47 



Opbb'culatb, Opbrculatus— Covered by a 

 lid; closed by an "oper'oulutn," as 

 the Eucdypt flowers before expansion. 

 Op'positb — When similar parts or organs 

 are so arranged in pairs that one of 

 them is immediately on the opposite 

 side of some interposed body, or of the 

 axis about which they are disposed. 

 Oppositiflo'bcs — Where the peduncles 

 are opposite. Oppositipol'eus — Where 

 tHe leaves are opposite. 



Obangb— Yellow and red in about equal 

 proportions. 



Obbic'ulak, Okbioula'ris— Perfectly or 

 very nearly circular. Oebioulus — A 

 description of fleshy "corona ""eur- 

 loundmg the organs of fructification 

 in the genus Stapelia. 



Oroan — ^A general name for any defined 

 subordinate part of the vegetable struc- 

 ture, external or internal ; as cell, fibre, 

 leaf, root. Every portion of a plant 

 which has a distinct part or function to 

 perform in the operations or phenomena 

 of vegetable life is called an organ. 

 The root, stem, and leaves, whose 

 function is to assist in the growth of 

 the plant, are Organs of Vegetation. 

 The flower and fruit, whose office is 

 the formation of the seed, are Organs 

 ef Reproduction. 



OrGANOG-'EAPHY — That part of botany 

 which treats on the organs of plants 



Obqt'a — From 5 to 6 feet. A tsise. 

 Oesta'lis — ^The length of a toise. 



OR'iriOE — An opening, as the top of a 

 corolla-tube. 



Oktho'tropal, Ortho'tropous, Ortho'- 

 TBOPns — Where the embryo is straight, 

 but so lies in the seed that the radicle' 

 is towards the hilum, owing to the 

 inversion of the nucleus. This term is 

 also applied to the entire ovule _ or 

 seed, without reference to the position 

 of the embryo; when the nucleus is 

 straight, and the ohalaze and hilum 

 correspond or are close together, and 

 consequently where the direction of 

 the embryo is " antitropal," or the very 

 reverse of that here described. 



Oscilla'nus, Oscillato'rius — Synonym 

 for"Versatilis.". 



Os'mose, Os'mosis— See "Endosmosis."' 



OSTIO'LTJM— The orifice of the perithecium 

 and apothecium. 



Os'sEons— Synonym for " Bony." Ossicu- 

 LUS— A"stone" in fruit; synonym for 

 "Pyrena." OsTARiPHTLDM— A plant 

 which bears a drupe. 



Ova'lis, O'val— Elliptical. Where the 

 major and minor axes bear the ratio of 

 about two to one to each other. OVATE, 

 OVAIDS— Shaped like an egg. Of the 

 form of an egg, when applied to a solid 

 body ; but when applied to a superficial 

 area it means the figure presented by a 

 longitudinal section of an ^gg, broader 

 at the base than at the apex; some- 

 times used synonymously with "Oval.' 

 Ovoid', Ovoi'dal, Ovoi'deus, Ovu- 

 liA'Bls, are synonymous with " Ovate," 

 when applied to a solid form. The 

 leaves of the common Lantana bush are 

 mostly ovate. 



O'VART — The enlarged base of the pistil, 

 which includes one or more cavities or 

 cells, containing one or more small 

 bodies called oyules. These are the 

 earliest conditions of the future seeds. 

 Each ovule, when fully formed, usually 

 consists of a central mass or nucleus 

 enclosed in two bag-like coats, the outer 

 one called primime, the inner one 

 seeundine. The ehalaza is the point 

 of the ovule at which the base of 

 the nucleus- is confluent with the 

 coats. The foramen is a minute 

 aperture in the coats over apex of the 

 nucleus. 



O'VULES are orthotropous or straight, when 

 the ehalaza coincides with the base of 

 the ovule, and the foramen is at the 

 opposite extremity, the axis of the 

 ovule being straight ; eamvpylotropous 

 or incurved, when the ehalaza still 

 coinciding with the base of the ovule, 

 the axis of the ovule is curved, bringing 

 the foramen down more or less towards 

 that base ; anatropous or vn/verted, when 

 the ehalaza is at the apex of the ovule, 

 and the foramen next to its base, the 

 axis remaining straight. In this, one 

 of the most frequent forms of the 

 ovule, the ehalaza is connected with 

 the base by a cord, called the raphe, 

 adhering to one side of the ovule, and 

 becoming more or less incorporated 

 with its coats, as the ovule enlarges 

 into a seed ; amphitropous or half- 

 inverted, when the ovule being, as it 

 were, attached laterally, the ehalaza 

 and foramen at opposite ends of its 

 straight or curved axis, or about equally 

 distant from the base or point of 

 attachment. 



Oxyaoan'thus — Eurnished with many 

 sharp thorns or prickles. 



Oxycab'pus — Where the fruit is sharp- 

 pointed. 



Pach'ts— Thick, as Paohiden'dbon, thick 

 tree; Paohycar'phs, where the peri- 

 carp is very thick ; Pachyne'ma, re- 

 ferring to the filaments of certain 

 flowers being thick, 



Pagi'na — The upper or under surface of 

 flat-leaves. 



PALA'cEOna; Pala'cbub— When 'the edges 

 of any organ, but more especially the 

 margins of a leaf, adhere to the sup- 

 port. 



Pal' ate, Pala'tum — The'inferior surface of 

 the throat in rinsent and personate 

 corollas, where it is elevated into two 

 longitudinal ridges, with a depression 

 between them. 



Pa'le^, Pales, or Chaff are the inner 

 bracts or scales in Compositae, Gram- 

 inese, and some other plants, when of a 

 thin yet stiff consistence, usually narrow 

 and of a pale colour. Palba'obous — , 

 Of a chaffy consistence. 



Pal'lidus— Pale ; with very plight tinge 

 of colour. 



