OBVO] , 



Efje CrcasSurji of 25fltattg. 



800 



horns of the crescent projecting forwards 

 instead of backwards. 



OBVOLUTE, OBVOLUTIVB. When 



the margins of one organ alternately over- 

 lap those of an opposite organ. 



OCA. The Peruvian name for the tuber- 

 bearing Osealis crenata andtitberosa. 



OCELLATED. When a broad round spot 

 of some colour has another spot of a diffe- 

 rent colour within it. 



OCHNA. A genus of trees or shrubs, 

 natives of Asia and tropical Africa, and 

 giving its name to the order Ochnacece. 

 Their leaves are provided with two axillary 

 deciduous stipules, and their flowers yel- 

 low, in racemes, with stalks jointed near 

 the middle. Calyx of five deciduous colour- 

 ed sepals ; petals five to ten, much larger 

 than the sepals; stamens numerous, the 

 anthers opening lengthwise. The lobes of 

 the ovary equal the petals in number, and 

 are placed obliquely upon a thickened re> 

 ceptacle, each containing a single ascend- 

 ing ovule. The style is single, divided 

 into five or ten branches. The fruits suc- 

 culent, of five, ten or fewer carpels placed 

 on the enlarged receptacle. [M. T. MJ 



OCHNACE.E. (Ochnads.)' A natural or- 

 der of thalamifloral dicotyledons belong- 

 ing to Lindley's rutal alliance of hypogy- 

 nous Exogens, consisting of uudershrubs 

 or trees, with alternate simple stipulate 

 leaA r es and articulated pedicels ; sepals 

 five, persistent, imbricated; petals imbri- 

 cated, asmany or twice as many, deciduous ; 

 stamens five opposite the sepals, or ten, 

 or indefinite, rising from an hypogynous 

 disk ; anthers bilocular, innate, opening 

 by pores, or longitudinally ; carpels as 

 many as the petals, seated on an enlarged 

 gynobase or torus. Fruit gynobasic, con- 

 sisting of several succulent indehiscent 

 monospermous carpels. They grow in tro- 

 pical countries, and are remarkable for 

 their large succulent torus ; they are gene- 

 rally bitter, and some of them are used as i 

 tonics. There are six genera, including J 

 Ochna and Gomphia, and upwards of eignty 

 species. [J. H. B.] 



OCHRA, or OCHRO. Abelmoschus escu- 

 lentus. —, AFRICAN, or AUTUMNAL. 

 Abelmoschus Bammia, probably a variety of 

 the preceding. — , BUN. Urena lobata. — , 

 MUSK. Abelmoschus moschatus. — ,WILD. 

 Malachra. 



OCHRACEUS. Ochre colour; yellow, im- 

 perceptibly changing to brown. 



OCHRADENUS. A genus of Resedacece, 

 distinguished by its fruit being a berry. 

 A small Egyptian shrub, with numerous 

 twiggy branches, linear obtuse leaves, and 

 spica'te yellow flowers, the peduncles at 

 length becoming spinescent. Calyx rotate, 

 five-toothed; petals absent; hypogynous 

 diskurceolate, the anterior limb truncate, 

 the posterior expanded into a lamina ; sta- 

 mens ten to twenty; berry ovate, three- 

 sided, one-celled, closed, with numerous 

 kidney-shaped seeds. [J. T. S.] 



OCHRANTHACE.E. The name under 

 which it was formerly proposed to separate 

 Ochranthe, a genus now included in C'uno- 

 niacece. 



OCHRANTHE. A genus of Cunoniacece, 

 consisting of a Chinese shrub, with the old 

 branches grey, the leaves stalked opposite 

 serrated, and furnished with ovate serru- 

 late interpetiolar stipules, and a terminal 

 panicle of white flowers, which turn yel- 

 lowish. Calyx of five coloured sepals, the 

 two exterior shorter; petals five, resem- 

 bling the sepals; stamens five, hypogynous; 

 disk fleshy.five-angled; ovary free, of three 

 united carpels. [J. T. S.] 



OCHREA. A tubular membranous sti- 

 pule through which the stem passes, formed 

 by the consolidation of two opposite sti- 

 pules ; as in Polygonum. 



OCHROLEUCUS. Nearly the same as 

 Ochraceus, but whiter. 



OCHROMA. The well-known Corkwood 

 tree of the New World, forms, with an 

 allied species, a genus of Sterculiacece, cha- 

 racterised by their flowers having a shortly 

 five-lobed calyx, surrounded by a three- 

 leaved involucel which soon drops off ; five 

 petals larger than the calyx ; the tubular 

 staminal column covered in the upper part 

 with narrow contiguous spiral one-celled 

 anthers, and five or ten-lobed at the top ; 

 and the five narrow stigmas spirally twisted 

 together. The five-celled fruit opens lon- 

 gitudinally through the cells, and contains 

 numerous seeds enveloped in silky wool. 

 Both species are trees, with leaves heart- 

 shaped at the base and angular or some- 

 what five to seven-lobed, and bear their 

 flowers at the ends of the branches. 



0. Lagopus grows about forty feet high, 

 and is very common, particularly along 

 the seashores, in the West Indies and Cen- 

 tral America, where its soft spongy and 

 exceedingly light wood, called Corkwood 

 in Jamaica, is commonly employed as a sub- 

 stitute for cork, both for stopping bottles 

 and for the floats of fishing-nets. The very 

 buoyant rafts or balsas, the unsinkable 

 properties of which caused such surprise 

 among the discoverers of America, are like- 

 wise made of it, whence the tree is called 

 Balsa in some parts of America. Its spe- 

 cific name Lagopus, signifying hare's foot, 

 alludes to the fruit, which is about a foot 

 in length and when ripe splits open by five 

 slits, out of which the silk-cotton of the 

 seeds protrudes and spreads over the whole 

 surface, giving it the appearance of a hare's 

 foot. The cotton is used for stuffing pillows 

 and cushions. [A. S.] 



OCHROPTERIS. A genus of polypodia- 

 ceous ferns, referred to the Pteridece, and 

 distinguished amongst those with free 

 veins, chiefly by the oblong transverse sori 

 being placed at the apices of the lobes, the 

 opposite condition from that which occurs 

 in Lonchitls, one of the genera of net-veined 

 Pteridece, in which the sori are placed in 

 the sinuses of the lobes. Pteris, which is 

 technically very closely allied to Ochropte- 



