Flora of the Hawaiian Islands
Monocotyledon Literature for Digitaria ciliaris
Wagner et al., 1990, 1999; Lorence & Wagner, 2019.
   Poaceae -- The Grass Family Bibliography
      Digitaria ciliaris

Common name(s): crabgrass, Henry's crabgrass, kukaepua`a
General Information
DistributionNative to China, Indochina, the Philippines, and Samoa.In the Hawaiian Islands, naturalized on Kure, Midway, French Frigate Shoals, Ni`ihau, Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Kaho`olawe, Hawai`i.

Annual; culms decumbent at base and geniculately ascending, 20‒100 cm long.
Leaves with sheath variously covered with bulbous based hairs, becoming glabrous apically; ligule 1‒3 mm long, truncate to rounded, erose; blade linear, 3‒25 cm long, 3‒10 mm wide.
Inflorescences composed of 2‒4(‒12) racemes, digitately or subdigitately arranged, central axis 0‒2.5 cm long (often short and contracted in Marquesan collections), racemes stiff, 2‒6(‒12) cm long, sometimes sparsely covered with long white hairs, axis trigonous, winged, margins scabrid-dentate. Spikelets in pairs, imbricate, narrowly elliptic, (2‒)2.5‒3.3(‒3.7) mm long, sometimes the pedicellate or both spikelets with stiff yellowish bristles, apex sharply acute; proximal glume triangular, usually 0.2‒0.4 mm long, second glume (½‒)⅔‒¾ as long as the spikelet, 3-veined; first lemma as long as the spikelet, 7-veined, the veins smooth and evenly spaced or with a wide interval flanking the midrib, appressed puberulent, silky pubescent or rarely short villous, usually ciliate, second lemma narrowly ovate, ca. 2.8 mm long, hyaline, 3-veined, glabrous; palea similar in shape and texture to lemma, ca. 2.8 mm long, 2-veined, clasped by the lemma.
Caryopsis gray to pale brown, ellipsoid.
2n = 18, 36, 54, 60, 68, 70, 72.
Compared with plants from many other regions (except the Hawaiian Islands), collections from the Marquesas Islands tend to be comparatively smaller and more compact with shorter, more contracted inflorescences.
Warren Wagner