A flora of Manila - Rainforestation

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4. Rachis glabrous.
A FLORA OF MANILA
5. Leaves very short, less than 5 cm long; spikelets crowded.
8. C. vialacccnsis
5. Leaves long, sometimes equaling the stem; spikelets laxly
disposed 9. C. distans
2. Rachilla of spikelets distinctly winged.
3. Slender plants less than 0.5 m high.
4. Spikes mostly dense, of from 3 to 8 spikelets; roots with thickened,
ovoid or globose tubers 10. C. rotundus
4. Spikes lax, of from 2 to 6 spikelets; glumes rather distant.
11. C. zollingeri
3. Coarse plants often 1 m high; spikes 3 to 6 at the end of each
branch of the inflorescence, densely many-flowered.
12. C. radiatus
1. C. difformis L.
A tufted glabrous annual 10 to 40 cm long, the stems sharply 3-angled ar
the top. Leaves rather flaccid, somewhat shorter than the stems, 2 to 3
mm wide. Inflorescence umbellate, simple or compound, subtended by two
leaf-like bracts, contracted or spreading, the rays 1 to 5 cm long, some
sessile, some long-peduncled. Spikelets very numerous, 2 to 5 mm long,
crowded in globose or ovoid masses on the ends of the branches, each
spikelet with from 8 to 25 flowers, the flowering glumes about 0.6 mm
long, obtuse, brownish. Nutlets about 0.6 mm long.
In open wet grass lands, fl. all the year; throughout the Philippines. A
characteristic rice-paddy weed throughout the warmer parts of the Old
World, introduced in Mexico.
2. C. haspan L.
A tufted, glabrous, rather flaccid plant 10 to 40 cm high. Leaves often
as long as the stem, sometimes shorter, or nearly wanting, 3 to 5 mm wide.
Inflorescence umbellate, simple or compound, of few or many crowded or
spreading rays, each with few to many spikelets, dense or lax. Spikelets
brown, 3 to 10 mm long, 8- to 25-flowered, the glumes about 1.2 mm long,
imbricate, obtuse. Nutlets 3-angled, about 0.4 mm long.
In open, wet, grass lands, especially rice-paddies, fl. all the year; through-
out the Philippines. All warm countries; a characteristic rice-paddy wf-ed.
*3. C. FLABELLIFORJIIS Rottb. Umbrella Plant.
A stout, erect, tufted plant reaching a height of 1.5 m, the stems up to
1 cm in diameter, base covered with leafless sheaths. Leaves all crowded
in a dense, spirally arranged whorl at the ends of the stems, spreading, numerous,
up to 30 cm long, 0.5 to 2 cm wide, acuminate. Umbels in the
leaf-axils, numerous, 8 cm wide or less, their peduncles slender, 10 cm long
or less. Spikelets sessile, in peduncled and sessile heads, oblong, up to 1
cm long, the glumes 20 to 30, about 2 mm long. Nuts 0.8 mm long.
Frequently cultivated, but not spontaneous, fl. Dec-March. A native of
Arabia and Abyssinia, now cultivated in many warm countries.
4. C. diffusus Vahl.
An erect glabrous perennial 30 to 60 cm high, the leaves basal, flat,
broad, numerous, crowded, equaling or longer than the stems, 3-nerved, 8
to 15 mm wide, the root-stock short. Stems 3-angled, the bracts subtending
the inflorescence leaf-like, 10 to 50 cm long, broad, spreading. Umbels
8 to 20 cm in diameter, decompound, rather lax. Spikelets 3 or more