Oonucleus 
oppositifolious 
@ mushroom), those Fungi which 
reproduce sexually by antheridia 
and oogonia, the result being an 
oospore (Tubeuf); Oonu’cleus (+ 
Nvcievs), the nucleus of an 
oosphere, ¢f. SPERM - NUCLEUS; 
O’ophore (gopéw, I carry), the 
OoruyTs in Archegoniatae; Oopho- 
ridan’gia (dyyeiov, 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 (¢urov, a plant), that 
portion of the life-cycle of a plant 
during which it bears sexual organs; 
the same as OoPHoRE; O’oplasm 
(wAdopua, moulded), the protoplasm 
of the oosphere ; O’osphere (cpaipa, 
a globe), 4 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’osperm 
(orépya, seed), the product of the 
fusion of a male and a female 
cell; Oosporan’ge = Oosporan’- 
gium, pl. Oosporan’gia (cropi, a 
seed, dyyelov, a vessel), the sacs or 
sporangia which produce oospores ; 
O’ospore, the immediate product 
of fertilisation in an oophore; 
Oothe’ca (A7jxn, 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 ~ Bundle, 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 (b) by 
176 
a thickening which causes a hinge- 
like motion of the cells themselves 
(Schinz); cf. Lip-cetus; ~ 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’thial 
(érteOcos, hinder) Pore, Tschirch’s 
name for the posterior border of a 
stoma; opis’thodal is a synonym ; 
cf. EISODIAL;  opisthod’romous 
(pduos, 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 (é¢is, a snake, ovpa, a tail) 
Cells, used by Jinsson 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 (érAdpia, arms), Necker's 
word for ScyPuus. 
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 ofa petal; opposi’te-pinn’atus, 
with leaflets on the same plane at 
right angles to the common petiole; 
oppositifior’us (los, floris, a flower), 
having opposite peduncles; opposi- 
tifo’lious (folium, a leaf); (1) with 
