The current study contributes to the knowledge of the Colombian grasses in collaboration with the Biodiversity Program and the Colombian Flora Inventories. Taxonomic position. The genus Eragrostis is placed in the tribe Eragrostisae, which in the New World includes three minor subtribes (Cotteneinae, Unolinae, and Eragrostidinae) that diverge as a clade at the base of the chloridoids (Peterson et al. 2007). The Eragrostidinae is characterized by hairy or glabrous culm nodes, hairy or glabrous rachillas, entire lemma apices that have parasols, mucronate or short awns (only in the last two genera), glabrous or scabby lemmas that have (1)3(5) )- nervous and short basal microhair cells (15−75 µm) on the abaxial epidermis of the leaf blade.
The most extensive experiment to date is lazarides'. 1997) treatment of the Australian Eragrostis, in which he recognized six groups based primarily on spikelet disarticulation. Ecology and geographic distribution.-The 25 species of Eragrostis in Colombia are widely distributed among the coast (mainly Caribbean coast), Andes, llanos, woodlands, cultivated fields, and urban sidewalks. The annual species are more conspicuous along the coastal sandy plains, the interior valleys on the western slopes and in the dry Andean valleys at lower altitudes.
Caryopsis morphology.-The caryopsis contains many morphological features that are important tools in the identification of species and this information can be used to derive hypothetical relationships between the grasses (Boechat & longhi-wagner 2003; colbry 1957; peterson et al. 2007 ; Terrell & Peterson 1993). The shape of the grain can vary from spherical to much longer as wide (ellipsoid, obovoid, ovoid, rectangular-prismatic, etc.). The embryo is located on the dorsal (abaxial) surface of the grain and the hilum is the small scar remaining from the attachment of the funiculus found near the base on the ventral surface.
The surface of the grain can be smooth to various sculptures and is often striated to form nets.
Caryopsis, lateral view
Spikelets mm, 3–10-flowered, striate-lanceolate, plumose to yellowish; disarticulation irregular to acropetal, proximal segments of rachis persistent; scales 1.2-3 mm long, subequal, lanceolate, hyaline; Caryopses 1-1.7 mm long, ellipsoid to oblong, strongly dorsally flattened, ventral surface with a shallow, wide groove or not grooved, smooth to striated, mostly translucent, elliptical in cross-section, light brown, bases often greenish. Panicles cm, terminal and axillary, ovate, open to slightly compressed; primary branches 0.1-0.5 cm long, compressed to strongly branched, glabrous; pulvini sparsely hairy or glabrous; petioles 0.2-1 mm long, ciliate.
Leaf sheaths overlapping, ½ to about as long as internodes below, sparsely pubescent at margins, apex pubescent, hairs up to 8 mm long, not papillose; ligules 0.2-0.4 mm long; leaflets cm long, 1-3 mm wide, straight or involute, abaxial surfaces glabrous, adaxial surfaces behind the ligules densely hairy, elsewhere usually glabrous, occasionally sparsely hairy. Leaf sheaths 1/2-2/3 as long as internodes above, ciliate at apex and along upper margins; ligules 0.2-0.3 mm long, ciliate; blades (5−)8−22 cm mm, involute, rarely flat, mostly glabrous above and below, scaly towards the top and along the edges, sometimes with hairs on the edges, hairs up to 7 mm long. Panicles cm, open, ovate, ascending primary branches 0.6-15 cm long, extending up to 100° from the bracts, branches pubescent, not flowering at the base; secondary branches composed of loosely overlapping spikelets; pulvini ciliate, hairs up to 7 mm long; peduncles 1.4-5(-7) mm long, erect, veined, spreading.
Leaf sheaths ¾ to about as long as internodes above, white cilia densely apically and along margins, sometimes with scattered hairs on abaxial surface; ligules 0.5−0.9 mm long, ciliate; blades 1.5−16.5 cm mm, flat to involute, glabrous and sometimes glabrous beneath and glabrous above. Pedicels cm, open, narrowly ovate to oblong, more or less densely flowered, primary branches 1.5-5 cm long, spreading, solitary at a node, flowered to the base, branches diverging 0 −70° from the rachis; pulvinia pilose, hairs up to 4 mm long; pedicels 0−1.5 mm long, shorter than the needles, appressed, with a few scattered hairs. Leaf sheaths overlapping down to ½ length of internodes above, slightly crowded at apex and along margins below, hairs up to 3 mm long and papillose base; ligules 0.1−0.3 mm long; blades 3−8(−10) cm long, 2−4 mm wide, flat, slightly crowded with papillose-based hairs.
Panicles 4-13 cm long, cm wide, narrow, ovate, open, slightly appressed; primary branches 2-7 cm long, ascending, rigid, extending up to 90º from wounds; secondary branches widely spreading; pulvina glabrous, smooth; pedicels 0.5-2.5 mm long, shorter than spikelets. Leaf sheaths 1/3-2/3 as long as internodes, sparsely pubescent at apex and along upper margins, hairs up to 2.5 mm long, sometimes margins glabrous; ligules 0.4-0.6 mm long, ciliate; blades 6.5–10 cm × 2–5 mm, flat, occasionally loosely coiled near apex, glabrous. Leaf sheaths overlapping below, 3/4 as long as internodes above, ciliate at apex and along upper margins; ligules 0.2-0.5 mm long, ciliate; blades 5−40(−45) cm.
Leaf sheaths overlapping below, ½-3/4 as long as internodes above, pubescent at tips, hairs up to 4 mm long; ligules 0.2-0.5 mm long; blades 2–20 cm × 1–4.5 mm, straight to involute, abaxial surface glabrous and smooth, adaxial surface wrinkled. 0.1–0.2 mm long; leaflets 25–50 cm long, 1.5–6 mm wide, flat to involute, glabrous abaxially, curled adaxially, sometimes with a few scattered hairs at the base. Leaf blades overlapping below, half as long as internodes above, mostly glabrous, hairy at tips, pubescent to 4 mm; ligules 0.2-0.3 mm long; leaflets cm long, 1-5 mm wide, involute, abaxially glabrous, adaxially scabridular, sometimes sparsely hairy.
Leaf sheaths 1/2 as long as internodes, ciliate at apex, collar and along margins of upper part, hairs up to 4 mm long, stiff; ligules 0.2−0.3 mm long, ciliate;. Panicles cm, open, narrowly ovate, primary branches 0.5−4 cm long, sometimes with irregular glandular areas below branch bases, branches diverging 20−100° from rachises; pulvinia ciliate or glabrous; pedicels 0.8−4(−7) mm long, mostly pendulous, pendulous to erect. Leaf sheaths 1/2 length of internodes to imbricate, vicid, ciliate at apex, collar and along margins of upper part, hairs up to 4 mm long, stiff; ligules 0.2−0.5 mm long; blades 4−15 cm long, 2−4 mm wide,.
Panicle 6−22 cm long, 2−9 cm wide, open, cylindrical to ovate-lanceolate; ascending branches 0.5-6.5 cm long, spreading 20-90º from rachises, viscous; pulvini in the axes of the primary branches sparsely ciliate or glabrous; pedicels 0.5−5 mm long, erect.
