Daubenya
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The Daubenya are a genus of plants within the asparagus family (Asparagaceae). The eight or so species occur only in South Africa , seven of them only in the two provinces of the North Cape and Western Cape , and are called Pincushion Lily there.
Description and synecology
Appearance and leaves
Daubenya species grow as perennial herbaceous plants . These geophytes form subterranean, almost spherical onions as persistence organs, whose outer casing ("tunic") is thin, leathery and brownish. The thick roots are branched.
Foliage leaves are only present during the rainy season . There are only two basal, prostrate leaves at the same time as the flowers. The simple, bald, shiny, leathery leaf blades are relatively broad and elongated to broadly elliptical. There is parallel veining and the leaf veins are sunk.
Inflorescences, flowers and pollination
Terminally on relatively short, upright inflorescence shafts and thus close to the basal leaves are compact, umbrella- shaped or rarely, due to the elongation of the inflorescence axis, racemose inflorescences that contain many flowers. There are at the bottom of large and small top, green or membranous bracts present. Cover sheets are missing. The almost upright flower stalks are short to, especially the lower ones, more or less long.
Of hermaphroditic, threefold and often fragrant flowers , the lower ones are sometimes more or less clearly zygomorphic, but most of them are radial symmetry . The six uniformly shaped or more or less clearly unequal bloom cladding sheets are fused together in a medium to very long tubular shape. The free part of the bracts is almost upright, oblong-lanceolate. In the most extreme cases of zygomorphic flowers, the upper bracts are greatly enlarged and obverse-lanceolate. The colors of the bracts are white to pink or from yellow to orange to bright red. There are two circles with three stamens each. The more or less upright stamens inserted into the throat of the petals are strong and free or have grown together to form a more or less long staminal tube. The throat of the pedicled staminal tube is rarely closed by a thickened disc and the stylus protrudes through it. The three carpels are an egg-shaped or inverted-triangular, Upper permanent ovary grown. There are some ovules in each ovary chamber . The thin, stem -round style is much longer than the ovary and ends in a tiny scar.
The pollination is very different depending on the type with very different morphological adaptations of the flowers. Honey bees and butterflies are attracted to pollinate with well-smelling flowers. In two species, the flowers are not fragrant. Daubenya zeyeri attracts nectar birds (Nectariniidae) with plenty of nectar for pollination. Daubenya aurea is visited by beetles (from the subfamily Hopliinae, Scarabaeidae ); in their " flowers " the outer bracts of the lower zygomorphic flowers are enlarged ( cantharophilia ).
Fruits, seeds and diaspore spread
The egg-shaped or inverted-triangular and then three-winged, parchment-like capsule fruits contain a few seeds in each fruit compartment. Usually the capsule fruits open when ripe, but rarely when the stylus remains as a beak they open late. The almost spherical seeds have a black, smooth or finely wrinkled, tight-fitting seed coat (testa).
Since the fruits of most species are close to the ground, they do not spread widely. It is different with Daubenya capensis with her the inflorescence stem and the peduncles are elongated until the fruit is ripe, the balloon-like fruit assembly with the winged capsule fruits and sail-like bracts expose above the ground and the seeds are spread wide by the wind.
Chromosome numbers
The basic chromosome numbers are x = 17 or 16.
Spread and endangerment
The genus Daubenya occurs almost only in the two South African provinces of the North Cape and Western Cape . Only Daubenya comata is also found in the Free State and Northwest . Six species are floral elements of the Capensis . Except for Daubenya comata , the Daubenya species have relatively small distribution areas. Daubenya species thrive almost only in winter rain areas .
All Daubenya species are on the red list of endangered species in South Africa. Daubenya aurea is considered to be "endangered" . "Vulnerable" = "at risk" are Daubenya stylosa Daubenya zeyheri . Daubenya capensis is rated as “Near Threatened”. Daubenya comata and Daubenya marginata have the status “Least Concern” = “not endangered” . Daubenya alba and Daubenya namaquensis are rare but not endangered.
Systematics
The genus Daubenya was listed in 1835 by John Lindley in Edwards's Botanical Register , 21, pl. Established in 1813. The genus name Daubenya honors English botanist Charles Daubeny . Type species is aubenya aurea Lindl. Synonyms for Daubenya Lindl. are: Amphisiphon W.F.Barker , Androsiphon Schltr. , Neobakeria Schltr.
The genus Daubenya was established with only one species and for a long time it remained monotypical . In Alison M. van der Merwe & John C. Manning in Strelitzia , Volume 9, 2000, p. 713, the monotypical genera Androsiphon and Amphisiphon were incorporated into Daubenya . The last revision of the genus Daubenya was in John C. Manning & Alison M. van der Merwe: Systematics of the genus Daubenya (Hyacinthaceae: Massonieae) , In Bothalia , Volume 32, Number 2, 2002, pp. 133-150; species from the genus Massonia were placed in Daubenya .
The genus Daubenya belongs to the Subtribus Massoniinae from the tribe Hyacintheae in the subfamily of the Scilloideae within the family Asparagaceae . It was previously classified in the Hyacinthaceae or Liliaceae families.
There are about eight Daubenya species, here with occurrence and endangerment:
- Daubenya alba A.M. van der Merwe : This rare but not endangered species was first described in 2002. The range of this habitat specialist is small. It occurs only on the Roggeveld layer between Calvinia and Middelpos in the North Cape . It thrives in the Succulent Karoo on seasonally water-saturated, clayey soils over dolerite on flat hills or at the foot of rocky dolerite outcrops.
- Daubenya aurea Lindl. (Syn .: Massonia aurea (Lindl.) G.Don, Hort. Brit. , Massonia lutea Lindl. , Daubenya fulva Lindl. , Daubenya coccinea Harv. Ex Baker , Daubenya aurea var. Coccinea (Harv. Ex Baker) Marloth ): It occurs only on the Roggeveld layer between Sutherland and Middelpos in the North Cape . It thrives in the fynbos and in the succulent karoo in arid bushland, in seasonally humid locations, on red clay plains along the base of dolerite ridges. The very small habitats are currently threatenedby the expansion of arable farming and overgrazing . It is considered "endangered", although it is still common in some locations.
- Daubenya capensis (Schltr.) AMvan der Merwe & JCManning (Syn .: Androsiphon capensis Schltr. ): This endemic is only known from eight locations in the Bokkeveld strata and Western Karoo in the North Cape. The range of this habitat specialist is small. It thrives in fynbos and in the succulent Karoo on seasonally moist locations on clayey soils above dolorite. In the 1950s, 13% of its habitat was turned into fields of wheat. Intensive grazing takes place on the sites, but this species is not sensitive to grazing. It is considered to be “Near Threatened” because the stocks are stable.
- Daubenya comata (Burch. Ex Baker) JCManning & AMvan der Merwe (Syn .: Massonia comata Burch. Ex Baker , Polyxena comata (Burch. Ex Baker) Baker , Neobakeria comata (Burch. Ex Baker) Schltr. ): It is the most widespread Daubenya species and occurs in the Eastern Cape, Western Cape, Free State and the Northwest . It thrives in the Nama Karoo , grasslands and savannahs in seasonally water-saturated, loamy or clay soils. Their stocks are not diminishing and they are classified as “Least Concern” = “not at risk”.
- Daubenya marginata (Willd. Ex Kunth) JCManning & AMvan der Merwe (Syn .: Massonia marginata Willd. Ex Kunth , Polyxena marginata (Willd. Ex Kunth) Baker , Neobakeria marginata (Willd. Ex Kunth) Schltr. , Massonia rugulosa Licht. Ex Kunth , Polyxena haemanthoides Baker , Polyxena rugulosa (Licht. Ex Kunth) Baker , Neobakeria haemanthoides (Baker) Schltr. , Neobakeria rugulosa (Licht. Ex Kunth) Schltr. ): It is relatively widespread in the North Cape and Western Cape on the Roggeveld layer and western Karoo between Calvinia, Sutherland, Fraserburg and Loxton and has isolated populations on the Bokkeveld and Knersvlakte. This species thrives in the Succulent Karoo on seasonally moist hollows in silty or sandy loam. It is rated as “Least Concern” = “not at risk”.
- Daubenya namaquensis (Schltr.) JCManning & Goldblatt (Syn .: Neobakeria namaquensis Schltr. , Polyxena namaquensis (Schltr.) K.Krause ): It is a rare but not endangered species of which there are only small colonies whose populations on the small areas but are stable. This endemic is a habitat specialist in Namaqualand . It thrives in the Nama Karoo in deep red sand along drainage channels, in semi-arid plains east of Okiep and Springbok in the North Cape.
- Daubenya stylosa (WHBaker) AMvan der Merwe & JCManning (Syn .: Amphisiphon stylosus W.H.Baker ): This endemic is only known from three locations in the Bokkeveld layer in the North Cape. It thrives in the fynbos and in the succulent karoo on deep drains on clayey soils over dolerite. It is rated as "Vulnerable" = "at risk" and the stocks are considered stable. The endangerment comes from agriculture and grazing; around 17% of the originally very small area has already been lost.
- Daubenya zeyheri (Kunth) JCManning & AMvan der Merwe (Syn .: Massonia zeyheri Kunth , Massonia lanceolata Zeyh. Ex Kunth nom. Illeg., Massonia burchellii Baker , Massonia pedunculata Baker , Polyxena burchellii (Baker) Baker , Neobakeria burchellii (Baker) Schltr . ): This endemic is only known from ten locations in a very small area between Paternoster and Langebaan in the Western Cape. It thrives in fynbos mostly in coastal granite - rubble and sometimes on adjacent sandy areas and local stone . The populations are small, with the largest containing 500 and 1000 adult specimens. In total there are probably only 6500 specimens in nature. A constant loss of habitat occurs through coastal development. It is considered "Vulnerable" = "at risk" and stocks are decreasing.
swell
- John C. Manning, Peter Goldblatt & Dee Snijman: The color encyclopedia of Cape bulbs , Timber Press, Portland and Cambridge, 2002. ISBN 0-88192-547-0 : Eucomis on pp. 154–155 (sections description, distribution and systematics )
- John C. Manning: South Africa's Jewels of the Desert: A Reappraisal of the Genus Daubenya (Hyacinthaceae) , In: Herbertia , Volume 56, 2001, pp. 61-66. PDF.
- John C. Manning & Alison M. van der Merwe: Systematics of the genus Daubenya (Hyacinthaceae: Massonieae) , In Bothalia , Volume 32, Number 2, 2002, pp. 133-150. ( PDF )
Individual evidence
- ↑ a b c Rafaël Govaerts (ed.): Daubenya. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved October 29, 2014.
- ↑ a b c d e f g h i j John C. Manning, Peter Goldblatt, Dee Snijman: The color encyclopedia of Cape bulbs , Timber Press, Portland and Cambridge, 2002. ISBN 0-88192-547-0 : Daubenya on p 124-127.
- ↑ a b c d e f g h i j k l List of species for Daubenya in the Red List of South African Plants .
- ↑ First publication scanned at biodiversitylibrary.org .
- ↑ Daubenya at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed April 10, 2013.
- ^ A b Daubenya in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved April 10, 2013.
- ↑ Daubenya at the pacificbulbsociety . last accessed on October 29, 2014.
