THE NOETH AMEBICAN SPECIES OF LASIACIS. 



By A. S. Hitchcock. 



INTBOBTJCTION. 



Lasiaeis is one of the few genera of grasses, excepting bamboos, 

 that have woody culms. It was long included in the allied genus 

 Panicum, from which it is well distinguished by the woody culms, 

 the general habit, and the technical characters of the spikelet, es- 

 pecially the shape of the fruit, the oblique position of the spikelets on 

 the pedicels, and the woolly tips to the glumes and lemmas, these tufts 

 of wool having suggested the generic name. Some of the species 

 creep on the floor of the forest and some form a tangled mass of branch- 

 ing culms, while the majority form strong central canes which clam- 

 ber up through shrubs or over the margins of woods for several 

 meters. 



The genus consists of 15 species, all confined to tropical America, 

 one species reaching subtropical Florida. 



DESCRIPTION OF THE GENUS AND SPECIES. 

 LASIACIS (Griseb.) Hitclic. 



Panicum section Lasiaeis Griseb. Fl. Brit. W. Ind. 551. 1864. Five species 

 are included in the section: P. divaricatum, P. sloanei, P. lanatum, P. com- 

 pactum, P. martinicense. Grisebach gives a satisfactory diagnosis of the sec- 

 tion. 



Lasiaeis Hitchc. Contr. U. S. Nat. Herb. 15: 16. 1910. The designated type is 

 Panicum divaricatum L. 



DESCRIPTION. 



Perennial, shrubby, often climbing grasses with much branched culms (her- 

 baceous and simple in L. procerrima) , fiat, often slightly petiolate blades, and 

 open or somewhat contracted panicles terminating the main culm and primary 

 branches, reduced panicles terminating the secondary, often fascicled branches. 

 Spikelets subglobose, ovoid, or ellipsoid, placed obliquely on their pedicels, the 

 glumes and sterile lemma broad, abruptly apiculate, papery-chartaceous, shin- 

 ing, often black at maturity, many-nerved, glabrous, or lauose at the apes 

 only. First glume rarely over one-third the length of the spikelet, somewhat 

 inflated-ventricose. Second glume and sterile lemma subequal, about as long 

 as the fertile lemma, or the glume slightly shorter, the lemma inclosing a mem- 

 branaceous palea and sometimes a staminate flower, rarely a second sterile 

 lemma present. Fertile lemma white, bony-indurate, obovoid, obtuse, the mar- 

 gins inrolled, inclosing the edges of the indurate palea, both lemma and palea 



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