Isometrum

Full name and orig. publication: Isometrum Craib, Notes Roy. Bot. Gard. Edinburgh 11: 250 (Nov. 1919).

Etymology: From the Greek ίσος, isos = equal, and μετρον, metron = measure, measurement, dimension, size. The name alludes to the nearly equal corolla lobes.

Synonyms: - 

Infrafamilial position: Didymocarpoid Gesneriaceae - "Advanced Asiatic and Malesian genera" (Weber 2004).

Description: Perennial rosette herbs with short vertical rhizome. Leaves sessile or petiolate, undivided or pinnately lobed, usually hairy on both sides. Cymes with few to several flowers, pedunculate, peduncle and pedicels brown villose and glandular pubescent, rarely without glandular hairs; bracteoles 2, small. Sepals free to base, equal in size. Corolla tubular or campanulate, pale purple, sanguineous or blue-purple, limb bilabiate, upper lip 2-lobed, lower lip 3-lobed, lobes rounded. Stamens 4, didynamous, included; filaments inserted near base of corolla tube; anthers coherent, thecae divergent; staminode 1. Nectary annular, entire or 5-lobed. Ovary short-cylindrical; style equal or shorter than ovary; stigma bilobed. Capsule slender cylindrical or oblanceolate, glabrous or pubescent.

Chromosome number: Unknown.

Species number: 14.

Species names (incl. publication and synonyms): See Skog, L.E. & J.K. Boggan. 2005: World checklist of Gesneriaceae: http://persoon.si.edu/Gesneriaceae/Checklist.

Type species: Isometrum farreri Craib

Distribution: C China (Sichuan, Gansu, Hubei, Shaanxi). 

Ecology: Growing in forests, on rock cliffs, along trails and roadsides, and in rock crevices in moist, shaded places; 500-2000(-3900m).

Notes: Burtt, Notes Roy. Bot. Gard. Edinburgh 33: 91-93 (1960); Pan, Acta Bot. Yunnan. 8: 23-36 (1986), Acta Phytotax. Sin. 26: 432 (1988), rev.; Wang et al. in Wu & Raven (eds.), Fl. China 18: 263-267 (1998).

Selected references: Wiehler

Bibliography: See Skog, L.E. & J.K. Boggan. 2005. Bibliography of the Gesneriaceae. 2^nd edition: http://persoon.si.edu/Gesneriaceae/Bibliography.

Illustrations:

Isometrum farreri Craib, type species Ying T.S. et al., The endemic genera of seed plants in China, Fig. 117 (1993); with permission.

Isometrum primuliflorum (Batalin) B.L.Burtt Li Z.Y & Wang Y.Z., Plants of Gesneriaceae in China, Fig. 1.38 (2004); with permission.

last modified: 2007-07-13