FEB. 1903. PLANTVE YUCATAN^ MILLSPAUGH & CHASE. 



41 , 



Cenchrus brevisetus Fourn. ibid. 



Spikes exserted, 2.5-5 cm - l n g f 10-20 involucres, 8x9 mm., 

 including bristles, on pubescent pedicels, the 8-9 divisions spine- 

 pointed, erect, long-ciliate to near 

 the apex; spines 24 mm., pur- 

 plish, pubescent, ciliate at the 

 base, retrorsely barbed toward 

 the apex; basal bristles numer- 

 ous, stout, scabrous. Spikelets 

 3-4 in each involucre, 2x6 mm., 

 sometimes purplish above, 

 lanceolate -ovate, acuminate. 

 First glume minute, faintly 3- 

 nerved, hyaline ; second "fa the 

 length of spikelet, broadly 

 ovate, acute, 5-nerved, middle 

 internerves puberulent, third as 

 long as the floral glumes or 

 nearly so, acute, 5-nerved, sub- 

 tending a scabrous 2-nerved 

 palea of its own length ; fruiting 

 glumes, 1.9x6 mm., lanceolate- 

 ovate, acuminate, the glume 

 5-nerved, basal keels winged; palea puberulent above between the 

 2 nerves. Grain stramineous, obovoid-oblong, 1.8x2.7 mm.; in sec- 

 tion convexo-concave. 



Hab. Sands of the beach at Progreso, especially near the cattle 

 pens where many cattle are herded on arrival from Tampico and 

 other ports on the Gulf coast of Mexico, Jan. 26, 1895, Millspaugh y 

 Armour Exped. 205. 



Cenchrus echinatus L. Sp. PI. 1050. 



Spikes short-exserted, 3-8 cm. long, of 10-25 involucres, 8 x 13mm., 

 including bristles, on densely 

 hirsute pedicels, the 8-10 divis- 

 ions spine-pointed, erect; 

 spines 3-5 mm. long, purplish, 

 pubescent, long-ciliate at the 

 base, retrorsely barbed toward 

 the apex; basal bristles numer- 

 ous, slender, barbulate. Spike- 

 lets 4-5 in each involucre, i . 75 x 

 5.7 mm., lanceolate-ovate, acu- 

 minate. First glume */3 the 

 length of spikelet, lanceolate, 

 acute, 3-nerved, hyaline; sec- 

 ond, 2 /z the length of spikelet, 

 broadly ovate, truncate, 2-3 

 toothed by the excurrent tips 

 of the nerves, 5-nerved, mid- 

 dle pair of internerves puberu- 

 lent ; third nearly as long as floral glume, acute, 5-nerved, middle 



