feces of the le&ves v/hen the plan ' -it rest. 



This P-enus is readily distinguished from nearly all others 

 of ITesembryanthemum tribe by its dwerf, stenless habit, sub- 

 p-:lobose or comnressed-obovoid or oblong f:rov.;ths of firm sub- 

 stance, vrith the tv7o leaves of v-hich they are cor.r osed closed 

 tightly together durlnp- the resting period. The only genere 

 with vrhich it can be confused are ^ibbaeum and ^iayTnaotus. 

 "^ron those fev? species of Gibbeeun that have equal or subequal 

 leaves, the firmer substance of the growths, end the more numer- 

 ous (7-15) stiCTias, valves end cells of the ovary cell distin- 

 guish it; and from Didymaotus, the absence of dots upon the 

 growths, the central (not lateral) flo^;ers and more numerous stig- 

 mas readily separate it. The sectional structure of the flov/er 

 resembles that of lithons, hut in is vegetative character, more 

 numerous stiP-mas and cells of the ovary, and especially by the 

 presence of cell-wings roofing the cells of the carssule, it is 

 ver:^ different. 



The diagramatic figures (^ig. 66) showing the structure of 

 this genus are not drawn to enj scale; the figure of the capsule 

 is about one-and-a-half times natural sjze. 



KEY TO THE SPECIES. 



1. --Surface o" the rov/ths microscor^icol.ly puberulous, vel- 

 vety to the touch; leaves or lobes with minute teeth 

 on their edges end often p long the faint keel. 



3, Hoodiae, 



Surfpce of the growths glabrous, no teeth. 2 



2. — Surface faintly rugulose end microscopically granulate, 



of £' light dove-grey colour. 4, f'ole -3vansii 



Surface smooth, v;hitish, glaucous-green, or of a pale 



reddish tint. 3 



3, — Gro\7ths 1-1 3/4 inch high, 8-15 lines broad and 6-10 



lines thick; flowers v/hite. 1, Heathii. 



Growths i-1 inch high, 4-8 lines bropd. and 3-6 lines- 



thick; flowers unknown. 2, dubia. 



1.— R. Heathii, N. 3. Bp. (Figs. 66,6?). Rootstock thick, 

 deeplv descending. Growths crowded upon the top of the rootstock, 

 or, under cultivation, st the ends of short prostrate br-rnches, 

 sub'-iohQ-e pnd from 1-2 inches in diemeter or comrressed obovoid 

 and 1-1* inch high, 8-15 lines broad and 6-10 lines thick, with 

 the fissure bet^ een the leeves 5-8 lines deep, and the top of 

 the leaves rounded or faintly keeled, quite entire, smootti, glab- 

 rous, uniforml:?" whitish to pale glaucous-green, or sometimes 

 tinted brownish or reddish, ivithout spots or other ma.rkings. t'ed- 

 ic'el equsTling or slightly exceeding the grov.'ths, stout, flrttened 

 vn'.th acute edges and 6-7 lines bror d, glabrous, ^eljx compressed, 

 subenuplly 8-9-lobed, glabrous; lobes 3-4 lines long, 2-2?, lines 

 hro^'d, oblong, obtuse, mostly with membranous edges. Oorolla 14- 

 18 lines in diameter, expanding about mi''"-day and closing at the 

 l-t^pr ^evt o"f thf afternoon; petals numerous, in "-4 series, 

 ''ree, subequcl, 7-9 lines long and in *-£ line bror d, linear, ob- 



