keys to the vascular plants of east texas - Botanical Research ...

716 LEMNACEAE
1-celled; seeds 3 per capsule, 0.9–1.6 mm long, with whitish elaiosomes or caruncles (= appendages
used in dispersal by ants or other insects), ca. 1/3–2/3 length of seed.
AA genus of ca. 108 species (Swab 2000), nearly cosmopolitan in distribution but especially in
temperate Eurasia. Handel (1978) and Beattie and Culver (1981) presented experimental evidence
that the seeds of some species are dispersed by ants. The two TX taxa are sometimes treated as
varieties of a single variable species complex, L. campestre (e.g., Yatskievych 1999). (Derivation
uncertain; possibly either from Italian, lucciola, to shine or sparkle, or from Latin, gramen
luzulae, or luxulae, diminutive of Latin lux, light, a name given because hairs of several species
appear shiny when covered with dew—Swab 2000)
REFERENCE: Swab 2000.
1. Small bulb-like whitish structures (= swollen, reduced storage leaves) usually present on the
rhizomes; glomerules (= flower clusters) cylindric; perianth � equal to or shorter than capsule;
inflorescence branches usually erect or ascending _______________________________________ L. bulbosa
1. Small bulb-like structures not present on the rhizomes (but base of plant can be swollen); glomerules
subglobose or ovoid; perianth usually conspicuously longer than capsule; some of the
inflorescence branches usually divergent, sometimes to right angles ________________________ L. echinata
Luzula bulbosa (A.W. Wood) Smyth, (bulbose), BULB WOODRUSH. Stems in tufts or solitary, to 45
cm tall; rhizomes slender with whitish, swollen, bulb-like structures (= reduced storage leaves)
ca. 2–4 mm thick; leaves few, to 17 cm long, 2–7 mm wide, long-hairy marginally; perianth segments
(= tepals) 2–3 mm long, with shining chestnut centers and clear margins and apex; anthers
1–2 times as long as filaments; stigmas 3–4 times as long as styles. Sandy soils in forests,
sometimes in more open areas; Pineywoods and Post Oak Savannah w to Fannin Co. in Red
River drainage (Talbot property—BRIT); Turner et al. (2003) also mapped Hays Co. at w margin
of East TX and Tarrant Co. in the Cross Timbers and Prairies; e U.S. from CT s to GA w to KS
and TX. Spring. [L. campestris (L.) DC. var. bulbosa A.W. Wood]
Luzula echinata (Small) F.J. Herm., (prickly), HEDGEHOG WOODRUSH. Similar to L. bulbosa but
more densely tufted; rhizomes knotty and base of plant sometimes swollen, but rhizomes without
bulb-like structures; perianth segments (2.8–)3.5–4 mm long, greenish to pale or dark
brown, usually with clear margins and apex; anthers 2–5 times as long as filaments; stigmas 2–
3 times as long as styles. Sandy soils; Pineywoods and Post Oak Savannah w to Lamar Co. (Carr
1994) in Red River drainage; e U.S. w to IA and TX. Spring. [L. campestris (L.) DC. var. echinata
(Small) Fernald & Wiegand, L. echinata var. mesochorea F.J. Herm.]
LEMNACEAE Gray
DUCKWEED FAMILY
Very small or minute annual or perennial aquatic plants, floating free on or in the water, each
reduced to a small, green, flat or solid body (called thallus, frond, or joint) a few mm or less
across, not differentiated into stems and leaves, solitary or in small clusters; new plants (=
daughter fronds) chiefly produced asexually by budding, often remaining attached to the parent
frond by a short stipe; turions (= reduced, compact, starch-rich fronds, produced under unfavorable
conditions and overwintering underwater) sometimes produced; roots absent or
present and unbranched; flowering infrequent or at least infrequently observed; inflorescence
with 1 or 2 flowers, produced in 2 lateral pouches at frond base (in Lemna and Spirodela) or in a
cavity on frond surface (in Wolffia and Wolffiella); flowers minute, without perianth (a very
minute bract may be present); fruit a follicle with 1–5 seeds.
AA small (37 species in 5 genera—Les & Crawford 1999; Landolt 2000) family of aquatic
plants thought to be derived from the Araceae (JACK-IN-THE-PULPIT family). Members of the