Opening 



orbicular 



a thickening wliicli causes a hinge- 

 like motion of the cells themselves 

 (Schinz) ; cf. Lip-cells ; r^ of 

 Flow'ers, the expansion of the 

 members at the period of maturity ; 

 anthesis, 

 oper'colar, oper'calate, opercula'his 

 {operculum^ a lid), furnished with 

 a lid, as in many Mosses and 

 Myrtaceae ; Oper'cule, (l)the lamina 

 of the leaf of Sarracenix (Heckel) ; 



(2) the lid of the flower m Eucalyptus; 



(3) the Operculum of Mosses ; oper'- 

 ouliform (JorTna, shape), shaped like 

 a lid ; Oper'culum, (1) a lid or coyer 

 which separates by a transverse line 

 of divisioD, as in the pyxis, and 

 Moss capsules; (2) also in some 

 pollen grains ; (3) the cover of 

 certain asci, which falls away at 

 maturity (Traverso). 



oper'tus (Lat., hidden), the same as 

 tectus. 



opliioglossa'ceoas, akin to or resembling 

 Ophioglossum. 



oph'inre {p<pis, a snake ; ovpi, a tail) 

 Cells, used by Jonsson for Astro- 

 8CLEREIDS of Tschirch ; the liame 

 is from their resemblance to Echi- 

 noderms. 



ophryd'eouB, resembling or allied to 

 the genus Ophrys. 



opisthe'lial, an error for opis'thial 

 {orciaQios, hinder) Pore, Tschirch 's 

 name for the posterior border of a 

 stoma ; opis'thodal is a synonym ; 

 cf. EisoDAL ; opisthod'romous 

 {Zp6fxos, a course), a flower is so 

 termed when the genetic spiral 

 is assumed to pass on its shortest 

 way from the bract to the first 

 floral segment by the back of the 

 flower, between it and the axis of 

 the stem. 



O'pium (Lat., dried poppy-juice), 

 the conciete juice from the cap- 

 sules of Papaver somniferum, 

 Linn. ; '-' Al'kaloids are numerous, 

 the best known being Morphia. 



Opi'um (oirioj', poppy juice), a parasitic 

 plant formation ; opoph'ilus {<pi\fa>, 

 I love), sap-loving ; Opophy'ta {(pvThv, 

 a plant), parasites (Clements). 



Oplarlam {SirXdpia, arms), Necker's 

 word for Scyphus. 



Opporta'nism {opportunus, con- 

 venient), the direction in meta- 

 morphosis due to the factors potent 

 at the moment (Ganong). 



op'posite, cppositus (Lat., standing 

 in front) ; (1) set against, as leaves 

 when two on one node ; (2) one 

 part before another, as a .stamen in 

 front of a petal ; opposi'te-pin'nata8» 

 with leaflets on the same plane at 

 right angles to the common petiole ; 

 oppositiflor'us {jios^floris, a flower), 

 having opposite peduncles ; opposi- 

 tifo'lions {folium, a leaf), (1) with 

 opposite leaves ; (2) opposite a 

 leaf, as a tendril ; oppositipet'- 

 aloas, ~lus (ttctoAoj', a flower-leaf), 

 placed before a petal ; oppositisep'- 

 alous (+ Sepal), situated before a 

 sepal ; oppositi'vus (Lat.), when 

 one part stands before another, the 

 reverse of "alternate." 



Opseosper'mata (o»|/fy, o^'cws, sight ; 

 atrfpfxa, a seed), tubercles on the 

 surface of some Algals containing 

 spores (Lindley). 



Opsig'ony {6\^iyovos, posthumous), the 

 production and development of 

 proventitious buds (Wittrock) ; cf. 

 Prolepsis. 



•opsis (oif/^s, appearance), employed for 

 those Fungi in which uredospores 

 are rare or wanting, the aecidium 

 giving rise to teleutospores, e.g. 

 Pucciniopsis. 



op'timal {optimus, best), the most 

 advantageous for an organism or 

 function ; Op'timum refers to the 

 degree of temperature, light, etc., 

 which best conduces to the vital 

 activities of a given organism. 



Opulastera'num, a "layer" of Opu- 

 laster (Clements). 



O'rae {ora, extremity) Radi'cam % — 

 Spongioles. 



Or'ange, (1) the fruit of Citrus Aur- 

 anthcm, Linn.); (2) a secondary 

 colour, red and yellow combined, 

 taking its name from the tint of 

 the fruit mentioned. 



orbic'ular, orhicula'ris (Lat., cir- 



258 



