Congo Basin in Central Africa. A belt of tropical moist broadleaf forest also runs along
1053-454: Is a concentration of species in the Nguru mountains of Tanzania . Saintpaulias are widely cultivated as house plants . Until recently, only a few of the ten or so species that exist have been used in breeding programs for the hybrids available in the market; most of the cultivars available as house plants are derived from Streptocarpus ionanthus (syn. S. kewensis ). A wider range of species
1134-475: Is being considered for merging .› Each grower will have their own preferences for cultivation. The details given below are a tested general guide, but Streptocarpus will do quite well on either side of these optimums. The two main things to remember when growing Streptocarpus are that they do not like soil that is too wet, and they do not like it too hot. Soil: Use an ordinary commercial potting mix with 1/8 to 1/4 perlite mixed in. This makes sure
1215-434: Is common for older leaves to die off occasionally, but especially in winter. They may be snipped off. New leaves will replace them. The leaves of some perennial, but usually unifoliate Streptocarpus , are unusual because, as winter approaches, they slowly die back to an abscission line midway down the leaf. The end portion of the leaf will gradually die back to this line. In most flowering plants, an abscission line forms at
1296-430: Is generally believed that firewood provides 75% of the energy used in sub-Sahara Africa. With the high demand, the consumption of wood for fuel exceeds the renewal of forest cover . Other observed changes in these forests are forest disintegration (changing the spatial continuity and creating a mosaic of forest blocks and other land cover types), and selective logging of woody species for profitable purposes that affect
1377-734: Is home to several endemic plant families. Madagascar and the Indian Ocean Islands are home to ten endemic families of flowering plants; eight are endemic to Madagascar ( Asteropeiaceae , Didymelaceae , Didiereaceae , Kaliphoraceae , Melanophyllaceae , Physenaceae , Sarcolaenaceae , and Sphaerosepalaceae ), one to Seychelles ( Mesdusagynaceae ), and one to the Mascarene Islands ( Psiloxylaceae ). Twelve plant families are endemic or nearly endemic to South Africa (including Curtisiaceae , Heteropyxidaceae , Penaeaceae , Psiloxylaceae , and Rhynchocalycaceae ) of which five are endemic to
1458-414: Is normal. However, some varieties flower in winter. Pruning of leaves & flowers: You may slice off yellowing or browned leaves at the base - these will be the older leaves naturally dying off. If there is a healthy leaf with some blemishing, you can successfully cut off only the blemished parts and trim the leaf to a normal shape. With regards to flowers, snip off individuals as they finish, then snip
1539-612: Is now being looked at as sources of genes to introduce into modern cultivars. The African Violet Society of America is the International Cultivar Registration Authority for the section and its cultivars. Plants can be classified as one of several sizes based on their above-ground diameter. The size per category is not rigid, but a general guideline. Saintpaulias are highly sensitive to temperature changes, especially rapid leaf cooling. Spilling cold water on African violet leaves causes discoloration. This
1620-422: Is of the rosulate type. The flowers of modern rosulate hybrids are generally three to several centimeters in diameter. The other plurifoliate type is essentially somewhere in between a rosulate and a unifoliate. In this group, two or three leaves grow in addition to the first leaf. The plurifoliates are perennial. Examples are Streptocarpus prolixus , and Streptocarpus polyanthus ssp polyanthus . The second form
1701-608: Is rich in terms of biodiversity. Tropical African forest is 18 percent of the world's total and covers over 3.6 million square kilometers of land in West, East, and Central Africa. This total area can be subdivided to 2.69 million square kilometers (74%) in Central Africa, 680,000 square kilometers (19%) in West Africa, and 250,000 square kilometers (7%) in East Africa . In West Africa , a chain of rain forests up to 350 km long extends from
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#17328772593171782-460: Is the unifoliate , which only has one leaf. In the unifoliates group, one single leaf grows continuously from the base. Many unifoliates are also monocarpic , which means that they will flower once, set seed, then die. But they may take a few years to reach this stage. In other unifoliates, the original leaf may die, but one or two new leaves will sprout from it, and the plant continues to grow. This subgenus (comprising plurifoliates and unifoliates)
1863-408: Is thought to be because rapid leaf cooling causes cell vacuole collapse in the palisade mesophyll cells. African violets are commonly propagated asexually . Plants can be divided into smaller daughter plants or even grown from leaf cuttings. Growing African violets from seed is rare, and most commercially available plants are produced from cuttings and tissue culture . The African violet
1944-477: Is unique in that, in winter, they can form abscission lines part way down the leaf (see photo gallery below). The leaf then dies back to this point, whilst the proximal part of the leaf stays alive and healthy. In unifoliate species, the remaining healthy portion of that leaf will start to grow again from the base. Members of the Streptocarpus subgenus Streptocarpella are very different in form to those mentioned above. The flowers and seed pods are similar, but
2025-449: The Cape floristic province (including Grubbiaceae ). Other endemic Afrotropic families include Barbeyaceae , Dirachmaceae , Montiniaceae , Myrothamnaceae , and Oliniaceae . The East African Great Lakes ( Victoria , Malawi , and Tanganyika ) are the center of biodiversity of many freshwater fishes, especially cichlids (they harbor more than two-thirds of the estimated 2,000 species in
2106-772: The Ethiopian Highlands . Immediately south of the Sahara lies the Sahel belt, a transitional zone of semi-arid short grassland and vachellia savanna. Rainfall increases further south in the Sudanian Savanna , also known simply as the Sudan region , a belt of taller grasslands and savannas . The Sudanian Savanna is home to two great flooded grasslands : the Sudd wetland in South Sudan , and
2187-575: The Niger Inland Delta in Mali . The forest-savanna mosaic is a transitional zone between the grasslands and the belt of tropical moist broadleaf forests near the equator . South Arabia, which includes Yemen and parts of western Oman and southwestern Saudi Arabia , has few permanent forests. Some of the notable ones are Jabal Bura , Jabal Raymah , and Jabal Badaj in the Yemeni highland escarpment and
2268-441: The Streptocarpus subgenus Streptocarpus , there are two main forms, the plurifoliates and the unifoliates. Streptocarpus with more than one leaf are called "plurifoliates", and there are two main types of these. First is the rosulate form, which is perennial . Rosulates are made up of a basal rosette of leaves. Flower stems sprout from the upper surfaces of the bases of these leaves. The most common Streptocarpus houseplant
2349-428: The indigenous peoples of Africa who have occupied them for millennia. Many African countries are in economic and political change, overwhelmed by conflict, making various movements of forest exploitation to maintain forest management and production more and more complicated. Forest legislation of ATO member countries aims to promote the balanced utilization of the forest domain and of wildlife and fishery to increase
2430-823: The proteas ( Proteaceae ) that are also found in the Australasian realm . Madagascar and neighboring islands form a distinctive sub-region of the realm, with numerous endemic taxa , such as lemurs . Madagascar and the Granitic Seychelles are old pieces of the ancient supercontinent of Gondwana , and broke away from Africa millions of years ago. Other Indian Ocean islands , like the Comoros and Mascarene Islands , are volcanic islands that formed more recently. Madagascar contains various plant habitats, from rainforests to mountains and deserts, as its biodiversity and ratio of endemism are extremely high. The Afrotropical realm
2511-952: The secretary bird (Sagittariidae), guineafowl (Numididae), and mousebirds (Coliidae). Several families of passerines are limited to the Afrotropics, including rock-jumpers (Chaetopidae) and rockfowl (Picathartidae). Africa has three endemic orders of mammals, the Tubulidentata ( aardvarks ), Afrosoricida ( tenrecs and golden moles ), and Macroscelidea ( elephant shrews ). The East-African plains are well known for their diversity of large mammals. Four species of great apes ( Hominidae ) are endemic to Central Africa: both species of gorilla ( western gorilla , Gorilla gorilla , and eastern gorilla , Gorilla beringei ) and both species of chimpanzee ( common chimpanzee , Pan troglodytes , and bonobo , Pan paniscus ). Humans and their ancestors originated in Africa. The tropical environment
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2592-573: The Atlantic coasts of Angola , Namibia , and South Africa . It is characterized by towering dunes and a diversity of endemic wildlife. Further inland concerning the Namib Desert, the Kalahari Desert is a semi-arid savanna spanning Botswana , Namibia , and South Africa . The Kalahari is known for its diversity of mineral resources, particularly diamonds , as well as a variety of flora. South of
2673-721: The Indian Ocean coast, from southern Somalia to South Africa . In northeastern Africa, semi-arid Acacia-Commiphora woodlands, savannas, and bushlands are the dominant plant communities. This region is called the Somali-Masai center of endemism or Somali-Masai region. It extends from central Tanzania northwards through the Horn of Africa and covers portions of Tanzania , Kenya , Ethiopia , Somalia , Djibouti , and Eritrea . Thorny, dry-season deciduous species of Vachellia and Senegalia (formerly Acacia ) and Commiphora are
2754-725: The Namib and Kalahari deserts is the Karoo . A semi-desert natural region, the Karoo desert spans across parts of the Western and Eastern Cape in South Africa and contains vast open spaces and unique vegetation, such as certain species of Asteraceae flowering plants. Within the boundaries of the larger Karoo, the Tankwa Karoo is a more arid sub-region known for harsher conditions and starker landscapes. Further to
2835-563: The Reverend W.E. Taylor, had earlier collected and submitted specimens to the Royal Botanic Gardens, Kew , in 1884 and 1887 respectively, but the quality of specimens was insufficient to permit scientific description at that time. Revisions of the genus by B.L. Burtt expanded the genus to approximately 20 species. Following studies which showed most of the species to be very poorly differentiated, both genetically and morphologically ,
2916-557: The annual mean air temperature on land—based on molecules from the cell membrane of soil-inhabiting bacteria. Scientists from the NIOZ, Royal Netherlands Institute for Sea Research conducted a temperature record dating back to 25,000 years ago. In concordance with their German colleagues at the University of Bremen , this detailed record shows the history of land temperatures based on the molecular fossils of soil bacteria. When applying this to
2997-547: The annual pace of deforestation in the region can vary from 150 km (58 sq mi) in Gabon to 2,900 km (1,100 sq mi) in Côte d'Ivoire . The remaining tropical forests still cover major areas in Central Africa but are abridged by patches in West Africa. The African Timber Organization member countries eventually recognized the cooperation between rural people and their forest environment. Customary law gives residents
3078-504: The atmosphere, and lessen the planet's ability to store excess carbon . The rainforest vegetation of the Guinea-Congolian transition area, extending from Senegal to western Uganda is constituted of two main types: The semi-deciduous rainforest is characterized by a large number of trees whose leaves are left during the dry season. It appears in areas where the dry period (rainfall below about 100 mm) reaches three months. Then,
3159-507: The base of the leaf, and the whole leaf will fall off (e.g. the leaves of deciduous trees like oak ). Propagation is usually either by seed or leaf cuttings. Some species produce plantlets from the roots, which can be used to propagate the plant. Mature clumps of plants can also be divided up and repotted. Streptocarpus species seed that has been self-pollinated will grow true to type. Self-pollinated hybrid seed will not grow true to type. The only way to propagate hybrid plants and retain
3240-462: The biodiverse Eastern Arc Usambara Mountains in Tanga Province for millions of years. The name in the local Kisambaa language is Dughulushi. The Germans officially colonialized this area from about 1885, and shortly before this, Baron Walter von Saint Paul-Illaire (1860–1940) was made district commissioner of Tanga province , Tanganyika (now Tanzania ) in Africa. He used to enjoy walking in
3321-411: The bottom of the pot. You can then snip these plantlets off (preferably with their attached roots), and plant up as for leaf propagation above). By clump division: You can divide a multi-crown clump into pieces (each with a root system), and plant up as for leaf propagation above. For Streptocarpus subgenus Streptocarpella : By seed: Streptocarpus seed is generally very fine. To germinate,
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3402-580: The changes in forest structure for industrial use might not survive. If timber use continues and an increasing amount of farming occurs, it could lead to the mass killing of animal species. The home of nearly half of the world's animals and plant species are tropical rainforests. The rainforests provide economic resources for over-populated developing countries. Despite the stated need to save the West African forests, there are varied opinions on how best to accomplish this goal. In April 1992, countries with some of
3483-421: The characteristics of the hybrid, is by leaf propagation (or other types of vegetative cloning) For Streptocarpus subgenus Streptocarpus : By seed: Streptocarpus seed is generally very fine (see image gallery below). To germinate, the seed must be scattered thinly on top of potting mix, as they require light to germinate. The pot they are sown in must be covered in clear plastic “cling film” to keep up
3564-416: The coasts of Sierra Leone, Liberia , Ivory Coast , Ghana, continuing through Togo, Benin , Nigeria and Cameroon, and ending at the Congo Basin . Rainforests such as these are the richest, oldest, most prolific, and most complex systems on Earth, are dying, and in turn, are upsetting the delicate ecological balance. This may disturb global hydrological cycles , release vast amounts of greenhouse gases into
3645-453: The common name for subgenus Streptocarpus is Cape primrose , referring to the nativity of several species to South Africa and their superficial resemblance to the unrelated genus Primula . The common name for subgenus Streptocarpella is nodding violet . Streptocarpus sect. Saintpaulia (" African violet ") is a separate section within Streptocarpus subgenus Streptocarpella . DNA studies have shown that, despite not having
3726-437: The different molecules from the algal cell membrane can approximate the past temperature of the sea surface. The new “proxy” used in this sediment core obtained both a continental and a sea surface temperature record. In comparison, both records show that ocean surface and land temperatures behaved differently during the past 25,000 years. During the last ice age, African temperatures were 21 °C, about 4 °C lower than today, while
3807-895: The dominant trees, growing in open-canopied woodlands, open savannas, dense bushlands, and thickets . This region includes the Serengeti ecosystem, which is renowned for its wildlife. The Afromontane region extends from the Ethiopian Highlands to the Drakensberg Mountains of South Africa, including the East African Rift . This region is home to distinctive flora, including Podocarpus and Afrocarpus , as well as giant Lobelias and Senecios . The Zambezian region includes woodlands, savannas, grasslands, and thickets. Characteristic plant communities include Miombo woodlands , drier mopane and Baikiaea woodlands, and higher-elevation Bushveld . It extends from east to west in
3888-552: The eastern border of Sierra Leone to Ghana . In Ghana, the forest zone gradually dispels near the Volta river , following a 300 km stretch of Dahomey savanna gap. The rain forest of West Africa continues from east of Benin through southern Nigeria and officially ends at the border of Cameroon along the Sanaga river . Semi-deciduous rainforests in West Africa begin at the fringed coastline of Guinea Bissau (via Guinea) and run through
3969-457: The evergreen or the semi-evergreen rainforest climatically adapted to somewhat more humid conditions than the semi-deciduous type and is usually there in areas where the dry period is shorter than two months. This forest is usually richer in legumes and a variety of species and its maximum development is around the Bight of Biafra , from Eastern Nigeria to Gabon, and with some large patches leaning to
4050-419: The family). The West African coastal rivers region covers only a fraction of West Africa, but harbors 322 of West Africa's fish species, with 247 restricted to this area and 129 restricted even to smaller ranges. The central rivers fauna comprise 194 fish species, with 119 endemics and only 33 restricted to small areas. The Afrotropic has various endemic bird families, including ostriches (Struthionidae),
4131-647: The first half of the 1980s, an annual forest loss of 7,200 km (2,800 sq mi) was noted down along the Gulf of Guinea , a figure equivalent to 4-5 percent of the total remaining rainforest area. By 1985, 72% of West Africa's rainforests had been transformed into fallow lands and an additional 9% had been opened up by timber exploitation. Tropical timber was used in Europe following World War II , as trade with East European countries stopped and timber noticeably became sparse in western and southern Europe . Despite efforts to promote lesser-known timber species use,
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#17328772593174212-774: The forest subfloor and the biodiversity. The rainforests that remain in West Africa now greatly differ in condition from their state 30 years ago. In Guinea, Liberia, and the Ivory Coast, there is almost no primary forest cover left unscathed; in Ghana, the situation is much worse, and nearly all of the rainforest is being removed. Guinea-Bissau loses 200 to 350 km (77 to 135 sq mi) of forest yearly, Senegal 500 km (190 sq mi) of wooded savanna, and Nigeria 6,000,050,000 of both. Liberia loses 800 km (310 sq mi) of forests each year. Extrapolating from present rates of loss, botanist Peter Raven pictures that
4293-454: The humidity. Leaf segments, cut either horizontally across the leaf, or length-wise along the leaf (removing the midrib), can be used as cuttings in much the same way. Place the segments cut-side down in soil, as above. For unifoliates, this method is apparently less successful, but not impossible. However, it must be done before the plant flowers. Streptocarpus leaves have a high concentration of cytokinin (a type of rooting hormone), so
4374-410: The humidity. Keep the sown seed where it will get bright, indirect light, and remain about 18-20 degrees Celsius. Keep them out of direct sunlight. By leaf: A Streptocarpus leaf can be severed at the base, taking some petiole (but above where flowers arise), and potted, base-down, in a few centimetres of potting mix. Place a clear plastic bag over the pot and secure with a rubber band to keep up
4455-512: The input of the forest sector to the economic, social, cultural, and scientific development of the country. The rate of deforestation in Africa is less known than the rate of other tropical regions. A lack of dependable data and survey information in some countries has made change in areas of unbroken forest difficult to ascertian. The cultivation of various cash crops has led to forest depletion. West African countries depend on products like gum, copal , rubber , cola nuts , and palm oil as
4536-465: The largest surviving tropical rainforests banned a rainforest protection plan proposed by the British government . It aimed at finding endangered species of tropical trees to control their trade. Experts estimate that the rainforest of West Africa, at the present rate of deforestation , may disappear by the year 2020. Africa's rainforest, like many others emergent in the world, has a special significance to
4617-486: The leaves and stems are caulescent (have stems). Streptocarpellas are generally clump-forming or trailing plants. Their flowers are only about 2.5-3.5 cm in diameter, and their colour range seems to be limited to mid-purples, pale pinks, and white. Streptocarpella leaves can be decussate in arrangement (each pair of leaves at a node is at 90 degrees to the ones preceding or following it), or ternate (whorls of 3 leaves at each node). Some specimens may exhibit both on
4698-568: The majority of the world's moderate and smaller rainforests (such as in Africa) could be destroyed in forty years. Tropical Africa comprises 18% of the world's total land area covering 20 million km (7.7 million sq mi) of land in West and Central Africa. The region has been facing deforestation in various degrees of intensity throughout the recent decades. The actual rate of deforestation varies from one country to another and accurate data does not exist yet. Recent estimates show that
4779-403: The market continued to focus on part of the usable timber obtainable. West Africa was prone to selective harvesting practices; while conservationists blamed the timber industry and the farmers for felling trees, others believe rainforest destruction is connected to the problem of fuel wood. The contribution of fuel wood consumption to tree stock decline in Africa is believed to be significant. It
4860-452: The nectar (and anthers and stigmas). Self-pollination is also common. 184 species of Streptocarpus are currently recognized. Streptocarpus rexii is the first species described. A complete list of the species and their synonyms can be found at the Smithsonian's World Checklist of Gesneriaceae. A list of selected species from representative locales follows: ‹The template Manual
4941-557: The number of species was reduced to six in a 2006 treatment, with the majority of former species reduced to subspecies under S. ionantha . In 2009, 9 species , 8 subspecies , and 2 varieties were recognized. A molecular phylogenetic study in 2015 confirmed previous studies showing that species placed in Saintpaulia were deeply embedded within the genus Streptocarpus , supporting the transfer of all Saintpaulia species to Streptocarpus in 2012. Former Saintpaulia species did form
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#17328772593175022-566: The outflow core of the Congo River , the core contained eroded land material and microfossils from marine algae. That concluded that the land environment of tropical Africa cooled more than the bordering Atlantic Ocean during the last ice age. Since the Congo River drains a large part of tropical central Africa, the land-derived material gives an integrated signal for a very large area. These findings further enlighten natural disparities in climate and
5103-431: The plant, while the pointed, elongate fruit is of a helical form similar to that of the "tusk" of a narwhal . In the wild, species can be found growing on shaded rocky hillsides or cliffs, on the ground, in rock crevices, and almost anywhere the seed can germinate and grow. For the home, there are now many hybrids of various colours and forms available. Although generally referred to simply as "Streptocarpus" or "Streps",
5184-576: The possible costs of a warming earth on precipitation in central Africa. Scientists discovered a way to measure sea temperature—based on organic molecules from algae growing off the surface layer of the Ocean. These organisms acclimatize the molecular composition of their cell membranes to ambient temperature to sustain regular physiological properties. If such molecules sink to the sea floor and are buried in sediments where oxygen does not go through, they can be preserved for thousands of years. The ratios between
5265-419: The process. The species that compose African rainforests are of different evolutionary ages because of the contraction and expansion of the rainforest in response to global climatic fluctuations. The pygmy hippopotamus , the giant forest hog , the water chevrotain , insectivores , rodents, bats, tree frogs, and bird species inhabit the forest. These species, along with a diversity of fruits and insects, make
5346-487: The rainforest and they reminded him of the violets back home. He called them Usambaraveilchen (Usambara violets). In 1892 he sent seeds back to his father, who gave them to an amateur botanist, Hermann Wendland , in Germany . Wendland scientifically described the genus Saintpaulia , and original species S. ionantha in 1893, naming the genus for Saint Paul-Illaire and his father. Two British plant enthusiasts, Sir John Kirk and
5427-414: The right to use trees for firewood, fell trees for construction, and collect of forest products and rights for hunting or fishing and grazing or clearing of forests for maintenance agriculture. Other areas are called "protected forests", which means that uncontrolled clearings and unauthorized logging are forbidden. After World War II, commercial exploitation increased until no West African forestry department
5508-399: The same plant. Streptocarpella are grown as houseplants, hanging plants, and sometimes as bedding plants. These two Streptocarpus subgenera do not interbreed. For information on Streptocarpus subgenus Streptocarpella section Saintpaulia , see Streptocarpus sect. Saintpaulia . Streptocarpus flowers are five-lobed, salverform, zygomorphic tubes. The diagram at the right shows
5589-482: The seasonal forests in eastern Yemen and the Dhofar region of Oman. Other woodlands that scatter the land are small, predominantly Juniperus or Vachellia forests. The forest zone , a belt of lowland tropical moist broadleaf forests , runs across most of equatorial Africa's Intertropical Convergence Zone . The Upper Guinean forests of West Africa extend along the coast from Guinea to Togo . The Dahomey Gap ,
5670-473: The seed must be scattered thinly on top of potting mix, as they require light to germinate. The pot they are sown in must be covered in clear plastic “cling film” to keep up the humidity. Keep the sown seed where it will get bright, indirect light, and remain about 18-20 degrees Celsius. Keep them out of direct sunlight. Afrotropics Most of the Afrotropical realm, except for Africa's southern tip, has
5751-540: The soil is almost dry. Some growers prefer to water only when the leaves have just started to wilt (or just before). They recover very well from dehydration, and this is one of the traits of the species. Make sure the pot has holes in the bottom to drain water, and never leave the pots sitting in a saucer of water. Feeding: Feed occasionally with a "fruit and flower" or general fertilizer. Seasons: Generally, Streptocarpus will flower from spring to autumn. In winter, they will stop flowering and may lose some leaves, which
5832-473: The soil will retain some moisture but not get boggy. Always have adequate drainage holes at the bottom of the pot you are planting in. Temperature: 18–25 °C (64–77 °F). They can be taken down to 10 °C (50 °F) or less in winter for a rest. Light: Medium to bright indirect light is best. However, a bit of morning/late afternoon sun is more than okay. Even in dimmer light, they will flower - but less floriferously . Water: Water only once
5913-411: The tropical Atlantic Ocean was only about 2.5 °C cooler. Lead author Johan Weijers and his colleagues concluded that the land-sea temperature difference has by far the largest influence on continental rainfall. The relation of air pressure to temperature strongly determines this factor. During the last ice age , the land climate in tropical Africa was drier than it is now, whereas it favors the growth of
5994-400: The use of artificial rooting hormones is unnecessary. By root plantlet: Un-pot a plant that you know is susceptible to producing root plantlets (e.g. Streptocarpus johannis , and its sports ‘Falling Stars’ and 'Gloria'. You will see, once the roots are exposed, whether any plantlets have formed between the soil and pot. Sometimes, these plantlets will be evident growing out of the holes at
6075-493: The west from Ghana to Liberia and to the east of Zaïre-Congo basin. Among rainforest areas in other continents, most of the African rainforest is comparatively dry and receives between 1600 and 2000 mm of rainfall per year. Areas receiving more rain than this mainly are in coastal areas. The circulation of rainfall throughout the year remains less than in other rainforest regions in the world. The average monthly rainfall in nearly
6156-493: The west, the Richtersveld , a mountainous desert in the northwestern corner of South Africa, presents a rugged landscape. It is celebrated as a UNESCO World Heritage Site for its unique biodiversity and cultural significance to the local Nama people . The Cape floristic region at Africa's southern tip is a Mediterranean climate region that is home to a significant number of endemic taxa , as well as to plant families like
6237-667: The whole region remains under 100 mm throughout the year. The variety of the African rainforest flora is also less than the other rainforests. This lack of flora has been credited to several reasons such as the gradual infertility since the Miocene , severe dry periods during Quaternary , or the refuge theory of the cool and dry climate of tropical Africa during the last severe ice age of about 18,000 years ago. The Tropical African rainforest has rich fauna, commonly smaller mammal species rarely seen by humans. New species are being discovered. For instance, in late 1988 an unknown shrub species
6318-467: The whole stem off at the base once the last flower on that stem is spent. Cut flowers: Streptocarpus flowers also make excellent cut flowers, especially the long-stemmed varieties. They last well. Pests and diseases: Streptocarpus are generally pest and disease-free. However, the most common afflictions are aphids and mealybugs . These are easily treatable with commercial insecticides or cultural pest removal methods. Leaves and abscission: It
6399-535: Was able to make the law. By comparison with rainforests in other places of the world in 1973, Africa showed the greatest infringement though in total volume means, African timber production accounted for just one-third compared to that of Asia . The difference was due to the variety of trees in Africa forests and the demand for specific wood types in Europe. Forestry regulations in East Africa were first applied by colonial governments. The Tropical Forestry Action Plan
6480-801: Was conceived in 1987 by the World Resources Institute in cooperation with the Food and Agriculture Organization , the United Nations Development Program , and the World Bank with hopes of halting tropical forest destruction. In its bid to stress forest conservation and development, the World Bank provided $ 111,103 million to developing countries, especially in Africa, to help in developing long-range forest conservation and management programs meant for ending deforestation. In early 2007, scientists created an entirely new proxy to determine
6561-553: Was discovered on the shores of the Median River in Western Cameroon. Since then many species have become extinct. However, undisturbed rainforests are some of the richest habitats for animal species. Today, undisturbed rainforests are remnant but rare. Timber extraction not only changes the edifice of the forest, but it also affects the tree species spectrum by removing economically important species and terminating other species in
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