Herbs annual [biennial or perennial], chlorophyllous, glabrous. Leaves cauline, opposite, sometimes also basal. Inflorescences: flowers solitary at end of primary stem and branches (if any) [in small, sometimes racemelike cymes]. Flowers 4(–5)-merous; calyx deeply lobed, lobes often unequal; corolla violet-blue or greenish white [pale yellow], tubular-salverform [narrowly campanulate], adaxially with 2 fringed scales [1 continuous scale] near base of each lobe, lobes shorter than tube, margins entire or nearly so, plicae between lobes absent, spurs absent; stamens inserted near middle of corolla tube; anthers distinct, remaining straight; ovary sessile; styles persistent, erect, short or indistinct; stigmas 2, remaining straight; nectaries on corolla tube near base, 2 per petal. Capsules compressed-cylindric. x = 5, [6, 8, 9].

Distribution

North America, Eurasia, temperate to arctic and alpine areas.

Discussion

Species ca. 25 (1 in the flora).

Although Comastoma has much in common morphologically with Gentianella, molecular phylogenetic studies indicate that the origin of Comastoma was separate from that of Gentianella and place it closer to Lomatogonium (Yuan Y. M. and P. Küpfer 1995; K. B. von Hagen and J. W. Kadereit 2002). Palynological and embryological studies also indicate a separate origin (S. Nilsson 1967; Liu J. Q. and Ho T. N. 1996).

Comastoma tenellum differs distinctly from Gentianella species in the flora by its pedicels, which are generally longer than the subtending internodes.

Selected References

None.

Lower Taxa

Comastoma tenellum