Rhigospira

Rhigospira is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1878 by John Miers.^[2] The species, Rhigospira quadrangularis was first described as Ambelania quadrangularis by Johannes Müller Argoviensis in 1860^[3] but was transferred to the genus, Rhigospira, in 1878 by John Miers.^[4] The genus contains only one known species, Rhigospira quadrangularis, native to northwestern South America (Colombia, Venezuela, Peru, NW Brazil).^[5][6]

formerly placed in the genus^[5]

• Rhigospira paucifolia (Müll.Arg.) Miers = Macoubea guianensis Aubl.
• Rhigospira reticulata (A.DC.) Miers = Macoubea guianensis Aubl.
• Rhigospira sinuosa Miers = Macoubea guianensis Aubl.
• Rhigospira sprucei (Müll.Arg.) Miers = Macoubea sprucei (Müll.Arg.) Markgr.
• Rhigospira ternstroemiacea (Müll.Arg.) Miers = Neocouma ternstroemiacea (Müll.Arg.) Pierre
• Rhigospira venulosa Miers = Spongiosperma macrophyllum (Müll.Arg.) Zarucchi

Rhigospira
A. Rhigospira quadrangularis, portion of a plant. Fig. 1, the inflorescence. Fig. 2, a flower: both natural size. Fig. 3, the corolla in bud, showing the pyramidal form of the erect segments in aestivation. Fig. 4, the same cut open when expanded, showing their simple sinistrorse convolution and the nearly basal position of the stamens: both magnified. Fig. 5, the calyx, disk, very short style, clavuncle, and stigmata, natural size. Fig.6, the same, magnified. Fig. 7, a stamen, much magnified.[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Gentianales
Family:	Apocynaceae
Subfamily:	Rauvolfioideae
Tribe:	Tabernaemontaneae
Subtribe:	Ambelaniinae
Genus:	Rhigospira Miers
Species:	R. quadrangularis
Binomial name
Rhigospira quadrangularis (Müll.Arg.) Miers
Synonyms[2]
Ambelania quadrangularis Müll.Arg. Hancornia macrophylla Spruce ex Müll.Arg.