139. GBAMINE^. 



iv hemispheric, coriaceous in fruit, never 



awned Genus 38, Isachne, 



B. Spikelets distinctly articulate on their pedicels and 

 falling from them or from the joints of an arti- 

 culate rhachis when mature. Glumes normally • 

 4, i and ii rarely sujipressed. Gls. iii and iv 

 both fioweriiii? or iii empty or paleate, often 

 male, iv always 2-sexual (exc. in Spinifex and 

 MaydecB, q.i\). Cp. p. 938 :— 



1. Rhachis of intlorescence inarticulate. Fig. gl. 



well developed, usually coriaceous or char- 



taceous in fruit. Gl". i and ii sometimes 



reduced :— 



«. Spkts. 1-tid. Gls. i and ii often reduced to a 



rim or 0. Stamens 6, mox'e rarely 3. Gen. 



33-35 ', . . 9. Oryzese. 



b. Spkts. 2-tld., upper fl. 2-sexual, lower male or 

 neuter, rarely both fertile or spkts. dioe- 

 cious. Gl. iii generally like ii in structure 

 and nervation; iv rarely finely awned 

 {Alloferupi<is spp.). Stamens 3-1 (genera 

 36-38 also included in Paw jce«) . . . Paniceae. 



i. Spikelets 2-sexual: — 



t Spkts. falling in groups or if singly then 

 subtended by an involucre of bristles 

 {Cenchatttra) .... Genus 39. Pennhetum. 

 \\ Spkts. falling singly and entire from the 

 rhachis or persistent pedicels, not 

 awned or if awned then similar and in 

 secund spikes and the awn from the 

 entire tip of gls. ii and iii {Evhino- 

 ehloa) or from the tips of i or ii 

 (Oplismenus) : — 

 t Gl. iv crustaceous in frt. Avith in- 

 rolled margins embracing the simi- 

 lar palea: palea of iii if developed 

 not attached to the fruit. Gen, 40- 



50 10. Panicastrae. 



XX Gl. IV with usually flat to hyaline 

 marf;ins, in fruit thinly cartila- 

 ginous, with the usually minute 

 palea of iii attached to its base. 

 Inflor. of digitate or subdigitate or 

 somewhat distant spikes. Gen. 



51-52 11. Digitariastrae. 



ii. Dioecious. Suffruticose. Male spkts. 2-fld. 

 articulate in rigid umbellate spikes. Fem. 

 in large globose heads of stellately spread- 

 ing quill-like rhachises, one spkt. at the 

 base of each Genus 53. Spinifex. 



2. Rhachis of spikes usually articulate and spkts. 



nonnally in pairs sessile and pedicelled, rarely 

 one of a pair suppressrcd (Diineria) or both 

 pedicelled, or spkts. in triplets (1 sess. and 

 2 pedicelled). Spikes simple or variously 

 arranged. Sessile spkts. (exc. sometimes the 

 basal) 2-sexual or female. Gls. i and ii firmer 

 than iii or iv, iv hyaline, often reduced to 

 the hj-aline base of an awn. (Ped. spkts. 

 usually fall from their pedicels. Sess. spkts. 

 fall with the collateral joint of the rhachis and 

 its companion pedicel. Rhachis I'arely tena- 

 cious or fused with pedicel) Andropogoneae. 



a. Joints and ped, not bulbous or adnate with 



one another, if thick then spikes digitate 



or in spathaceous panicles. Sess. spkts. 



940 



