Oonucleus 



oppositifolioua 



a mushroom), those Fungi which 

 reproduce sexually by antheridia 

 and oogonia, the result being an 

 oospore (Tubeuf) ; Oonu'cleus ( + 

 NUCLEUS), the nucleus of an 

 oosphere, cf. SPERM - NUCLEUS ; 

 O'ophore (<t>opew, I carry), the 

 OOPHYTE in Archegoniatae ; Oopho- 

 ridan'gia (dyye'iov, a vessel), J. 

 Smith's name for the macro- 

 sporangia of Marsilea, etc ; Oo- 

 phorid'ium, a sporangium contain- 

 ing macrospores in Selaginella ; 

 O'ophyte (<f>vr6v t a plant), that 

 portion of the life-cycle of a plant 

 during which it bears sexual organs; 

 the same as OOPHORE ; O'oplasm 

 (7rXdcr/ia, moulded), the protoplasm 

 of the oosphere ; O'osphere (r0atpa, 

 a globe), a naked and nucleate 

 mass of protoplasm, which, after 

 coalescence with the sperm-nu- 

 cleus, develops into an oosperm ; 

 the egg or ovum ; Com' pound ~ , 

 one which contains several or 

 many functional sexual nuclei, as 

 in Albugo (Stevens); O'o sperm 

 (ffirepfjuL, seed), the product of the 

 fusion of a male and a female 

 cell; Oosporan'ge = Oosporan'- 

 gium, pi. Oosporan'gia (vtropa, a 

 seed, ayyetov, a vessel), the sacs or 

 sporangia which produce oospores ; 

 O'ospore, the immediate product 

 of fertilisation in an oophore ; 

 Oothe'ca (077*07, a case), the theca 

 or sporangium of Ferns. 



opa'cus (Lat., shady, giving shade), 

 (1) not transparent; (2) dull, not 

 shining; opake and opaque are 

 anglicised forms of the word. 



o'pen, not closed ; as ~ Bun'dle, one 

 which retains a portion of cam- 

 bium capable of further differen- 

 tiation ; opposed to closed bundle ; 

 ~Nu'cleus, the nucleus of Cyano- 

 phyceae (Hieronymus). 



O'pening, expanding or becoming 

 unclosed; ~ Cells, those special 

 cells by which the dehiscence of 

 sporangia and pollen-sacs takes 

 place (a) either by tangential 

 contraction on drying, or (6) by 



a thickening which causes a hinge- 

 like motion of the cells themselves 

 (Schinz) ; cf. LIP-CELLS ; <~ of 

 Flow'ers, the expansion of the 

 members at the period of maturity ; 

 anthesis. 



oper'cular, oper'culate, opercula'tus 

 (operculum, a lid), furnished with 

 a lid, as in many Mosses and 

 Myrtaceae ; Oper'cule, the lamina 

 of the leaf of Sarracenia (Heckel) ; 

 oper'culiform (forma, shape), 

 shaped like a lid ; Oper'culum, a 

 lid or cover which separates by 

 a transverse line of division, as 

 in the pyxis, and Moss capsules ; 

 also in some pollen grains. 



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

 tectus. 



opisthe'lial, an error for opis'tMal 

 (dirlffdios, hinder) Pore, Tschirch's 

 name for the posterior border of a 

 stoma ; opis'thodal is a synonym ; 

 cf. EISODIAL ; opisthod'romous 

 (dpo/JLos, a course), a flower is so 

 termed, when the genetic spiral 

 is assumed to pass as 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. 



oph'iure (#0is, a snake, otfpci, a tail) 

 Cells, used by Jonsson for ASTRO- 

 SCLEREIDS of Tschirch ; the name 

 is from their resemblance to Echi- 

 noderms. 



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

 the concrete juice from the cap- 

 sules of Papaver somniferum, 

 Linn. ; ~ Al'kaloids are numerous, 

 the best known being Morphia. 



Oplar'ium (oTrXdpia, arms), Necker's 

 word for SCYPHUS. 



op'posite, opposi'tus (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-pinn'atus, 

 with leaflets on the same plane at 

 right angles to the common petiole; 

 oppositiflor'us (flos,floris, a flower), 

 having opposite peduncles ; opposi- 

 tifo'lious (folium, a leaf) ; (1) with 



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