51. Paspalum L. Paspalum 



Mostly perennials; ligule a scale; inflorescence a panicle of 1 to several racemes 

 on the common axis; raceme with a more or less flattened rachis; the numerous 

 spikelets borne in pairs or singly in 2 rows on the abaxial side of the rachis, the 

 pedicels of the pairs short and unequal in length; zone of abscission at the base of 

 the spikelet at the end of the pedicel; spikelets each with a single perfect floret 

 subtended by 2 or 3 scales, when 3 then the lowest one being a minute abaxial 

 first glume; next highest one of the adaxial second glume as large or nearly as 

 large as the spikelet; the abaxial sterile lemma representing the sole remains of a 

 neutral lower floret; fertile lemma adaxial, chartaceous-indurate, convex, the 

 margins revolute, clasping the fertile palea of similar texture, the fertile lemma 

 and palea and their enclosures and appendages constituting the "fruit." 



A genus of about 250 species in warm regions. Most Paspalums are of great 

 economic importance as forage plants. 



I. Racemes 20 to 50 per panicle, eventually deciduous from the panicle axis; 



commonly attached and floating aquatics; spikelets solitary, 1.2-1.7 

 mm. long, pubescent 16. P. fluitans. 



1. Racemes fewer, persistent (2) 



2(1). "Second" (only) glume and sterile lemma abruptly pointed beyond the 

 blunt fruit (3) 



2. Second (only) glume and sterile lemma not abruptly pointed beyond the 



fruit (5) 



3(2). Spikelets solitary (that is, not paired) and glabrous; fruit with microscopic 

 cilia apically 14. P. acuminatum. 



3. Spikelets paired and silky-fringed (4) 



4(3). Racemes (8 to) 12 to 22 per panicle; spikelets 2-3 mm. long 



5. P. Urvillei. 



4. Racemes 3 to 6 (to 11) per panicle; spikelets 2.8-4.1 mm. long 



6. P. dilatatum. 



5(2). Spikelets 3.6-5 mm. long (6) 



5. Spikelets less than 3.6 mm long (8) 



6(5). Spikelets solitary 13. P. vaginatum. 



6. Spikelets paired; fruit brown (7) 



7(6). Spikelet pairs remote, usually not overlapping; first glume present on at 



least some of the spikelets; rachis of raceme 0.5-0.8 mm. broad 



1. P. bifidum. 



7. Spikelet pairs approximate, overlapping; first glume absent; rachis 1-1.5 mm. 



broad 2. P. floridanum. 



8(5) . All the spikelets solitary, never paired (9) 



8. Some and usually nearly aU the spikelets paired (12) 



9(8). Spikelets 1.4-2.3 mm. long 15. P. dissectum. 



9. Spikelets 2.4-3.6 mm. long (10) 



10(9). Panicle axis 3-10 (-19) cm. long; racemes 2 to 9 per panicle 



7. P. laeve. 



10. Panicle axis obsolete or only to 2.5 cm. long; racemes 1 to 3 per panicle (11) 



11(10). Spikelets 2.5-3.2 mm. long; second glume minutely pubescent; first 

 glume usually present 12. P. distichum. 



II. Spikelets 3.1-4.5 mm. long; second glume nearly glabrous; first glume usually 



absent 13. P. vaginatum. 



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