Callianthe Donnell
Contenido
Descripción
Shrubs or treelets 1-8 m. tall, stems densely pubescent when young and minutely pubescent at maturity, the trichomes stellate or simple, rarely dendroid. Leaves simple, to 22 cm long and 19 cm wide, generally decreasing in size towards the stem apex. Stipules often early deciduous, linear, narrowly oblong or ovate, 0.3-1.5 cm long, 0.1-0.6 cm wide. Petioles 2-20 cm long, with the longer petioles on older parts of the plant. Lamina elliptic to broadly ovate (broadly obovate in species with lobed leaves), unlobed, shallowly 3-lobed or 5-7-lobed, basally cordate to lobate, rounded, cuneate, near-truncate or oblique, margins serrate-crenate to serrulate-crenulate or subentire (rarely dentate or entire), apex acute to acuminate, leaf surface stellate-pubescent, often more densely on abaxial surface; leaves sometimes discolorous, venation brochidodromous. Flowers solitary, paired or in clusters of 3 flowers, axillary, on pedicels to 10 cm long. Involucel absent. Calyces gamosepalous, 5-lobed, the lobes 1-4.5 cm, often heavily veined or keeled, the midvein prominent, minutely to densely stellate pubescent (sometimes dendroid, rarely simple), the indumentum often brown, tan or ferrugineous (rarely silvery-tan or white), the lobes ovate- lanceolate, free from the tube 2/8-7/8 of the way to the acute apex. Corolla rotate or campanulate, exceeding calyx in length, the petals obovate and often clawed at the base, 1.5- 5.5 cm long, 0.5-5 cm wide; red, white, cream, yellow, purple, lavender, pink, or burgundy, usually prominently veined, the veins sometimes of another color. Staminal column usually exserted but sometimes included, 0.7-5 cm long, glabrous. Carpels 8-14(-16), 4-13-ovulate. Styles equal in number to carpels, surpassing the anther mass by up to 1 cm or included. Stigmas capitate. Fruits schizocarpic, to 5 cm in diameter. Mericarps unilocular, sclerotic and brown to black at maturity, 1-4.8 cm long, sparsely to densely stellate- pubescent on outer wall, minutely stellate-pubescent on inner wall, dehiscing dorsally, the dorsal margin entire, subentire, apically cuspidate, or with a lacerate, wing-like projection. Seeds to 4 mm long, stellate pubescent or pilose. Base chromosome number: x = 8.A
Discusión taxonómica
The boundaries between the genera Bakeridesia and Abutilon have long been debated. Results from recent phylogenetic studies using the rDNA ITS in tribe Malveae strongly suggest that these two genera as currently delimited are polyphyletic. Some species previously included in each genus form a well-supported clade that is phylogenetically removed from both Bakeridesia and Abutilon. The congruence of morphological and karyological distinctions with this molecular evidence provides compelling support for recognition of the clade as a new genus, here described as Callianthe. Donnell et al., 2012 transfer 40 species to Callianthe based on ITS data (including the synapomorphy of a 25-base pair deletion in ITS2) and /or morphological evidence, including the character states of four or more ovules per carpel, toothed and /or lobed leaves, and petals with impressed veins (the latter is a synapomorphy). In addition, species of Callianthe share a base chromosome number of X = 8 (versus 7 in Abutilon and 15 in Bakeridesia). Not only is Callianthe phylogenetically removed from both Bakeridesia and Abutilon, but it is also morphologically distinct from its closest phylogenetic relative, Gaya, which has a base chromosome number of x = 6. Callianthe has a Neotropical distribution with a center of diversity in eastern Brazil. It includes all species previously referred to Bakeridesia subg. Dipteron and several large-flowered species previously referred to Abutilon.A