438 Key to the System of 



PHILHYDREAE. 



1867. Sepals much longer than the petals. 



Leaves narrow-ensate, passing gradually into their much 

 compressed stalks, the uppermost shortened into bracts ; 

 spike occasionally branched ; flowers comparatively large, 

 bending their bract downward ; spike somewhat inter- 

 rupted ; bracts exceeding the flowers, much pointed ; 

 sepals and petals yellow ; fruit ellipsoid ; placeiitaries fixed 

 to the walls of the fruit-cells ; seeds numerous, minute, 

 ovate-ellipsoid. P. lanuginosum. 



XYRIDEAE. 



XYRIS. 



1868. Paired sepals hardly keeled. 



Rather tall, quite slender ; leaves often somewhat twisted, 

 narrow - linear ; flower - headlets rather small, usually 

 ellipsoid-ovate ; bracts scarcely seriated, dark, but paler 

 towards the middle ; flowers few ; base of the petals very 

 narrow ; stigmas undivided ; fruit without any prominent 

 dissepiments ; placeiitaries very short, almost disunited ; 

 seeds numerous, minute, ellipsoid. Figure 122. 



X. gracilis. 

 Paired sepals distinctly keeled. 



Rather tall ; leaves long, hardly ever twisted, compressed- 

 filiform ; flower-headlets usually globular-ovate, their axis 

 elongated ; bracts dark, lax, irregularly arranged in five 

 rows, glabrous, soon torn at the margin, the lower empty 

 and gradually smaller ; petals orbicular-obovate ; stigmas 

 globular ; fruit bursting transversely, producing three- 

 imperfect dissepiments ; placentaries highly extended, 

 downward somewhat united ; seeds numerous, minute. 



X. operculata. 



TYPH^CEAS. 

 TYPHA. 



1869. Upper spike often conspicuously separated from the 



lower. 



Quite tall, unbranched : leaves of soft texture, very long, 

 but narrow, plan-convex, blunt, without any prominent 

 venulation ; both spikes usually much elongated, but the 

 lower occasionally interrupted, the upper externally 

 yellowish, the other externally brown, both on the same 

 rhachis ; sepals and petals pappus-like ; stamens usually 

 three, somewhat connate ; stigma unilateral ; fruit quite- 

 concealed, oblique, narrowed into a stalk-like base. 



T. angustifolia. 



