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

490 COMMELINACEAE/COMMELINA
the pedicels 0.5–1.5 mm long; petals all � similar, translucent white, lanceolate to narrowly oblong,
without an expanded blade, 3–5(–6) mm long, inconspicuous; stamens 0–6, sometimes 1
or more staminodial, exserted; filaments glabrous; stigma bushy; capsules 2-locular. Disturbed
places; Walker Co. (Nesom & Brown 1998); also far s TX; FL, LA, and TX. Spring–fall. Native of
Latin America. [Hapalanthus repens Jacq.] While some authorities indicate this species is native
to the U.S. (e.g., Kartesz 1999), we are following Wunderlin (1998) and Faden (2000b) in considering
it introduced. The species is reported to be self-compatible (Tucker 1989). It has been suggested
that the � bladeless petals and bushy stigmas are possibly adaptations to wind pollination
(Tucker 1989). I
COMMELINA L. WIDOW’S-TEARS, DAYFLOWER
Annuals or perennials; inflorescences enclosed in spathes; bract enclosing inflorescence
(spathe) folded, the two sides � parallel, conspicuously different in shape from stem leaves;
flowers bilaterally symmetrical; petals greatly or slightly unequal, blue or blue and white, the
upper 2 larger and clawed; stamens quite unequal, 3 fertile (1 of these different in size and form
from others), 3 slightly shorter and sterile (actually staminodia); filaments glabrous.
AA genus of ca. 170 species (Faden 2000b) of tropical and warm areas of the world. While
flowers of this family generally lack nectar (pollen is the only reward—Faden 1998, 2000b),
bees are reported to pierce the juicy lobes of the upper 3 sterile anthers of Commelina to obtain
“nectar” (Mabberley 1997). The common name DAYFLOWER comes from the extremely delicate
flowers which open in the morning but are gone by noon on sunny days (Kirkpatrick 1992).
(Named for the early Dutch botanists, Commelijn, on account of the 2 showy petals and 1 less
conspicuous petal. Linnaeus was referring to the three botanists of that name, two of whom,
Johannes, 1629–1692, and Caspar, 1667–1731 (nephew of Johannes), were conspicuous botanists,
while the third “… died before accomplishing anything in Botany”—Zimdahl 1989)
REFERENCES: Pennell 1916a, 1937, 1938; Brashier 1966; Faden 1989, 1993; Krings et al. 2002.
1. Leaf-like spathe enclosing flowers open on the top margin but with edges fused together along
the back margin; perennials with thickened roots.
2. Corolla with 2 uppermost petals blue and the lowermost (3rd petal) much smaller and white;
spathes often both scattered along the stem (located opposite the leaves) and near the stem
apex, usually 1 per node; leaf sheath margins inconspicuously ciliate with whitish hairs; leaves
with auricles at summits of sheaths; leaf blades 14–35 mm wide ___________________________ C. erecta
2. Corolla with all 3 petals blue, the lowermost slightly smaller; spathes usually in clusters near
the stem apex; leaf sheath margins conspicuously ciliate with reddish hairs; leaves without
auricles; leaf blades 20–65 mm wide ________________________________________________ C. virginica
1. Leaf-like spathe enclosing flowers open both on the top margin and also down the back margin
to where it attaches to its stalk; annuals with fibrous roots.
3. Corolla with 2 uppermost petals blue and the lowermost (3rd petal) much smaller and white
or paler than the others; leaf blades (10–)15–40 mm wide; leaf sheaths usually 10–20 mm
long; bottom edge of spathes (actually midvein) � straight; spathes usually pale with contrasting
dark green veins; capsules with 2 locules; seeds rugose pitted-reticulate __________ C. communis
3. All 3 petals blue, the 3rd only slightly smaller; leaf blades 7–15(–24) mm wide; leaf sheaths
usually 5–10 mm long; bottom edge of spathes usually curved (spathes falcate) OR � straight;
spathes without contrasting veins; capsules with 3 locules; seeds smooth to faintly alveolate
to reticulate.
4. Spathes usually distinctly falcate, the open margin usually ciliolate to glabrous; false anthers
of staminodes entirely yellow; upper cyme in larger spathes usually well-developed
and 1–several-flowered, exserted; capsules 4–6.3 mm long; seeds of ventral locule 2–2.8
(–3.2) mm long, deeply reticulate; only 2 of the 3 staminodes with well-developed false
anthers _____________________________________________________________________ C. diffusa