696 P0TYG(5NACE^. (BtJCKWHEAT FAMILY.) 



Ochreae membranous, short-bilobed. Leaves usually minute, soon 

 deciduous. Flowers few, clustered in the axils of the ochreae, on 

 jointed pedicels. ' 



1. C. coinosiiiii, L'her. 5 Hosali. lilsu. Arid. 3 to 5, glabrous; 

 branches white, tortuous. Leaves hardly .003 long, subulate, adnate 

 to oclirecG. Akene ovate, bristles in 12-16 rows, branching, soft, dilated 

 at base, more or less joined into 4, short wings — April — Syria; Ghor- 

 e.>-Safieh to Sinai and Egypt, 



2. C. polygonoic1c§, L. ^ o to 5, glabrous; branches 

 slender. Leaves .006 to .01 long, subulate, free from ochrece, soon 

 deciduous. Akene oblong, bristles rigid, branching, dilated at base, 

 more or less joined in short wings — Spring — Southern and eastern 

 Deserts (Tristram). 



2. RHEUM, L. RnuBARB. EiMs. 



Flowers perfect. Perigonium herbaceous, 6-parted, marcescent, 

 with nearly equal lobes. Stamens 9, inserted at bottom of calyx. 

 Ovary free, triquetrous, styles 3, short, spreading, stigmas entire, dis- 

 coid. Akene samaroid, 3-winged-angled, much longer than appressed 

 perigonium. Seed erect, embryo straight in axis of mealy albumen, 

 radicle short, superior — Coarse herbs, with a thick rhizome, thick, 

 short, annual stems, and broad, palminerved leaves. 



R, Ribcs, Gronov. 2f MMs. 1 or more, stem leafy below, 

 leafless above, ending in a broad, clustered panicle. Leaves glauces- 

 cent, leathery, cordate-orbicular to reniform, .2 to .8 broad, denticulate, 

 coarse-nerved, nerves papillose below. Pedicels clustered, filiform; 

 akene crimson, somewhat fleshy, cordate-ovate, .01 to .015 long, wings 

 2-3 times as broad as seed — May — Moab; subalpine and alpine Leb- 

 anon ; Amanus, and northward, and eastward. 



3. OXYRIA, Hill. Mountain- Sorkel. 



Flowers perfect. Perigonium herbaceous, 4-parted, marcescent, 

 the inner pair of sepals broader, at length appressed to akene, the 

 outer pair reflexed. Stamens 6, a pair opposite each outer sepal, and 

 a single one opposite each inner. Ovary compressed, stigmas two, 

 nearly sessile, penicillate. Akene lenticular, membranous, surrounded 

 by a broad, translucent wing. Seed compressed, erect. Embryo in 

 axis of mealy albumen, radicle straight, superior — Tender, low, 

 alpine herbs. 



O. iMgyua, L. 2^ .01 to .035; neck much branched, scaly from 

 old ochreae and petioles; stems nearly leafless, ending in a simple 

 raceme or meagre panicle. Leaves cordate-orbicular to reniform, .01 

 to .025 broad, long-petioled, sometimes obsoletely 3-lobed. Pedicels 

 filiform, jointed about middle, somewhat longer than fruit; akene 

 orbicular, cordate at base, .003 long, more or less incised at tip, wing 

 purple, transversely veined, as broad as seed or broader — Late sum- 

 mer — Alpine Lebanon. 



4. ERIEX, Neck. Emex. 



Flower monoecious - polygamous. Staminate. Perigonium her- 

 baceous, 3-0-partcd, lobes equal, spreading. Stamens 4-6. Pistillate. 



