Ontogeny 



Opening 



Ontog'eny {oura, things existing ; 

 7eVos, race, offspring), tlie develop- 

 ment of an indiviJiMl in its various 

 stages ; adj. ontcgenet'ic. 



ooblas'tic {ilihv, an egg^ fixaarhs, a 

 bud) Fil'aments, see next ; Ooblas- 

 te'ma {&\daTr},ua, a sprout), Fil'a- 

 ments, the Fertilizing Tubes of 

 Schmitz ; O'ocyst {Kvatis, a bag), 



(1) a female organ, an Oogonium ; 



(2) Vuillemin's term for an envelope 

 of the egg which is due to the cells 

 composing that structure ; Ooga- 

 m'ete (+ Gamete), a female gamete 

 (Hartog); oog'amous {y^/^os, mar- 

 riage), conjugation in which the 

 two coalescing gametes are of dis- 

 similar form ; Oog'amy, the reverse 

 condition of Isogamy ; the female 

 gamete never active, the male a 

 spermatozoon, and the product an 

 Oosperm (Hartog) ; Oogem'ma 

 {gemma, a Ijud), Camel's term for 

 Archegonium ; Oogen'esis {jfyeais, 

 beginning), (1) the formation of the 

 OosPHERK, the early stage of the 

 ovule ; (2) the differentiation of a 

 large resting ceil (oos})hcre) to fuse 

 ■with a small motile cell (sperm) 

 into a zygote (Hartog) ; O'ogone, 

 Oogo'niwii, pi. Oogo'nia {yoyij, race, 

 offspring), a female sexual organ, 

 usually a spherical sac, contain- 

 ing one or more oospheres ; 

 oogo'nial Tube = Neok-canal ; 

 ookinet'ic (/ciVtjtj/cos, putting in 

 motion), tending to produce the 

 female element ; Corysis {\vais, a 

 loosing), viridescence, especially in 

 carpels and ovules (Penzig) ; Oomy- 

 ce'tes (nvKT]s, a mushroom), those 

 Fungi whieli reproduce sexually by 

 antheridia and oogonia, the result 

 being an oospore (Tubeuf). 



O'dn {u}hv, an egg), proposed as an 

 equivalent of Egg (P. F. Myles) ; 

 Oonang'ium, the embryo sac (Radl- 

 kofer) ; Oone'ion (vtjIs, a nymph), 

 Radlkofer's term lor Archego- 

 nium ; O'onyle (wAt], raw material), 

 the unfertilized female organ of 

 any sort (Radlkofer) ; Oonu'cleus 

 (-f Nucleus), the nucleus of an 



oosiihere, cf. Si'f.RM - nucleus ; 

 O'ophore {(popiu, I cai-ry), the 

 OoPHYTE in Ai'chegoniatae ; Oopho- 

 ridan'gia {ayyelov, a vessel), J. 

 Smith's name for the macro- 

 sporangia of Marsilea^ etc. ; Oo- 

 pbcrid'ium, a sporangium contain- 

 ing raacrospores in Selaginella ; 

 O'opbyte {<pvrhv, a plant), that 

 portion of the life-cycle of a plant 

 during which it bears sexual organs ; 

 the same as Oophork ; O'oplasni 

 {iT\(i(Tfxa, moulded), the protoplasm 

 of the oosphere ; ooplasm'ic, relat- 

 ing to the ooplasm ; O'oplast, Ker- 

 uer's terra for Oosphere ; O'osperm 

 {a-jrfpfia, seed), the product of the 

 fusion of a male and a female cell ; 

 O'osphere {a-faipa, a globe), a naked 

 and nucleate ma.ss of protoplasm, 

 which, after coalescence with the 

 s[>erm-nucleus, dev^elops into an 

 oosperm ; the egg or ovum ; Com'- 

 poucd '-'jone which contains several 

 or many functional sexual nuclei, 

 as in Albugo (Stevens) ; oospbe'ric, 

 relating to the Oosphere ; Oospor- 

 an'ge = Oosporan'gium, pi. Oospor- 

 an'gia {<nropa, a seed ; ayye'iov, a 

 vessel), the sacs or sporangia which 

 produce oospores ; O'ospore, the im- 

 mediate product of fertilization in 

 an oophore ; Oothe'ca {6-nKr], a case), 

 the theca or sporangium of Ferns. 



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

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

 shining ; opake and opaque are 

 anglicized forms of the word. 



o''pen, (1) not closed ; (2) expanded, 

 theopposite of DIFFUSE ; -- Bun'dle, 

 one which retains a portion of cam- 

 bium capable of further diff"eren- 

 tiation ; oppo.sed to clo.sed bundle ; ^ 

 Forma'tion, when the plants are 

 scattered (Clements) ; ~ Nu'cleus, 

 the nucleus of Cyanophyceae 

 (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 (b) by 



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