386 ENDOGENOUS PLANTS 



long, and 2 to 4 inches wide, pubescent above, smooth beneath ; slieaths smooth, 

 pubescent along the margins ; ligule short. 

 Hub. Fields. Nat. of Southern America. Ft. July. Fr. Sept. 



Obs. Long culture has produced several varieties of this noble 

 Grass, with grains of differant form and color. There is also a 

 remarkable vanity fre^nt, I believe, in the South west in which 

 a kind of hu^k, or involucre, is developed around every grain, or 

 sp'kelet, on the receptac'e. The Goethean theory of the modification 

 of leaves, at the successive stages of the vegetable progress, from 

 cotyledons to flowers, is well illustrated by the envelope, or " husk," 

 of an Etr of Indian Corn. Few heedless observers would be apt to 

 recognize the fact, that the several portions of that envelope are 

 the sheaths of abortive leaves : and yet nothing is more obvious, when 

 we examine them by the light of that theory. The spike of pistil- 

 late flowers is supported on a short axillary branch, with numerous 

 nodes, and very short internodes. As nodes are the points at which 

 leaves originate, we accordingly find a leaf or rather the sheathing 

 petiole of an imperfect one^-at each node of this short flowering- 

 branch ; and as the nodes are very close together, the sheaths 

 necessarily over-lap one another, and thus furnish a manifold 

 wrapper to the spike of flowers and fruit (i. e. the "Ear"). That 

 these several layers of the envelope are the sheathing portions of 

 abortive leaves, is demonstrated by the laminae, more or less de- 

 veloped, at their summits, and which, indeed, are sometimes seen 

 expanded to nearly half the size of an ordinary full-grown blade. 

 The sam3 doctrine applies to the chaff, or floral coverings, of all the 

 Grasses;* as it does, in fact, to those of all the flowering tribes. 



507. TRIP'SACUHI, //. 



[Gr. tribo, to rub ; perhaps in reference to the polished fertile spike.] 

 Rpikelets sessile, in terminal and subterininaiyomtee? spikes, which 

 spikes are solitary, or often digitate in twos or threes, the staminate 

 part above. STAMINATE SPIKELETS in pairs on each triangular joint, 

 longer than the joint, collateral, 2-flowered, the florets each witli 

 Zpaleae, and 3 stamens; anthers orange-colored, opening by 2 pores 

 at summit. PISTILLATE SPIKELETS single, 2-flowered (the lower one 

 neutral), deeply imbedded in each oblong joint of the cartilaginous 

 thickened rachis, and occupying a boat-shaped cavity which is 

 closed by the polished cartilaginous ovate outer glume ; inner glume 

 much thinner, boat-shaped. Paleae very thin, hyaline, and closely 

 packed together. Stifle long; stigmas very long, plumose, dark 

 purple. Grain ovoid, free. Perennial: culms cespitose, tall, branch- 

 ing, hard and smooth, solid with pith ; leaves very long, sublinear, 

 acuminate ; spikes separating at the articulations spontaneously, at 

 maturity. 



1. T. dactyloldes, L. Spikes usually 2 together, with the 

 contiguous sides flat, the upp3r half staminate. 

 FINGER-LUCK TRIPSACUJI. Gama Grass. Sesame Grass. 



Culms 3 to 6 feet high, the internodes broadly channelled on alternate sides ; 



* " Perigonia gramiuum sunt vaginae foliorum superstites,'' LISK. 



