''Streptocarpus'' sect. ''Saintpaulia'' is a section within '' Streptocarpus'' subgenus ''Streptocarpella'' consisting of about ten species of herbaceous

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s in the family

Gesneriaceae Gesneriaceae, the gesneriad family, is a family of flowering plants consisting of about 152 genera and ca. 3,540 species in the tropics and subtropics of the Old World (almost all Didymocarpoideae) and the New World (most Gesnerioideae), wi ...

, native to

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...

and adjacent southeastern

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi ...

in eastern tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. The section was previously treated as a separate genus, ''Saintpaulia'', but molecular phylogenetic studies showed that it was nested within the genus ''Streptocarpus''. Species and

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s are commonly called African violets (although they are not closely related to true

violets Violet identifies various plant taxa, particularly species in the genus ''Viola'', within which the common violet is the best known member in Eurasia and the common blue violet and common purple violet are the best known members in North America ...

) or saintpaulias. They are commonly sold as house plants. Several of the species and subspecies of the section are

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

, and many more are threatened, as their native cloud forest habitats are cleared for

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people t ...

. The conservation status of '' Streptocarpus ionanthus'' has been classed as

near-threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify f ...

Description

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 a 2-10 cm petiole, finely

hairy Hairy may refer to: * people or animals covered in hairs or fur * plants covered in trichomes * insects covered in setae * people nicknamed "the Hairy" * Hairy (gene) See also * Hairies, a fictional people * Haerye ''Hunminjeongeum Haerye'' ...

, and have a fleshy texture. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s 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 A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

. The plants get their common name "African violet" from their superficial resemblance to true

violet Violet may refer to: Common meanings * Violet (color), a spectral color with wavelengths shorter than blue * One of a list of plants known as violet, particularly: ** ''Viola'' (plant), a genus of flowering plants Places United States * Viol ...

s (''Viola'', family

Violaceae Violaceae is a family of flowering plants established in 1802, consisting of about 1000 species in about 25 genera. It takes its name from the genus ''Viola'', the violets and pansies. Older classifications such as the Cronquist system placed t ...

Taxonomy

This group of plants has lived in 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 Tanga Region (''Mkoa wa Tanga'' in Swahili) is one of Tanzania's 31 administrative regions. The region covers an area of . The region is comparable in size to the combined land area of the nation state of Burundi. The regional capital is the mu ...

Tanganyika Tanganyika may refer to: Places * Tanganyika Territory (1916–1961), a former British territory which preceded the sovereign state * Tanganyika (1961–1964), a sovereign state, comprising the mainland part of present-day Tanzania * Tanzania Main ...

(now

) in Africa. He used to enjoy walking in 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 Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. Wendland named the genus for Saint Paul-Illaire and his father. Two British plant enthusiasts, Sir John Kirk and the Reverend W.E. Taylor, had earlier collected and submitted specimens to the

Royal Botanic Gardens, Kew Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,10 ...

, in 1884 and 1887 respectively, but the quality of specimens was insufficient to permit scientific description at that time. The genus ''Saintpaulia'', and original species ''S. ionantha'', were scientifically described by H. Wendland in 1893. 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 Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ...

and morphologically, 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 In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, 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 a

monophyletic group A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, and were placed in section ''Saintpaulia'' of ''Streptocarpus'' subgenus ''Streptocarpella''.

Species

All the species previously placed in the genus ''Saintpaulia'' are now placed in ''Streptocarpus'' section ''Saintpaulia''. Ten species were recognized, . * '' Streptocarpus afroviola'' Christenh. * '' Streptocarpus albus'' (E.A.Bruce) I.Darbysh. * '' Streptocarpus brevipilosus'' (B.L.Burtt) Mich.Möller & Haston * '' Streptocarpus goetzeanus'' (Engl.) Christenh. * '' Streptocarpus inconspicuus'' (B.L.Burtt) Christenh. * '' Streptocarpus ionanthus'' (H.Wendl.) Christenh. * '' Streptocarpus nitidus'' (B.L.Burtt) Mich.Möller & Haston * '' Streptocarpus shumensis'' (B.L.Burtt) Christenh. * ''

Streptocarpus teitensis ''Streptocarpus teitensis'', synonym ''Saintpaulia teitensis'', is a species of ''Streptocarpus'' in the section '' Saintpaulia''. It is endemic to 1 square kilometer on Mbololo Hill in the Taita Hills of southern Kenya ) , national_anthem ...

'' (B.L.Burtt) Christenh. * '' Streptocarpus ulugurensis'' (Haston) Haston Formerly recognized ''Saintpaulia'' species and infraspecies are listed below with their accepted name in ''Streptocarpus''. *''Saintpaulia alba'' E.A.Bruce = '' Streptocarpus albus'' (E.A.Bruce) I.Darbysh. *''Saintpaulia amaniensis'' E.P.Roberts = '' Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. *''Saintpaulia brevipilosa'' B.L.Burtt = '' Streptocarpus brevipilosus'' (B.L.Burtt) Mich.Möller & Haston *''Saintpaulia confusa'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. *''Saintpaulia difficilis'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. *''Saintpaulia diplotricha'' B.L.Burtt = '' Streptocarpus ionanthus'' var. ''diplotrichus'' (B.L.Burtt) Christenh. *''Saintpaulia goetzeana'' Engl. = '' Streptocarpus goetzeanus'' (Engl.) Christenh. *''Saintpaulia grandifolia'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''grandifolius'' (B.L.Burtt) Christenh. *''Saintpaulia grotei'' Engl. = '' Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. *''Saintpaulia inconspicua'' B.L.Burtt = '' Streptocarpus inconspicuus'' (B.L.Burtt) Christenh. *''Saintpaulia intermedia'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''pendulus'' (B.L.Burtt) Christenh. *''Saintpaulia ionantha'' H.Wendl. = '' Streptocarpus ionanthus'' (H.Wendl.) Christenh. **''Saintpaulia ionantha'' subsp. ''grandifolia'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''grandifolius'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' subsp. ''grotei'' (Engl.) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. **''Saintpaulia ionantha'' subsp. ''mafiensis'' I.Darbysh. & Pócs = ''Streptocarpus ionanthus'' subsp. ''mafiensis'' (I.Darbysh. & Pócs) Christenh. **''Saintpaulia ionantha'' subsp. ''nitida'' (B.L.Burtt) I.Darbysh. = '' Streptocarpus nitidus'' (B.L.Burtt) Mich.Möller & Haston **''Saintpaulia ionantha'' subsp. ''occidentalis'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''occidentalis'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' subsp. ''orbicularis'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''orbicularis'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' subsp. ''pendula'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''pendulus'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' subsp. ''rupicola'' (B.L.Burtt) I.Darbysh.. = ''Streptocarpus ionanthus'' subsp. ''rupicola'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' subsp. ''velutina'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' subsp. ''velutinus'' (B.L.Burtt) Christenh. **''Saintpaulia ionantha'' var. ''diplotricha'' (B.L.Burtt) I.Darbysh. = ''Streptocarpus ionanthus'' var. ''diplotrichus'' (B.L.Burtt) Christenh. *''Saintpaulia kewensis'' C.B.Clarke = '' Streptocarpus ionanthus'' (H.Wendl.) Christenh. *''Saintpaulia magungensis'' E.P.Roberts = '' Streptocarpus ionanthus'' subsp. ''grotei'' (Engl.) Christenh. **''Saintpaulia magungensis'' var. ''occidentalis'' B.L.Burtt = ''Streptocarpus ionanthus'' subsp. ''occidentalis'' (B.L.Burtt) Christenh. *''Saintpaulia nitida'' B.L.Burtt = '' Streptocarpus nitidus'' (B.L.Burtt) Mich.Möller & Haston *''Saintpaulia orbicularis'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''orbicularis'' (B.L.Burtt) Christenh. *''Saintpaulia pendula'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''pendulus'' (B.L.Burtt) Christenh. *''Saintpaulia pusilla'' Engl. = '' Streptocarpus afroviola'' Christenh. *''Saintpaulia rupicola'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''rupicola'' (B.L.Burtt) Christenh. *''Saintpaulia shumensis'' B.L.Burtt = '' Streptocarpus shumensis'' (B.L.Burtt) Christenh. *''Saintpaulia teitensis'' B.L.Burtt = ''

'' (B.L.Burtt) Christenh. *''Saintpaulia tongwensis'' B.L.Burtt = '' Streptocarpus ionanthus'' (H.Wendl.) Christenh. *''Saintpaulia ulugurensis'' Haston = '' Streptocarpus ulugurensis'' (Haston) Haston *''Saintpaulia velutina'' B.L.Burtt = '' Streptocarpus ionanthus'' subsp. ''velutinus'' (B.L.Burtt) Christenh. *''Saintpaulia watkinsii'' Haston = '' Streptocarpus afroviola'' var. ''watkinsii'' (Haston) Christenh.

Distribution

Saintpaulias are native to eastern tropical

. There is a concentration of species in the

Nguru mountains The Nguru Mountains are a mountain range in Morogoro Region, Tanzania, Africa. The Nguru Mountains are part of the Eastern Arc Mountains. The mountains are predominantly covered with rainforest, home to 83 species of birds (Romdal 2001) and Africa ...

Cultivation

Saintpaulias are widely cultivated as

house plant A houseplant, sometimes known as a pot plant, potted plant, or an indoor plant, is an ornamental plant that is grown indoors. As such, they are found in places like residences and offices, mainly for decorative purposes. Common houseplants are us ...

s. Until recently, only a few of these species have been used in breeding programs for the hybrids available in the market; most available as house plants are

s derived from '' Streptocarpus ionanthus'' (syn. ''S. kewensis''). A wider range of species 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 An International Cultivation Registration Authority (ICRA) is an organization responsible for ensuring that the names of plant cultivars and cultivar groups are defined and not duplicated. The ICRA system was established more 50 years ago, and op ...

for the section and its cultivars.

Sizes

Plants can be classified as one of several sizes based on its above-ground diameter. Although the size per category is not set in stone, these are a general guideline. * Micro: less than 3 inches * Super-mini: 3 to 4 inches African violet (Saintpaulia)

* Mini: between 4 and 6 inches * Semi-mini: between 6 and 8–10 inches * Standard: between 8–10 and 12–16 inches * Large/Giant: over 12–16 inches

Temperature

Saintpaulias are highly sensitive to temperature changes, especially rapid leaf cooling. Spilling cold water on African violet leaves causes discoloration. This is thought to be because rapid leaf cooling causes cell vacuole collapse in the

palisade mesophyll Palisade cells are plant cells located on the leaves, right below the epidermis and cuticle that is the outermost layer of the leaf. In simpler terms, they are known as leaf cells. Palisade means "stake" in latin, they are vertically elongated an ...

cells.

Propagation

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 A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

is rare and most commercially available plants are produced from cuttings and

tissue culture Tissue culture is the growth of tissues or cells in an artificial medium separate from the parent organism. This technique is also called micropropagation. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, su ...

Flowering

The African violet is a day-neutral plant regarding flower development.

In culture

African violets have become a traditional gift in the developed world. They are often offered for sale at holidays. They are a popular house plant in many countries, as they can flower during most of the year and are fairly durable to neglect.

References

External links

* *
African Violet Society of America websiteAfrican Violet Society of Canada websiteBaby Violets - African Violet Houseplants
{{Authority control Afromontane flora Endemic flora of Tanzania Flora of East Tropical Africa Garden plants of Africa House plants Plant sections