Introduction
Calyptraemalva is a poorly known monotypic genus of Malvaceous herbs, endemic to southern Brasil
Classification
The sole species, C. catharinensis Krapov., from the Brasilian state of Santa Catarina, was described by Krapovickas in 1965.
The genus is placed in Malveae, close to Sphaeralcea and allied genera. However it is poorly known (for example, the fruits have not been described), and this placement may not be correct. (It is already known from DNA sequence evidence that not all genera placed close to Sphaeralcea actually are close to Sphaeralcea.)
The name refers to the presence of a calyptra enclosing the flower bud; this character is unique to this genus, in Malvoideae, and is rare elsewhere amongst angioserms.
The generic name has also been spelt as Calyptrimalva.
Calyptraemalva catharinensis Krapov.
C. catharinensis is remarkable for the presence of a calyptra, which in this case is a structure, presumed to be homologous to the epicalyx of other genera, which completely encloses in flower bud, apart from an apical pore. This is torn open by the developing bud and flower, leaving irregular remnants at the base of the calyx. It also shows another feature unusual in mallows - the presence of a small deciduous bract part way along the long pedicel.
Otherwise C. catharinensis is a shrub with reddish stems. The young stems are covered by a ferruginous pubescence and become glabrous with age. The leaves are simple, 3- or less commonly 5-veined, basally entire and distally weakly serrate. The stipules are pubescent, falcate (sickle-shaped) in shape, and 6-9 mm in length. The rose-coloured flowers are borne solitarily in the leaf axils. The pedicel and epicalyx are as above. The campanulate calyx is hirsute. It is about 2.5 cm long, and the upper half is divided into triangular lobes which are about 1 cm wide at the base. The corolla is about 4 cm long, with broadly clawed, obovate petals. The androecium is about 2 cm long, and bears numerous anthers on the upper portion of the pilose staminal column. The style is divided into 45 branches (more than any other genus of Malveae); these are slender, with capitate stigmas. The ovary locules are arranged in a single whorl. They are uniovulate. The fruits were not observed by Krapovickas, and I am unaware of any later observations. If the genus is correctly placed in Malveae the fruits can be assumed to be composed of up to 45 single-seeded mericarps. It is possible that the mericarps do not form a single whorl - compare Palaua, which also has a high number of style branches (30-40) and in which the mericarps are irregularly arranged in a subglobose head.
If you have found any errors on this page, or have any further information about the genus Calyptraemalva then please contact me at botany@malvaceae.info.
© 2003 Stewart Robert Hinsley