Gomphocarpus
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Gomphocarpus fruticosus , flower |
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Gomphocarpus is a plant genus in the subfamily of asclepiadoideae (Asclepiadoideae). The distribution area originally includes eastern and southern Africa as well as isolated occurrences in higher areas in West Africa .
description
Appearance
Most Gomphocarpus TYPES grow as upright, woody at the base or perennial , herbaceous plants and reach stature heights of 50 to 300 centimeters. They have an abundant flowing white milky sap .
The stems that are more or less strongly branched or unbranched at the base or further up are stiff or flexible. One species has photosynthetically active stems (and reduced leaves). The stems are hollow in some species, some species produce annually stems from that of a fibrous or woody mostly non-tuberous rhizome or tap root sprout. The stems are glabrous or become glabrous with age or are downy, tomentose or hairy over the entire surface.
Foliage leaves
The opposite or occasionally whorled, slightly to strongly pointing upward leaves are sessile or very short stalked. The herbaceous to fleshy or leathery leaf blades are 3 to 12 (to 18) cm long and 0.3 to 2 (to 6) cm wide, linear, elongated, triangular to ovoid with a truncated or wedge-shaped or heart-shaped blade base and a pointed end, as well as mostly with downwardly bent leaf margins. They are weakly to very downy, tomentose or woolly hairy with long and soft trichomes , sometimes bald on top.
Inflorescence and flowers
The single, extra-axillary, overhanging inflorescences that protrude above the neighboring leaves usually contain 4 to 15 flowers (exceptionally also up to 30 flowers), which are arranged from simple to sciadioid (pseudo-umbel-shaped, derived from a screw through the reduction of the rachis ) . The fluffy to woolly hairy inflorescence shafts are just as long as the flower stalks. The flowers hang or point to the side. The buds are spherical or flattened ovoid.
The hermaphrodite flowers are radially symmetrical and five-fold. The calyx reaches about a quarter to half the length of the crown and has five or more glands. The five sepals are free, very hairy and ovate to lanceolate or triangular and pointed at the end. The five protruding to turned back, ciliate to bearded petals vary in length from 8 to 10 mm; they are egg-shaped, pointed at the end and only fused at the base. Their color ranges from white or cream to greenish, yellowish and brownish, often with a purple tinge. The gynostegial secondary crown varies in color from white to ivory, yellow or even purple (green to yellowish shades also occur). It consists of the very small interstaminal corolla lobes near the base of the anthers and the relatively large staminal corolla lobes. The secondary corolla are hood-shaped and can have a "tooth" or several extensions on the upper edge; however, the tooth (or horn) is usually missing in the hood-shaped cavity as it is, for example. B. is present in the genus Asclepias . The gynostegium is seated or sits on a short column. The scar is flattened. The anthers are rectangular and taller than wide. The edges are straight, or also slightly convex or concave. The wing-shaped widened edges of neighboring anthers run approximately parallel to one another. The brown or black colored corpusculum, a structure that connects two pollinia, is egg-shaped to almost cylindrical. The pollinia are flattened, oblong, obscure-lanceolate or obovate, sometimes inverted-triangular. The flowers produce a lot of nectar .
Fruits and seeds
The individual, upright, sometimes strongly inflated follicles standing on mostly twisted stems are 2 to 8 cm long with a diameter of 2 to 5 cm, in the direction of growth ellipsoidal to obverse-club-shaped, in cross-section ovoid to twisting. Their tips are more or less beaked, or pointed or blunt. The green to light brown follicles have a smooth or more or less densely covered surface with 5 to 10 mm long attachments ("soft thorns"). The 5 to 7 mm long and 2 to 5 mm wide, pear-shaped to egg-shaped or round, dark brown seeds have a 30 to 50 mm long head of hair and sometimes narrow, whole-edged wings.
Chromosome number
The number of chromosomes is 2n = 22 (in Gomphocarpus cancellatus , Gomphocarpus filiformis . And Gomphocarpus fruticosus ).
Occurrence
The original distribution area of the genus Gomphocarpus is eastern and southern Africa as well as isolated occurrences in higher areas in West Africa (e.g. Jebel Marra , western Sudan , northern Cameroon and the Dalaba plateau in Guinea ). In the north, the distribution area extends to the Sinai Peninsula , the Dead Sea region and the Arabian Peninsula .
Individual Gomphocarpus species (for example Gomphocarpus fruticosus and Gomphocarpus physocarpus ) are used as ornamental plants and are nowadays neophytes that have grown wild almost worldwide in suitable habitats . So Gomphocarpus cornutus became Decne. Described from Madagascar in 1838, Gomphocarpus arachnoideus E. Fourn. 1867 from Mexico, both of which, as later showed, are synonyms of Gomphocarpus fruticosus (L.) WTAiton and thus show the very early displacement of this species. Finally, in 1868, Gomphocarpus fruticosus was detected in Australia together with Gomphocarpus physocarpus . Another species, Gomphocarpus cancellatus , has been firmly established in the two Australian states of South Australia and Victoria since the 1990s at the latest .
The vast majority of Gomphocarpus species grow as pioneer plants on fallow land. The species group around Gomphocarpus glaucophyllus and Gomphocarpus purpurascens occur on areas that are susceptible to bush fires . Some other species are also considered to be facultative rheophytes ; H. Plant species that successfully colonize sand, gravel and gravel banks of rivers as pioneer plants. The only real rheophyte is Gomphocarpus rivularis .
Systematics
The genus Gomphocarpus was established in 1810 by Robert Brown in Memoirs of the Wernerian Natural History Society , 1 (preprint), p. 37. The generic name is made up of the ancient Greek words γόμφος = gomphos for screw, nail, tooth, peg and κάρπος = karpos for fruit. Type species is Asclepias fruticosa L. The genus Gomphocarpus belongs to the subtribe Asclepiadinae from the tribe Asclepiadeae in the subfamily Asclepiadoideae within the family Apocynaceae .
According to Goyder & Nicholas 2001, the genus Gomphocarpus contains 20 species:
- Gomphocarpus abyssinicus Decne. : It occurs in Guinea, Cameroon and from Sudan to Eritrea.
- Gomphocarpus cancellatus (Burm. F.) Bruyns : It occurs from Namibia to South Africa.
- Gomphocarpus filiformis (E.Mey.) Dietr. : It occurs from Namibia to South Africa.
- Gomphocarpus fruticosus (L.) WTAiton (Syn. Asclepias fruticosa L. ): It occurs in five subspecies from Eritrea to South Africa and on the Arabian Peninsula.
- Gomphocarpus glaucophyllus Schltr. : It occurs from Uganda to Swaziland.
- Gomphocarpus integer (NEBr.) Bullock : It occurs from northeastern tropical Africa to northern Tanzania.
- Gomphocarpus kaessneri (NEBr.) Goyder & Nicholas : It occurs from southern Kenya to northern Zambia.
- Gomphocarpus munonquensis (S.Moore) Goyder & Nicholas : It occurs in western Tanzania and in southeastern Angola.
- Gomphocarpus phillipsiae (NEBr.) Goyder : It occurs from Eritrea to Tanzania.
- Gomphocarpus physocarpus E. Mey. (Syn .: Asclepias physocarpa (E.Mey.) Schltr. ): It occurs from southern Mozambique to southern Africa.
- Gomphocarpus praticola (S.Moore) Goyder & Nicholas : It occurs from western Tanzania to southern tropical Africa.
- Gomphocarpus purpurascens A.Rich. : It occurs from Eritrea to Ethiopia.
- Gomphocarpus rivularis Schltr. : It occurs in southern Africa.
- Gomphocarpus semiamplectens K.Schum. : It occurs from the Democratic Republic of the Congo to northern Namibia.
- Gomphocarpus semilunatus A.Rich. : It occurs from Nigeria to Ethiopia and Zambia.
- Gomphocarpus sinaicus Boiss. : It occurs from Israel to the north-central and western Arabian Peninsula.
- Gomphocarpus stenophyllus olive. : It occurs from southern Ethiopia to Tanzania.
- Gomphocarpus swynnertonii (S.Moore) Goyder & Nicholas : It occurs from Zaire and Tanzania to southern tropical Africa.
- Gomphocarpus tenuifolius (NEBr.) Bullock : It occurs in Zimbabwe.
- Gomphocarpus tomentosus Burch. : It occurs in two subspecies from southern Africa to southern tropical Africa.
Differences to the related genus Asclepias
The genus Gomphocarpus differs from the genus Asclepias mainly in the fibrous or woody rhizome , which in Asclepias is slim to thick beet-shaped or bulbous. Gomphocarpus forms short-lived, perennial subshrubs with branched stems, while Asclepias forms annually new, mostly unbranched or slightly branched stems. Furthermore, the inflorescences of Gomphocarpus are extra-axillary (arising from the leaf axils ), whereas in Asclepias they are terminal.
swell
- DJ Goyder, A. Nicholas: A Revision of Gomphocarpus R. Br. (Apocynaceae: Asclepiadeae). In: Kew Bulletin. Vol 56, No. 4, 2001, pp. 769-836, JSTOR 4119297 .
- S. Liede-Schumann, U. Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae (Apocynaceae) Descriptions, Illustrations, Identification, and Information Retrieval. Gomphocarpus - online, version dated September 21, 2000.
- Bingtao Li, Michael G. Gilbert, W. Douglas Stevens: Gomphocarpus . In Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . tape 17 : Verbenaceae through Solanaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1994, ISBN 0-915279-24-X , pp. 204 (English). , PDF file , online.
Individual evidence
- ^ Gomphocarpus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- ↑ a b c d e f g h i j k l m n o p q r s t Rafaël Govaerts (Ed.): Gomphocarpus - World Checklist of Selected Plant Families des Royal Botanic Gardens, Kew. Last accessed on November 5, 2017.
