Xyris difformis

Chapman

Fl. South. U.S. 500. 1860.

Treatment appears in FNA Volume 22.
Revision as of 20:59, 16 December 2019 by FNA>Volume Importer

Herbs, perennial, cespitose, (10–)15–70(–90) cm, base not bulbous. Stems compact. Leaves in narrow to broad fans, 5–50 cm; sheaths soft, base reddish; blade deep green, linear to linear—sword-shaped, flat, not twisted, under 7 mm wide, papillate or smooth, margins smooth or papillate, somewhat scabrous. Inflorescences: scape sheaths exceeded by leaves; scapes linear to filiform, terete proximally, terete or ancipital-2-edged–winged distally, 0.5–3 mm wide, variably ribbed, distally with 3 or more somewhat scabrous ribs, ribs papillate to scabrous; spikes prevalently ovoid, 5–20 mm, apex usually acute; fertile bracts (4–)5–7(–9) mm, margins entire, apex rounded. Flowers: lateral sepals included, slightly curved, 5–7 mm, keel brown, scarious, lacerate; petals unfolding in morning, blade obtriangular, 4 mm; staminodes bearded. Seeds translucent to mealy, ovoid to ellipsoid, 0.5 mm, finely lined longitudinally with small papillae.

Distribution

V22 390-distribution-map.jpg

North America, Central America.

Discussion

Varieties 3 (3 in the flora).

Selected References

None.

Key

1 Leaves and scapes (except for edges and ribs) smooth; scapes somewhat to much widened distally; 2 ribs comparably wider, making wings, smooth or papillate; seeds translucent Xyris difformis var. difformis
1 Leaves and scapes variously papillate or minutely scabrous; scapes not much widened distally; ribs all equally prominent, somewhat scabrous; seeds translucent or mealy. > 2
2 Seeds translucent; leaves spreading-ascending in broad fans, rarely as long as 10 cm, linear–sword-shaped; spikes rarely longer than 5 mm. Xyris difformis var. curtissii
2 Seeds mealy; leaves ascending in broad to narrow fans, rarely shorter than (10–)15 cm, linear; spikes 6–10(–15) mm Xyris difformis var. floridana