Grasses of Porto Rico 379 



14. DIMORPHOSTACHVS Fourn. Comptes-Rendus Acad. 



Par. 80 : 441. 1.S75 



I. DlMORPHOSTACHVS PEDUNCULATA (Poir.) Fouill. McX. PI. 2: 



15. 1886. 



Paspahun pcdnnculatuin Poir. in Lam. Encycl. Suppl. 4: 315. 

 1816. 



AdJLintas road, near Ponce, Heller 6354. 



15. PANICUM L. Sp. PI. 55. 1753 



I. Apex of the panicle- branches not extending beyond the insertion of the spikelets. 

 a. Stems herbaceous. 



Spikelets scattered, on long pedicels of varying length. 

 I Fourth scale of the spikelet smooth : low grasses, less than 5 dm. tall. 



Panicle large and eftuse, over i dm. long : spikelets numerous, less 

 than 1.5 mm. long. 

 Leaf-blades narrowly ovate, rarely exceeding 7 cm. long : 



spikelets I mm. long. I. P. hrevifolium. 



Leaf-blades lanceolate, rarely less than I dm. long : spikelets 

 1.3 mm. long. 2. P. trichanthttm. 



Panicle small, less than I dm. long : spikelets few, 1.5 mm. long or 

 more. 

 Stems erect, if prostrate in age never rooting at the lower nodes. 

 Spikelets less than 2 mm. long. 



Leaf-blades with the upper surface hirsute, the larger 



over I cm. wide. 3. P. comophylhim. 



Leaf-b'ades with the upper surface glabrous or merely 

 puberulent, less than 5 mm. wide. 



4. P. A'ashianutn. 

 Spikelets more than 2 mm. long. 5. P. consangiiineum. 

 Stems erect only toward the end, the base prostrate and rooting 

 at the lower nodes. 

 Leaf-blades lanceolate, pubescent, less than 5 mm. wide. 



6. P. pai-vi/o/im/i. 

 Leaf-blades ovate-lanceolate, more than 5 mm. wide. 



7. P. oplismenoides. 

 Fourth scale of the spikelet transversely rugose : tall stout grasses. 



8. P. tnaxi»iuni. 

 Spikelets crowded on short nearly equal pedicels, in short clusters on one side 



of the panicle-branches. 

 Outer scales of the spikelet with cross-veinlets connecting the longitu- 

 dinal nerves. 9. P. paniculattim. 

 Outer scales without cross-veinlets. 



Fourth scale of the spikelet transversely rugose. 



Spikelets about 2 mm. long : stems slender : leaf-blades ovate- 

 lanceolate, usually less than 5 cm. long. 



10. P. prostratttm. 



