149 



inflorescence (culms) or, in the perennial species, consist of culms and 

 short, leafy, usually biennial shoots {innovation shoots) which grow into 

 culms only in the second season ; innovation shoots either piercing 

 the subtending sheath at the base and growing up outside it, often as 

 runners or stolons (extravaginal), or inside the sheaths, which may or 

 may not be thrown aside {intravayinal); culms jointed, internodes 

 usually hollow, closed at the nodes, with or without an annular 

 swelling above the nodes and within the sheaths {culm nodes), all the 

 branches and their leaf-supported ramifications with a 2-keeled dorsal, 

 usually hyaline, leaflet at the base. Leaves alternate, usually 2-ranked, 

 ■ rarely pseudo-opposite owing to the alternation of long and " very short 

 internodes, very often crowded in tufts or fan-shaped bunches at the 

 base of the culms, or in some cases also of their upper branches, in the 

 perfect form (foliage leaves or "leaves" simply) consisting of sheath 

 ligule and blade, sheaths with the margins free {open sheaUis) or more 

 or less connate {closed sheaths), clasping each other or tlie culm, 

 finally often loosened or sometimes slipping from the culm and more or 

 less spreading, of the same structure throughout, or with an annular 

 succulent swelling at the base {sheath nodes), which becomes at 

 length hardened and persistent, or partly shrinks, leaving a depressed, 

 often dark coloured annidar mark ; ligules placed transversely at the 

 inside of the junction of the sheath and l^lade, consisting of a 

 membrane or of a fringe of hairs, rarely altogether absent; blades 

 usually long and narrow, entire, parallel-nerved, rarely ovate, cordate 

 or sagittate, usually more or less gradually passing into the sheath, 

 rarely articulated with it or constricted at base into a petiole, folded or 

 convolute in the bud, and often folding or rolling up in the mature 

 state as they become dry, usually much reduced or quite suppressed in 

 the lowest leaves which, in the perennial species act as bud scales, 

 sometimes also in the upi)er leaves. 



Inflorescence terminal, rarely terminal and lateral, built up of the 

 variously arranged spikelets, panicled, racemose, capitate, simply, or 

 compoundly spicate, very rarely consisting of a single spikelet, nearly 

 always ebracteate, Spikelets all alike or heteromorphous, diftering 

 in sex and (in correlation with the sex) more or less also in the general 

 structure, bisexual with all the flowers hermaphrodite, or with hermaph- 

 rodite and male, or female and male flowers in the same spikelet, or 

 unisexual (monoecious or dioecious). Mature spikelet falling entire 

 from the tips of the pedicels, or together with a part of the pedicel or 

 of the rhachis, or breaking up above the glumes into as many false 

 fi'uits as there are fruiting florets, rarely persistent and shedding the 

 grains. In the first case the glumes, in the second the valves are 

 often decurrent into a caUous sweUing or extension {callus) at the 

 insertion on the pedicel or rhachiUa respectively. 



About 325 genera, comprising 3,000 to 3,500 species in aU parts 

 of the world. 



The typical structure of the spikelets is sometimes more or less 

 obscured by the reduction or suppression, or by pecular modifications 

 of certain parts, generally in obvious correlation to the loss of functions, 



