Cyperus.] CLII. CYPEEACE^. 1729' 



rays very unequal and sometimes the whole inflorescence contracted into a dense 

 sessile compound cluster or head of spikelets, the general rhachis of the inflore- 

 scence rarely shortly produced, showing an interval between each ray. Under 

 each ray is a persistent bract, one, two or more of the outer ones usually long 

 and leaf-like forming an involucre round the inflorescence, the inner bracts and 

 those which subtend the secondary rays and the spikelets usually small and 

 scale-like, those under the spikelets rarely entirely wanting. 



A very large and widely spread genus, second In the Order to Carex only in point of numbers, 

 but much more prevalent than that genus in the tropical and subtropical regions both of the 

 New and the Old World where it is everywhere abundant. It is represented also by a few 

 species in more temperate regions, but quite disappears in the extreme north and south as well 

 as on Alpine heights. 



The genus differs from those groups of Scirpus which having no hypogynous bristles formed 

 Brown's genus Isolepis, solely in the distichous arrangement of the glumes, and this character 

 is not constant in Cyperus pygmceiis, whilst in Scirpus cyperoides, a West Australian species, 

 the glumes are often very nearly distichous. From Schomus it is generally distinguished by the 

 habit and inflorescence', the flowers more numerous in the spikelets, the flowering glumes more 

 regularly distichous and the straighter rhachis of the spikelet, but none of these characters are 

 absolutely constant. A few exceptional intermediates occur among the species of both genera. 

 — Benth. 



Sect. I. Pycreus. — Spikelets flat with navimlar keeled glumes. Style vsvally 2-cleft.. 

 Nut more or less flattened, with one edge next the rhachis. 



Nut ovate or obovale, not exceeding half the length of the glume. . 



Dwarf tufted annual. Spikelets in loose clusters in an umbel of 3 to 6 

 rays. Keel of the glumes produced into a straight or recurved point, 

 the sides nerveless .... 1. C ptimilus. 



Perennial mostly under 1ft,. Spikelets 1 to IJ line broad, in a single 

 loose cluster or rarely 1 or 2 short umbel-rays. Glumes broad, obtuse, 

 the sides dark or with a dark patch 2. C. eragrostis. 



Annual or perennial much under 1ft. Spikelets 1 to IJ line broad, few 

 in the clusters in an umbel of few rays or all in one cluster. Glumes 

 broad, obtuse, very pale or yellowish green ..,.■.. ... 3. C, flaiescens. 



Perennial, mostly under 1ft. Spikelets narrow, in heads or clusters all 

 sessile or in an umbel of few rays. Glumes rather narrow, almost 

 acute, the sides of a pale brown . 4. C. glohosus. 



Perennial, 1 to 2ft. Spikelets 2 lines broad, the clusters in an umbel 

 of few rays. Glumes broad, rather acute, shining green or yellowish 5. C. imioloides. 

 Nut oblong, not exceeding halt the length of the glume. 



Spikelets narrow, very numerous, in a dense sessile compound cluster, 



rarely with 2 or 3 elongated umbel-rays 6. G. polystacliyns. 



Nut broad, almost as long as the glume. Tall perennial. 



Spikelets loosely spicate and distichous along the rays of a large com- 

 pound umbel 7. C. flavicomus. 



Sect. II. Juncellus. —iSpi/ceZcts flattened but usually thick. Siyle 2-cleft or rarely S-cleft. 

 Nut ovate or broad, with a flat or concave face next to the axis, the back convex or with a raised' 

 central angle. 



SpikeJets very numorous and closely packed in a small compound head 

 with an involucre of long leafy bracts. 



Dwarf annual. Involucre of several bracts. Pericarp not thickened . 8. C. pygmmis. 



Perennial, often 1ft. high. Involucre of 2 very long bracts. Pericarp 

 thickened at the base into a white prominent 2 or 3-lobed mass , . 9. C. cephalotes.. 

 Spikelets in clusters in a dense umbel of several short rays. Style hairy 10. G. platystylis. 

 Spikelets small numerous, in dense spikes along the rays of a large 



compound umbel. Stems 3 to 4ft 11. C. alopecuroides.. 



Sect. III. Eucyperus. — Spikelets Hat, the rhachis not winyed or rarely with anexcecdinglif 

 narrow border. Style 3-cleft. Nut equally triquetrous. 

 Spikelets numerous, in a 'single stnaill 'dense' globular head, with an 



involucre of long slender bracts 12. C. pulchelhu.. 



Spikelets spreading, pale-coloured, in a single sessile cluster or solitary. 

 Glumes obtuse or very shortly pointed. Nuts short. (G-raciles.) 

 Slender perennials. Spikelets or clusters terminal. 

 Glumes with 3 or i prominent nerves on each side and scarcely any 

 nerveless margins 13. C grac'.lis. 



