4. Habenaria repens Nuttall, Gen. N. Amer. Pl. 2: 190. 1818.
Water-spider orchid, Floating orchid, water orchid
Habenaria nuttallii Small
Plants terrestrial or semiaquatic, erect to decumbent, 10–90 cm. Leaves scattered along stem and gradually reduced to sheathing bracts; blade ascending, linear-lanceolate to lanceolate, narrowly elliptic, or oblanceolate, 3–25 × 1–4.5 cm. Inflorescences: floral bracts spreading to ascending, lanceolate, 15–90 × 5–12 mm. Flowers ascending, not showy; sepals 3–7 × 3–4 mm; dorsal sepal shallowly concave; lateral sepals reflexed-spreading; petals greenish, lamina ascending, falcate, 3–7 × 1 mm, lateral lobe arcuately spreading-ascending, filiform, slightly to markedly exceeding petal; lip greenish, middle lobe descending, linear, 4–7 × 1 mm, lateral lobes ascending-spreading, filiform, 5–11 mm; spur slenderly cylindric to scarcely club-shaped, 0.8–1.4 cm; ovaries 9–15 mm. Capsules on short pedicel, nearly erect, 8–15 × 3–7 mm.
Flowering primarily summer--fall, sporadically (Apr--Dec). Marshes, wet meadows, bogs, margins of streams, ditches, and ponds; commonly an emergent aquatic in shallow water and in floating mats alone or with other vegetation; 0--100 m; Ala., Ark., Fla., Ga., La., Miss., N.C., Okla., S.C., Tex.; Mexico; West Indies; Central America; South America.
Habenaria repens is remarkable in sometimes being truly aquatic. Often forming floating mats, the plants then are commonly decumbent, at least basally, and new shoots and slender roots arise abundantly from much of the length of the stem. A few spheroid tuberoids are sometimes produced from roots arising at wide intervals. Other roots bear new shoots some decimeters from the parent stem; the distal portion of the root then commonly enlarges into a slenderly lance-fusiform tuberoid.