STANDLEY TREES AND SHRUBS OF MEXICO. 67 



Culms not high-climbing, decumbent and rooting at base, forming a tangled 

 mass, with no strong central cane ; spikelets clustered toward the ends 



of the branches 4. L. rhizophora. 



Culms high-climbing, forming a strong central cane ; spikelets not clustered 

 toward the ends of the branches. 

 Blades glabrous on both surfaces, often more or less scabrous (see L. 

 ruscifolia, rarely with glabrous ovate-lanceolate blades). 

 Panicle few-flowered, 5 to 10 cm. long ; branches strongly zigzag, the 

 branchlets strongly divaricate or reflexed ; blades narrowly lanceo- 

 late, firm, mostly less than 1 cm. wide (sometimes wider on vigor- 

 ous shoots) 5. L. divaricata. 



Panicle many-flowered, usually 15 to 25 cm. long or more on the 

 primary branches ; branches straight or arcuate, not zigzag ; 

 blades mostly over 1.5 cm, wide. 



Spikelets globose, about 3 mm. long 6. L. globosa. 



Spikelets lanceolate-ellipsoidal, 3.5 to 5 mm. long 7. L. sloanei. 



Blades pubescent on one or both surfaces (sometimes glabrous in L. 

 ruscifolia). 

 Blades narrowly lanceolate, averaging 8 to 10 times as long as wide; 

 panicle large and open ; spikelets 4 to 5 mm. long. 



8. L. sorghoidea. 



Blades ovate-lanceolate or elliptic, sometimes lanceolate, often more or 



less cordate-clasping; panicle often compact or at least the 



branches commonly compactly flowered ; spikelets 3 to 4 mm. long. 



9. I/, ruscifolia. 



1. Lasiacis rugelii (Griseb.) Hitchc. Bot. Gaz. 51: 302. 1911. 

 Panicum rugelii Griseb. Cat. PI. Cub. 233. 1866. 



Rich woods, San Luis PotosI and Yucatan. Cuba (the type locality). 



Prostrate, the main canes slender ; branches commonly fascicled, very leafy, 

 the pubescent sheaths overlapping, the small, lanceolate, firm, puberulent, 

 somewhat cinereous blades oblique at base ; panicles short-exserted, few- 

 flowered. 



2. Lasiacis grisebachii * (Nash) Hitchc. Bot. Gaz. 51: 302. 1911. 

 Panicum, grisebachii Nash, Bull. Torrey Club 35: 301. 1908. 



Rich woods and shady banks, carpeting the floor of dark thickets, Veracruz. 

 Honduras; Cuba (type locality). 



Stems more slender, freely producing rootlets, the long narrow blades not 

 crowded; panicle branches ascending. 



3. Lasiacis oaxacensis (Steud.) Hitchc. Proc. Biol. Soc. Washington 24: 145. 



1911. 



Paniciim oaxacense Steud. Syn. PL Glum. 1: 73. 1854. 



Edges of woods, Veracruz, Michoacan, and Oaxaca (type locality). Guate- 

 mala and Jamaica to South America. 



Slender, straggling, decumbent and geniculate at base, with numerous aerial 

 rootlets, the long branches ascending and arcuate, with narrow scabrous blades 

 commonly 20 cm. long, and large open few-flowered panicles, the spikelets borne 

 at the ends of the branchlets. 



^Heinrich Rudolph August Grisebach (1814-1879), a native of Hanover, pub- 

 lished fn 1864 a " Flora of the Briti-sh West Indies," one of the most important 

 works upon the plants of tropical North America. He is known, too, for his 

 " Vegetation der Erde," published in 1872, a classic work upon plant geography, 

 and for numerous other botanical publications. 



