GRAMINE.E. (GRASS FAMILY.) 579 



waste grounds, Florida to North Carolina. July - Sept. ® — Culms l°-2° 

 long. Involucre purplish. 



2. C. tribuloides, L. Involucres whitish, 10- 15 in a spike, -wedge-shaped 

 at the base, armed above with stout compressed broadly subulate erect or spread- 

 ing spines; bristles none; spikelcts mostly by pairs. — Sands along the coast. 

 Florida, and northward. July - Oct. ® — Culms prostrate, 1° - 2° long. Leaves 

 linear. Spikes 1' -2' long. 



52. STENOTAPHRUM, Trim 



A creeping and branching grass, with the awnless spikclets sunk in excavations 

 of the continuous flattened rachis. Spikclets by pairs, one pedicelled and imper- 

 fect, the other sessile, and with the structure of Panicum. 



1. S. Americanum, Schrank. (Rottboellia dimidiata, Ell) — Damp 

 sandy places along the coast, Florida to South Carolina. June- Sept. ]\. — 

 Smooth throughout. Culms flattened, creeping, the branches nearly opposite ; 

 flowering culms erect, 6'- 12' high. Leaves 2' -6' long, linear, obtuse, flat or 

 folded, contracted at the base. Spikes lateral and terminal, peduncled, 2' -5' 

 long. Sterile spikelet neutral or rudimentary. Fertile spikelet sessile; the up- 

 per glume 7-nerved, 3 times the length of the lower one. Palea of the sterile 

 flower coriaceous, like those of the perfect one. 



53. ROTTBCELLIA, Brown. 



Erect perennial mostly tall grasses, with flat or channelled leaves and spiked 

 inflorescence. Spikes nearly terete, jointed. Spikelets awnless, borne by pairs at 

 the base of each joint ; one imperfect, on a coriaceous and closely appressed ped- 

 icel ; the other sessile, embedded in an excavation of the joint, 2-flowered. Glumes 

 2, the exterior one flat, coriaceous, with a hinge-like depression at the base, the 

 interior boat-shaped, membranaceous. Palea? hyaline, 1 -2 in the staminate or 

 neutral lower flower, and 2 in the upper and perfect flower. Stamens 3. Styles 

 2. Grain compressed, free. — Spikes solitary on lateral and terminal peduncles 

 or branches. 



1. R. rugosa, Nutt. Culms compressed ; peduncles or branches clustered, 

 short, included in the sheaths of the elongated upper leaves ; spikes spreading, 

 slightly compressed; sessile spikelet shorter than the joint; lower glume lance- 

 olate, transversely rugose ; sterile flower neutral. — Pine-barren swamps and 

 ponds, Florida to North Carolina. Sept. — Culms 2° -4° high. Spikes green, 

 l£'-2' long, I" in diameter. 



2 R. corrugata, Baldw. ? Culm stout, compressed; peduncles mostly 

 single, elongated, spikes slightly compressed, erect ; spikelets longer than the 

 joint; lower giumc longitudinally grooved and somewhat reticulated, ovate; 

 sterile flower staminate. — Low pine barrens, Georgia and Florida, near the 

 coast Sept. and Oct. — Culm 2°-4° high. Spikes 4'-6' long, 2" in diam- 

 eter, purplish. 



3. R. cylindrica. Culm slender, terete; leaves narrowly linear j peduncles 

 single, elongated ; spikes slender, terete, mostly curved ; spikelets as long as 



