Oxypetalum coeruleum

Oxypetalum banksii

Oxypetalum is a plant genus in the subfamily of the milkweed family ( Asclepiadoideae ) within the family of the dogbane family ( Apocynaceae ). Currently, about 130 Oxypetalum species are recognized.

• 4.1 Notes and references

Description

Vegetative characteristics

The Oxypetalum species grow as self upright perennial, herbaceous plants or woody at the base slightly creeper. The Stems are hairless, tight fluffy shaggy or hairy.

The leaves arranged on opposite sides. The herbaceous leaf blades are linear, ovate or triangular with rounded or heart-shaped Spreitenbasis and abgestumpfem or sharpened with a length of 3 to 12 cm and a width of 1.5 to 7 cm. The leaf margin may be undifferentiated or slightly wavy, until fluffy hairy or shaggy.

Generative features

The individually outside the leaf axils standing inflorescence may be branched or brostrychoid sciadioidal and contains about 10 to 20 flowers. The inflorescence stem is about as long or longer than the pedicels. The hair ( Indument ) of the inflorescence stem and flower stems corresponds to the pubescence of the stem axis.

The buds are ellipsoidal or conical. The hermaphrodite flowers are radial symmetry and fünfzählig. The calyx is shorter or just as long as the corolla. The five sepals are fused at the base bell-shaped tip sharpened. The flower color varies from white, cream, green, yellow, brown, pink, reddish to bluish. The five petals are fused at 1 /4 to 3 /4 of the total length bell-shaped to urn -shaped. The corolla has a diameter of 5 to 15 mm. The shape of the petals ranging from lanceolate to ovate -sharpened, sometimes they are also rotated in itself. The gynostegiale corona consists of free staminal lobes, rarely from free interstaminalen corners. They are often grown together with crown and Gynostegium. The tail is erect, laminar or fleshy, lanceolate, oblong or nearly zovat, also divided into two parts. The interstaminale Nebenkrone is shorter than the staminal crown tip. The Gynostegium is stalked sessile or short. The dust bags are rectangular, the wings of the dust bag are approximately parallel over the entire length of the dust bag. The pollinia (pollen mass ) is ovoid, elongated and apically to the straight or slightly curved, cylindrical or flattened Caudikeln.

Most pairs, rare solitary follicles are spindle-shaped with a length of 50 to 100 mm and a diameter of 4 to 25 mm and include up to 50 seeds. Outside they are smooth or have longitudinal grooves on. The angle between the two individual fruits is less than 90 °. The long and wide have a length of 5 to 7 mm in diameter from 2.5 to 4 mm ovoid or pear-shaped, light to dark brown seeds can have a 0.4 to 0.8 mm wide, borderless union wing. The edge is smooth and serrated at apical or in some species also on the edge. The tufts of hair is 25 to 40 mm long.

The chromosome numbers be 2n = 18 ( Oxypetalum balansae and Oxypetalum solenoid ) or 22 ( 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.

System

According to some authors of plant encyclopedias (eg Armitage ) Oxypetalum supposed to be a junior synonym of Tweedia. However, the taxon is in recent academic work as a valid taxon maintained (see Nilda Marquete Ferreira da Silva, Jorge Fontella Pereira and Maria da Conceição Valente, 2007). According to Sigrid songs Schumann and Ulrich Meve (2006), the genus to contain up to 125 species; Rapini et al. (2003 ) indicate even approximately 130 species. Here are therefore called just a few examples ( type species, an ornamental plant, and the recently Marquete of Nilda Ferreira da Silva, Jorge Fontella Pereira and Maria da Conceição Valente revised species from southern Brazil ):

• Oxypetalum alpinum ( Vell. ) Fontella & E.A.Schwarz
• Oxypetalum appendiculatum Mart.
• Oxypetalum arachnoideum E.Fourn.
• Oxypetalum banksii R.Br. ex Schult. ( Type species ) ( with two subspecies banksii R.Br. Oxypetalum ex Schult. Subsp. Banksii and Oxypetalum banksii subsp. Corymbiferum ( E.Fourn. ) Fontella & C. Valente )
• Oxypetalum coeruleum ( D.Don ) Decne. ( Ornamental plant, usually performed under the name Tweedia coerulea / caerulea)
• Oxypetalum cordifolium ( Vent. ) Schltr. ( with three subspecies Oxypetalum cordifolium subsp. brasiliense ( Decne. ) Fontella & Goyder and Oxypetalum cordifolium ( Vent. ) Schltr. subsp. pedicellatum ( Decne. ) Fontella & Goyder )
• Oxypetalum costae Occhioni
• Oxypetalum glaziovianum Loes.
• Oxypetalum glaziovii ( E.Fourn. ) Fontella & Marquete
• Oxypetalum insigne ( Decne. ) Malme
• Oxypetalum jacobinae Decne.
• Oxypetalum lanatum Decne. ex E.Fourn.
• Oxypetalum lutescens E.Fourn.
• Oxypetalum molle Hook. & Arn.
• Oxypetalum pachyglossum Decne.
• Oxypetalum pannosum Decne.
• Oxypetalum patulum E.Fourn.
• Oxypetalum pilosum Gardner
• Oxypetalum regnellii ( Malme ) Malme
• Oxypetalum schottii E.Fourn.
• Oxypetalum sublanatum Malme
• Oxypetalum wightianum Hook. & Arn.

Swell

• Sigrid songs 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: Asclepiasoideae ( Apocynaceae ) from southeastern Brazil. I. The genus Oxypetalum from Rio de Janeiro State, Brazil. Annals of the Missouri Botanical Garden, 94: 435-462, 2007 Full 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