Duration: Perennial

Nativity: Native

Lifeform: Forb/Herb

General: Aquatic or semiaquatic perennial herb from rhizomes 0.6-4.5 mm in diameter.

Leaves: Borne individually or in clusters along horizontal rhizomes or in clusters at the apex of vertical rhizome branches, round or elliptical in cross section, linear or tapering continually from the base, 2.5-33.0 (-50.0) cm long, 0.5-5.5 mm broad, 6-13 (-18)-septate, narrowly rounded at the apex, expanded at the base into a scarious sheath 0.3-2.3 cm long.

Flowers: Peduncles 4-55 mm long, shorter than the leaves; involucral bracts 0.5-3.5 mm long; umbels 3-10-flowered; pedicels 1-13 mm long; petals maroon-tinted.

Fruits: Generally globose or ellipsoid, occasionally ovoid to obovoid, 1.2-2.3 mm long, 1.3-2.1 (-2.3) mm broad, with spongy cells present in all 5 ribs of the mericarp, the lateral ribs rounded, the dorsal and intermediate ribs rounded or broadly triangular in c

Ecology: Found in shallow water along damp margins of lakes, streams, rivers, pools, ditches, springs and cienega wetlands; 2,000-7,060 ft (610-2,170 m); flowering March-October, with peak flowering in July.

Distribution: Known only from southeastern Arizona and n MEX; in Cochise, Pima, and Santa Cruz counties; with a few populations in Chihuahua and Sonora.

Notes: A rare and endangered species very easy to miss in the field, at first glance, may appear as a grass or monocot due to its diminutive appearance and the thin, linear leaves. It can occur in thick patches in wet areas though, or even submerged in water. It is distinguished by its small size, rhizomotous habit and the cylindrical, hollow leaves with septa (internal horizontal divisions forming chambers), which hold oxygen and are an adaptation to the partially submerged, aquatic lifestyle. The tiny flowers are borne in umbels which are always shorter than the leaves. Listed as endangered due to very few populations along stream-side, pool-side, spring and cienega wetlands; many of which have seen a decrease in the last century and in some locations completely disappearing. Many of the historic occurrences and collection localities are now considered extirpated, and threats are considered very high due to the continuing lowering of water tables in many locations.

Ethnobotany: Unknown

Etymology: Lilaeopsis is from the Greek like Lilaea.

Synonyms: Lilaeopsis recurva

Editor: FSCoburn 2015