464 ONAGRACEAE 



Onagraceae. Dicotys (Archichl. Myrtiflorae). 36 gen., 480 sp., chiefly 

 N. temp, (see Epilobium). Most are perennial herbs, a few shrubs 

 or trees. L. alt., opp., or whorled, simple, rarely slip. Fls. sol. 

 in the leaf-axils or in spikes, racemes or panicles, $ , reg. or -|- , usu. 

 4-merous (sometimes 2 5). Axis prolonged beyond ovary into a 

 tube ('calyx-tube '). K 4, valv.; C 4, rarely o, usu. conv. ; A 4 + 4, 

 or 4, 2, or j ; G (4), 4-loc. with axile plac. and i oo anatr. ov. ; the 

 septa are commonly imperfect below ; style simple. The fls. are 

 mostly adapted to bees or Lepidoptera and are often markedly 

 protandr.; those of sp. of Lopezia are explosive. Fr. usu.aloculic. caps., 

 sometimes a nut or berry. Seeds exalbum. Many cult. orn. fl. 

 Classification and chief genera (after Engler) : 



r. Trapeae (ov. semi-inf., 2-loc. ; fr. thorny) : Trapa. 

 2. Oenothereae (ov. inf., 4 i-loc.): Epilobium, Jussieua, 

 Oenothera, Clark ia, Fuchsia, Lopezia. 



Oncidioda x . Orchidaceae. Hybrid, Oncidium-Cochlioda. 



Oncidium Sw. Orchidaceae (n. 19). 300 trop. Am., W.I. Some, 

 e.g. O. Papilio Lindl., have flat tubers which make humus- collecting 

 niches ; others have fleshy 1. and no tubers. Cult. orn. fl. 



Oncinocalyx F. Muell. Verbenaceae (i). i Austr. 



Oncinotis Benth. Apocynaceae (n. i). 10 trop. Afr., Madag. 



Oncoba Forsk. Flacourtiaceae (2). 30 trop. Am., Afr., Madag. 



Oncocalamus Mann et H. Wendl. Palmae (in), i W. Afr. 



Oncocarpus A. Gray. Anacardiaceae (4). 2 New Guinea, Fiji. 



Oncodostigma Diels. Anonaceae (2). i New Guinea. 



Oncosperma Blume. Palmae (iv. i). 6 Indomal. 



Oncostemma K. Schum. Asclepiadaceae (n. 3). i S. Thome. 



Oncostemon A. Juss. Myrsinaceae (n). 60 Madag., Mascarenes. 



Oncostylis Nees = Fimbristylis Vahl (BH.} = Psilocarya Torr. 



Oncotlieca Baill. Aquifoliaceae? Ebenaceae? i New Caled. 



Oncus Lour. Dioscoreaceae. i Cochinchina. 



Ondetia Benth. Compositae (4). i S.W. Afr. 



Ongokea Pierre. Olacaceae. i Gaboon. 



Onion, Allium Cepa L. 



Onobroma Gaertn. = Carduncellus Adans. (Comp.). 



Onobrychis L. Leguminosae (in. 7). 80 temp. Eur., As. Floral 

 mech. as in Trifolium. O. sativa Lam. (sainfoin) good fodder. 



Onoclea L. Polypodiaceae. i N. Am., N. As. 



Ononis L. Leguminosae (in. 4). 70 Medit., Eur. (3 in Brit.; rest- 

 harrow). Shrubs and herbs, sometimes with thorny lat. branches. 

 Mech. of fls. intermediate between Lotus and Trifolium. At first the 

 upper edges of the keel cohere, and the pollen is squeezed out at the 

 tip as in Lotus ; afterwards the keel splits and the anthers emerge as 

 in Trifolium. Cleist. fls. in some. 



Onopix Rafin. Compositae (inc. sed.). 2 Louisiana. 



Onopordon L. Compositae (i i ). 20 Eur. , N. Afr. , W. As. 0. Acan- 

 thium L. (cotton thistle) in Brit. L. decurrent. 



Onoseris DC. Compositae (12). 18 S. Am., Mexico. 



Onosma L. Boraginaceae (iv. 4). 75 Medit., Himal. 



Onosmodium Michx. Boraginaceae (iv. 4). 6 N. Am. 



Ontogeny, development of the individual. 



