Rhodora 30: 23. 1928.

Common names: Northern comandra false toadflax
Etymology: Greek ge, earth, and kaulos, stalk, alluding to slightly subterranean and stemlike rhizome
Treatment appears in FNA Volume 12. Treatment on page 411. Mentioned on page 408, 409.

Herbs, perennial, andromonoecious. Rhizomes not woody, reddish to dark brown, cortex smooth, not exfoliating. Leaves: petiole short. Inflorescences axillary (appearing terminal in early developmental stages but occupying middle axils with continued growth of main axis), cymules; cymules mostly 3-flowered; prophyllar bracteole subtending each flower caducous. Pedicels present. Flowers bisexual and staminate (central flower, or rarely 2 flowers, of dichasium usually bisexual, sometimes staminate, laterals staminate), campanulate to turbinate; hypanthium completely adnate to ovary; petals (4–)5, greenish to bronze (bisexual and unisexual flowers often differing in color), triangular or ovate; nectary nearly flat, lobes prominent, alternating with filaments; styles short-conic; stigmas slightly lobed. Pseudodrupes usually solitary; petal remains vestigial at apex; exocarp fleshy.


North America.


Species 1.

Geocaulon is one of only two genera named by M. L. Fernald (the other being Alcoceria, Euphorbiaceae, now treated as a synonym of Dalembertia Baillon). Fernald stated that many features of Geocaulon are similar to Nestronia (Santalaceae); however, molecular data clearly indicate that Geocaulon is sister to Comandra.

Selected References


Lower Taxa