GKAMINEiE. 553 



126, P. dichotomum, L. Leaves lanceolate, acuminate ; panicle few-branched : 

 branches scattered, simple, or lower compound : pedicels unequal, hair-like : spikelets ellip- 

 tical, bluntish ; lowest glume J-i as long as the spikelet, bluntly deltoid, 2 superior equal- 

 ling the flower, 9-1-nerved, third with a short palea ; fertile flower ellipsoidal, blunt, 

 smooth, more than half terete: palea slightly convex. — Leaves 2"'-li"' broad : ligule long- 

 ciliate ; panicle 1"-1£", spikelets J 7 " long. The West Indian forms are : 



a. acuminatum, Sw. / Leaves and sheaths densely and softly pilose ; panicle subincludcd ; 

 spikelets pubescent. — Stem creeping, cr ascending, 6"-8" long. 



$. giabrescens. Densely csespitose, low ; leaves glabrous, except at the tuberclcd-ciliate 

 base: sheath ciliate ; panicle peduncled, exserted ; spikelets glabrous. 



Hab. Jamaica, Sw., M'Nb., in sandy hills (a) ; Pd., in mountain-savannahs (0) ; [United 

 States !]. 



38. ISACHNE, R. Br. 



Character of Panicum, but sterile flower chartaceous like the fertile one. — Habit of Pani- 

 cum, sect. Miliaria. 



127- I. arundinacea, Gr. Stout, glabrous ; leaves long, lanceolate, narrowly acuminate ; 

 panicle dense, oval •. branches compound, filiform : pedicels short, unequal -. spikelets ovoid ; 

 2 inferior glumes equal, costate-5-nerved, glabrous, lowest often ciliate above, exceeded by 

 the £ flower, as long as the fertile ; both flowers glabrous, half-terete. — Panicum, Sw. ! P. 

 dispermum, Lam. I. panicea, Tr. I. dubia, Kth. — 4-10' high, woody at the base; leaves 

 5"'-10"' broad ; panicle 3"-6", spikelets i'" long.— Hab. Jamaica !, Sw., Macf, in high 

 mountains, S. Andrews; S. Vincent, Guild.; [Martinique!, Mexico!, Venezuela!]. 



128. I. rigens, Trin. Decumbent, branched ; leaves short, linear, acuminate, usually 

 scabrous : sheath ciliate ; panicle short, spreading : branches scattered, nearly simple : pedi- 

 cels unequal, obtuse-angled; spikelets ovoid; 2 inferior glumes unequal, 7(-5)-nerved, 

 slightly scabrous, lowest exceeded by the $ flower, as long as the fertile ; both flowers gla- 

 brous, pubescent at their callus, fertile and little distant, half-terete. — Panicum, Sw. ! P. 

 arbusculum, Sieb. Mart. 265. — 6"-12" long; leaves l"-2" long, \\"-2" broad; panicle 

 l"-2", spikelets yiong. — Hab. Jamaica!, Sw., Macf, in high mountains; [Martinique! ; 

 Venezuela !]. 



129. I. pygmsea, Gr. («. sp.) Low, decumbent, cscspitose, diffuse, glabrous; leaves 

 short, linear, acuminate, rigidly spreading, polished-striate, cartilaginous at the margin : 

 sheath shortly ciliate above, or glabrescent ; panicle short, simple, contracted : pedicels 

 short, angular : spikelets ovoid ; 2 inferior glumes subequal, 5-nerved, glabrous, exceeded , 

 by both flowers ; both flowers glabrous, half -terete. — About 2" high, forming tufts of ' 

 3"-4" diam. from a fascicled root; leaves distichous, 6'" long, i 1 "— V" broad; panicle 

 scarcely exserted, linear, 3"'-6'" long, green : branches few, appressed, with a few, geminate, 

 unequal pedicels ; spikelets blunt, \ m long. — Hab. Jamaica !, Macf., probably an alpine 

 grass, like the preceding. 



39. HYMENACHNE, P. B. 



Character of Panicum, but fertile flower chartaceous, or coriaceous, not indurated in fruit, 

 and panicle contracted. — Tall, erect, glabrous, aquatic or bog-grasses ; panicle long, spiciform. 



130. H. Mynras, P. B. Leaves cordate at the clasping base, lanceolate-acuminate, or 

 lanceolate-linear ; panicle cylindrical : pedicels short : spikelets lanceolate, acuminate ; 

 lowest glume one-third as long as the spikelet, 2 superior 3-5-nerved, slightly unequal, third 

 devoid of a palea ; fertile flowers chartaceous, oblong-lanceolate, pointed, little shorter than 

 the third glume, compressed from the back. — Trin. Ic. t. 205. — Panicum, Lam. P. amplexi- 

 caule, Rudg.—& high; leaves, 6"'-2'" broad ; panicle green, 6"-15", spikelets 2'" long — 

 Hab. Jamaica !, Pd., Dist., in ditches; Dominica!, Jmr. ! Trinidad !, Cr*; [French islands 

 to Brazil ! ; East Indies !]. 



131. H. fluviatilis, Ns. Leaves linear ; panicle cylindrical : pedicels short : spikelets 

 ovate, pointed ; lowest glume half as long as the spikelet, 2 superior 7-9-nerved, equal, third 

 with a palea ; fertile flowers coriaceous, ellipsoidal, pointed, subterete, half as long as the 

 second and third glume.— Trin. Ic. t. 204.— P. vilfoides, Trin.— H'-3' high ; leaves 2"'-3'" 



