Oxypetalum
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Oxypetalum is a genus of plants in the subfamily of the silk plant family (Asclepiadoideae) within the family of the dog venom plants (Apocynaceae). About 130species of Oxypetalum are currentlyrecognized.
description
Vegetative characteristics
The Oxypetalum species grow as independently upright perennial , herbaceous plants or as slightly woody climbers at the base . The shoot axes are hairless, dense, downy or shaggy.
The leaves are arranged opposite one another. The herbaceous leaf blades are linear, egg-shaped or triangular with a heart-shaped base and a rounded or truncated or pointed end with a length of 3 to 12 cm and a width of 1.5 to 7 cm. The leaf margin can be undifferentiated or slightly wavy, hairy to downy or shaggy.
Generative characteristics
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The inflorescence standing individually outside the leaf axils can be brostrychoid or sciadioidal and contains about 10 to 20 flowers. The inflorescence stem is about as long or longer than the flower stalks. The hairiness ( indument ) of the inflorescence stem and the flower stalks corresponds to the hairiness of the stem axis.
The buds are ellipsoidal or conical. The hermaphrodite flowers are radially symmetrical and five-fold. The calyx is shorter or as long as the corolla. The five sepals are fused bell-shaped at the base with a pointed end. The color of the flower varies from white, cream, green, yellow, brown, pink, reddish to bluish. The five petals are fused bell-shaped to urn-shaped over ¼ to ¾ of the total length. The corolla has a diameter of 5 to 15 mm. The shape of the petals ranges from lanceolate to ovate with a pointed end, occasionally they are also twisted. The gynostegial secondary crown consists of free staminal lobes, more rarely free interstaminal lobes. They are often fused with the crown and gynostegium . The tips are erect, laminar or fleshy, lanceolate, elongated or approximately ovate, also divided into two. The interstaminal corolla is shorter than the staminal corolla lobes. The gynostegium is seated or has a short stalk. The dust bags are rectangular, the wings of the dust bags run approximately parallel over the entire length of the dust bag. The pollinium (pollen mass) is egg-shaped, elongated and apical on the straight or slightly curved, cylindrical or flattened caudicles .
The mostly paired, rarely individually standing follicles are spindle-shaped with a length of 50 to 100 mm and a diameter of 4 to 25 mm and contain up to 50 seeds. Outside they are smooth or have longitudinal pits. The angle between the two individual fruits is less than 90 °. With a length of 5 to 7 mm long and a diameter of 2.5 to 4 mm wide, the egg or pear-shaped, light to dark brown seeds can have a 0.4 to 0.8 mm wide, marginal wing. The edge is smooth and serrated at the apical end or, in some species, over the entire edge. The tuft of hair is 25 to 40 mm long.
Chromosome numbers
The number of chromosomes is 2n = 18 in Oxypetalum balansae or Oxypetalum solanoides and 2n = 22 in Oxypetalum ostenii .
Occurrence
The Oxypetalum species occur in South America (Argentina, Bolivia, Brazil, Ecuador, Paraguay, Peru, Uruguay and Venezuela). They grow there in forests and open, little-changed areas.
Systematics
According to some authors of plant encyclopedias (e.g. Armitage), Oxypetalum is said to be a younger synonym of Tweedia . However, the taxon is maintained as a valid taxon in more recent scientific work (cf. Nilda Marquete Ferreira da Silva, Jorge Fontella Pereira and Maria da Conceição Valente, 2007). According to Sigrid Liede-Schumann and Ulrich Meve (2006) the genus should contain up to 125 species; Rapini et al. (2003) even give about 130 species. At WCSP (as of November 2018) there are 133 species. Type species of the genus is Oxypetalum banksii R.Br. ex Schult.
Therefore, only a selection of species is mentioned here:
- Oxypetalum alpinum (Vell.) Fontella & E black : It occurs in southern Brazil.
- Oxypetalum appendiculatum Mart. : It occurs from Bolivia to Brazil and northeast Argentina.
- Oxypetalum arachnoideum E. Fourn. : It occurs in Brazil.
- Oxypetalum arnottianum H.Buek : It occurs in Bolivia, Brazil, Argentina, Paraguay and Uruguay.
- Oxypetalum balansae Malme : It occurs from Bolivia to Brazil and northern Argentina.
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Oxypetalum banksii R.Br. ex Schult. : It occurs in Brazil with two subspecies:
- Oxypetalum banksii subsp. banksii
- Oxypetalum banksii subsp. corymbiferum ( (E. Fourn.) Fontella & C. Valente ):
- Oxypetalum coeruleum (D.Don) Decne. (Ornamental plant, usually under the name Tweedia coerulea or Tweedia caerulea ): It is originally found in Brazil and Uruguay.
- Oxypetalum commersonianum (Decne.) Fontella & E black : It occurs in southern Brazil, Uruguay and northeastern Argentina.
- Oxypetalum cordifolium (Vent.) Schltr. (with four sub-types: Oxypetalum cordifolium subsp. brasiliense (Decne) Fontenella & Goyder. , Oxypetalum cordifolium subsp. pedicellatum (Decne) Fontenella & Goyder. , Oxypetalum cordifolium subsp. mexiae (Malme) Fontenella & Goyder and Oxypetalum cordifolium subsp. cordifolium ): It occurs from Mexico to tropical South America and the islands of the Caribbean.
- Oxypetalum costae Occhioni : It occurs in the Brazilian state of Rio de Janeiro.
- Oxypetalum crispum Wight ex Hook. & Arn. : It occurs in Bolivia, southern Brazil, Uruguay, Paraguay and northeastern Argentina.
- Oxypetalum erectum Mart. : It occurs from Bolivia to Brazil.
- Oxypetalum glaziovianum Loes. : It occurs in the Brazilian state of Rio de Janeiro.
- Oxypetalum glaziovii (E. Fourn.) Fontella & Marquete : It occurs in southeastern Brazil.
- Oxypetalum harleyi (Fontella & Goyder) Farin. : It occurs in northeastern Brazil.
- Oxypetalum insigne (Decne.) Malme : It occurs in southern and southeastern Brazil.
- Oxypetalum jacobinae Decne. : It occurs in Brazil.
- Oxypetalum lanatum Decne. ex E. Fourn. : It occurs in Brazil.
- Oxypetalum lutescens E. Fourn. : It occurs in the Brazilian state of Rio de Janeiro.
- Oxypetalum macrolepis (Hook. & Arn.) Decne. : It occurs in southern Brazil, Paraguay, Uruguay and northeastern Argentina.
- Oxypetalum molle hook. & Arn. : It occurs from Brazil to Argentina.
- Oxypetalum ostenii HMalme : It occurs in southern Brazil and Argentina.
- Oxypetalum pachyglossum Decne. : It occurs from Brazil to Paraguay.
- Oxypetalum pannosum Decne. : It occurs from southern and southeastern Brazil to northeastern Argentina.
- Oxypetalum patulum E. Fourn. : It occurs in the Brazilian state of Minas Gerais .
- Oxypetalum pilosum Gardner : It occurs in southeastern Brazil.
- Oxypetalum regnellii (Malme) Malme : It occurs in southeastern Brazil.
- Oxypetalum schottii E. Fourn. : It occurs in the Brazilian state of Rio de Janeiro.
- Oxypetalum solanoides Hook. & Arn .: It occurs from Brazil and Uruguay to northeast Argentina.
- Oxypetalum sublanatum Malme : It occurs from southern and southeastern Brazil to Argentina.
- Oxypetalum wightianum Hook. & Arn. : It occurs in Brazil, Paraguay and Argentina.
swell
- Sigrid Liede-Schumann & Ulrich Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae (Apocynaceae) - Oxypetalum R. Br. (Asclepiadeae). Online status 2006.
- Nilda Marquete Ferreira da Silva, Jorge Fontella Pereira and Maria da Conceição Valente: Asclepiadoideae (Apocynaceae) from southeastern Brazil. I. The genus Oxypetalum from Rio de Janeiro State, Brazil. Annals of the Missouri Botanical Garden, 94: 435-462, 2007 Entire text .
- Alessandro Rapini, Mark W. Chase, David J. Goyder and Jayne Griffiths: Asclepiadeae Classification: Evaluating the Phylogenetic Relationships of New World Asclepiadoideae (Apocynaceae). Taxon, 52 (1): 33-50, 2003 abstract
Individual evidence
- ^ Allan M. Armitage Armitage's garden annuals: a color encyclopedia
- ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag Rafaël Govaerts (Ed.): Oxypetalum - World Checklist of Selected Plant Families des Royal Botanic Gardens, Kew. Last accessed on November 8, 2018.
- ↑ DJ Goyder: Philibertia barbata Apocynaceae: Asclepiadoideae. In: Curtis's Botanical Magazine , 25 (3), 2008, pp. 245-249. doi : 10.1111 / j.1467-8748.2008.00626.x
