829 



Cijc CrnuSurii of SSotang. 



OWAL 



outer three of which resemble a calyx, the 

 inner a corolla ; there are from six to 

 twelve stamens, six stigmas, and a six to 

 eight-celled berry, with numerous seeds. 

 The seneric name is derived from the Ma- 

 labar Ottel-ambel. [B. S.] 



OTTOA. A genus of umbellifers, distin- 

 guished by its calyx being destitute of 

 border: by"Its entire petals, its spreading j 

 styles, and by each half of the fruit having j 

 five membranous rib«. The only species is 

 O. cenanthoides, a native of Quito, which 

 lias a simple stem with fine leaves, which 

 I are round and hollow within, with trans- 

 verse partitions : the flowers white, in 

 j dense umbels, a few with stamens and pis- 

 I tils and therefore perfect, the others with 

 ; stamens only. The genus was named in 

 honour of F. Otto, of Berlin. [G. D.] 



OTTO or OTTAR OF ROSES. A fra- 

 grant oil obtained from Rosa centifolia and 

 E. damascena. 



OURARI. The Wourali or Urari poison, 

 the basis of which is the juice of Strychnos 

 toxifera. 



OUTLINE. The figure formed by the 

 margin of a body. 



OUVIRANDRA. The genus of Juncagi- 

 nacece,to which belong the singular aquatic 

 Lace-leaf or Lattice-leaf plants of Mada- 

 gascar. It is closely allied to Aponogeton, 

 from which it principally differs in its seeds 

 having a thick leafy cotyledon embracing 

 a two-leaved plumule, and in its sepals 

 being deciduous. The habit of the two ge- 

 nera also is different. Only three species 

 were originally referred to Ouvirandra, two 

 from Madagascar and one from Senegam- 

 bia : but four other Indian species possess- 

 ing the technical characters of the genus, 

 though previously referred to Aponogeton, 

 are now included in it. All these plants 

 are aquatic herbs, with tuberculate roots, 

 radical submerged leaves, and a scape or 

 flower-stalk long enough to reach the sur- 

 face of the water, where it either bears a 

 single spike or divides into from two to 

 five little spikes of small flowers. These 

 have two or three coloured deciduous se- 

 pals, six persistent stamens with wide- 

 based filaments, and three or four one- 

 celled ovaries ending in short styles. 



The two most remarkable species are 

 those of Madagascar, 0. fenestralis and 0. 

 Bernieriana, both of which have within 

 the last ten years been introduced into oar 

 hothouses by the Rev. H. Ellis, well known 

 through his missionary labours in that is- 

 land. The former is best known as the 

 Lattice-leaf plant, from its singular leaves 

 resembling open lattice-work, or apparent- 

 ly consisting of only a skeleton of nerves. 

 These leaves grow in radiating clusters 

 from the rhizome, and float just beneath 

 the surface of the water, presenting a flat 

 side to the light. They have rather long 

 stalks, and are of an oblong form, rounded 

 a: both extremities, very variable in size, 

 i but usually nine inches to a foot long by 

 1 two or three inches broad. "When super- 



ficially inspected they seem to be composed 

 simply of a stout midrib and several slen- 

 der longitudinal nerves parallel with it all 

 connected by numerous short cross-nerves, 



Ouvirandra fenestralis. 



and to be wholly destitute of the paren- 

 chyma or cellular tissue with which the 

 spaces between the nerves in ordinary 

 leaves are closed up ; but the microscope 

 shows that this cellular tissue is really 

 present, surrounding the nerves, and in 

 the very young state of the leaf the spaces 

 are nearly, if not quite, filled up by it. The 

 flower-stalks rise from the centre of the 

 tuft of leaves, and fork into a couple of 

 spikes at the top. The plant, however, is 

 not only curious, but is a valuable one to 

 the natives of Madagascar, who collect 

 its fleshy farinaceous roots as an article 

 of food, calling the plant, on this account, 

 Ouvirandram, which means literally Water- 

 Tarn, and this is the source of the generic 

 name. It grows on the margins of running 

 streams in shallow water. [A. SJ 



OVAL. The same as Elliptic. 



OVARY. That part of the pistil which 

 contains the ovules. 



OVATE. Oblong or elliptical, broadest 

 at the lower end, so as to resemble the lon- 

 gitudinal section of an egg. 



OVEXCHTMA. Oval cellular tissue. 



OVERLOOK. A name given by the West 

 Indian negroes to Canavalia gladiata. 



OVIEDA. Lapeyrousia. 



OVOIDAL. A solid with an ovate figure, 

 or resembling an egg. 



OVULE, OVUM. The young seed. 



OVULE TUBE. A thread-like extension 

 of the apex of the nucleus, or of the sac of 

 the amnios, rising up beyond the foramen. 



OWALA. Pentaclethra macroplu/Ua, the 

 seeds of which furnish a useful oil, and 



