Microstachys

Herbs [shrubs], annual [perennial], monoecious; hairs unbranched [branched]; latex white. Leaves alternate, simple; stipules present, persistent; petiole present, glands absent; blade unlobed, margins serrulate [entire], laminar glands abaxial, at base [absent]; venation pinnate. Inflorescences appearing unisexual (pistillate and staminate portions usually shortly separated on stem), terminal, leaf-opposed, or axillary, racemelike thyrses; glands subtending each bract [0] 2. Pedicels present, often rudimentary. Staminate flowers: sepals 3, imbricate, distinct [connate basally]; petals 0; nectary absent; stamens 3, distinct; pistillode absent. Pistillate flowers: sepals 3, distinct; petals 0; nectary absent; pistil 3-carpellate; styles [0 or]3, connate basally, unbranched. Fruits capsules, base not persisting. Seeds oblong, ends truncate [elliptic]; outer seed coat dry; caruncle present [absent].

Distribution

Mexico, West Indies, Central America, South America, Asia, Africa, Australia, tropical and subtropical regions.

Discussion

Species ca. 15 (1 in the flora).

Microstachys is distinct based on morphology and molecular phylogenetic evidence (H.-J. Esser 1998; K. Wurdack et al. 2005), although species have been included historically in Sebastiania. The inflorescence architecture characteristic of Microstachys is unusual: the pistillate and staminate parts are usually shortly separated along the main stem, appearing as two separate partial inflorescences at consecutive nodes, the pistillate one proximal and supra-axillary, and the staminate distal and leaf opposed. The genus is known primarily from the New World with a few species found in Africa, Asia, and Australia.

Selected References

None.

Lower Taxa

Microstachys corniculata