90 A. FLORA OF MANILA 



3. Empty glumes usually muricate, the 'second and third cuspidate or 

 awned. i 



4, Lower spikes as long as or shorter than the internodes; third 

 glume awnless or nearly so ; spikelets 2.5 to 3 mm long. 



4. P. eolonum 

 4. Lower spikes much longer than the internodes; coarse erect 

 grasses, the spikelets usually long-awned. 

 5. Spikelets nearly 5 mm long, green or purplish; an aquatic 



grass 5. P. atagninum 



5. Spikelets 3.5 to 4 mm long, usually purplish 6. P. crusgalli 



2. Spikelets crowded in spiciform or narrow, cylindric panicles, or pedi- 

 cellate on the spreading, racemosely arranged panicle-branches. 



8. Branches elongated, ascending or spreading 7. P. auritum 



3. Panicles dense, cylindric. 



4. Spikelets about 5 mm long, acuminate; a coarse, perennial, 



aquatic grass 8. P. amplexicaule 



4. Spikelets about 2.5 mm long; a slender, erect annual grass. 



» 9. P. indicum 

 2. Spikelets in open, diffuse panicles. 



3. First glume as long as the spikelet or nearly so; spikelets promi- 

 nently acuminate ^ 10. P. caudiglume 



3. First glume much shorter than the spikelet. 



4. Second glume decidedly shorter than the flowering glume; panicles 



simple 11. P. nodosum 



4. Second glume equaling or longer than the flowering glume; pani- 

 cles decompound. 



5. Annual 12. P. psilopodium 



5. Perennial. 



6. Tall, leafy, 2 to 3 m high; cultivated 13. P. maximum 



6. Less than 2 m high. 



7. Panicle branches rather stiff, spreading; spikelets 3.5 to 4 



mm long, aquatic or subaquatic 14. P. paludosum 



7. Panicle branches somewhat nodding; spikelets 3 mm long. 



15. P. repens 

 1. Spikelets laterally compressed; small, slender, more or less prostrate, 

 spreading grasses. 



2. Panicles very lax, open, the spikelets scattered 16. P. warburgii 



2. Spikelets densely crowded on the usually ascending branches. 



17. P. 



1. P. FLAVIDUM Retz. 

 A • loosely tufted, erect, somewhat branched, rather coarse grass 0.5 



to 1 m high, the stems somewhat compressed. Leaves linear-lanceolate, 

 smooth, glabrous, acute or acuminate, 8 to 15 cm long, 5 to 10 mm wide, 

 the lower sheaths usually loose. Inflorescence elongated, of erect, stout, 

 scattered, racemosely arranged spikes sh&rter than the internodes, the 

 spikes 1 to 2.5 cm long, about 5 mm wide. Spikelets very pale, densely 

 arranged in 2 rows, divaricate, about 3 mm long. 



Very common in open waSte places, roadsides, etc., fl. all the year; 

 throughout the Philippines at low altitudes, certainly introduced. Trop- 

 ical Asia and Africa, Malaya. 



2. P. punctatum Burm. 



A stout, erect, perennial grass 1 to 1.5 m high, the base usually floating 



