Plastogamy 
pleuroblastic 
ment of the entire protoplasmic 
cell-contents, including the nucleus 
and the chromatophores (Zach- 
arias); Plastog’amy (ydjos, mar- 
riage), the fusion of cytoplasts 
into a plasmodium, the nuclei 
remaining distinct (Hartog) ; adj. 
Plastogam’ic; Plastog’eny (-yévos, 
race, offspring), when cytoplastic 
elements undergo a reorganisation 
by fusion (Hartog);  Plas’toid 
(eldos, likeness), a needle-shaped 
body found in the stalk-cells of the 
tentacles of Drosera, becoming 
rounded under stimulus; a rhab- 
doid, 
Plate, a flattened structure; ¢f. 
NUCLEAR ~, SIEVE ~. 
Plateau’ (Fr.), (1) the tubercular disk 
in a bulb which produces the 
scales upwards, and the roots 
downwards, cf. Corm (Crozier) ; 
(2) a similar structure in certain 
Compositae, interposed between 
the ovary and the other floral 
organs (Lecoq). 
platycar’pic, platycar’pous (dards, 
broad, xapmds, fruit), broad-fruited ; 
Platylob’eae (AoBds, a lobe), used 
for certain Crucifers with flat coty- 
ledons ; platylo’bate, broad-lobed ; 
platyphyl'lous (¢v\d\ov, a leaf), 
broad-leaved. 
Plecolep’is, { Plecolep'idus (wdéxw, I 
plait, Aerts, a scale), the involucre 
of Compositae when the bracts 
are united into a cup. 
Plectench’yma (m\exrés, woven, 
éyxuua, an infusion), a tissuo of 
woven hyphae; a _pseudo-par- 
enchyma, further divided into 
PARAPLECTENCHYMA and Proso- 
PLECTENCHYMA (Lindau). 
Pleioblas’tus (w\efov, more, BdacTds, 
a bud), used by Koerber for those 
Lichen spores which germinate 
at several points; Pleiochas’‘ium 
(xdots, separation), each relative 
main axis of a cyme producing 
more than two branches; adj. 
pleiochas'ial; pleiocy’clic (kvx)os, 
a circle), perennial, as ~ Herbs; 
Pleiom’ery (uépos, a part), having 
200 
more whorls than the normal 
number; Pleiomor’phism, Pleio- 
mor’phy (u“opp7, change), the oc- 
currence of more than one inde- 
pendent form in the life-cycle of 
a species; Pleiont‘ism, Delpino’s 
term for PotymorpHy; pleio- 
phyl'lous, -/us (@vAdov, a leaf), with 
leaves having no apparent buds 
in their axils; Plefophyl'ly, having 
numerous leaves from the same 
point, or more than usual the 
number of leaflets in a compound 
leaf; Pleiopyre’nium (+ PyRENIUM), 
small apothecia in one verruca, in 
Lichens ; pleiosper’mous (o7répua, 
a seed), with an unusually large 
number of seeds ; Pleiotax’is, Pleto- 
tax’y (raés, order), increase in the 
number of whorls in a flower; 
Pleiotrache’ae (+ TRacuzga), 
‘“‘membranous tubes or tracheae 
containing a compound spiral 
fibre” (Cooke); Pleiox’eny (éévos, 
a host or guest), where a parasite 
can invade several species of host- 
plants (De Bary). 
ple’‘nus (Lat.), full, as Flos plenus 
= a double flower. 
Pleochro’icism (mhéov, more, xpda, 
colour, complexion), with various 
colours in the cell-wall ; syn., Pleo- 
chro’mism (xpéua, colour), adj. 
pleochro’ic, pleochrois’tic; Pleo- 
mor’phism, Pleomor’phy (op¢i, 
shape),the same as PLEIOMORPHISM. 
Ple’on, Naegeli’s term for an aggre- 
gate of molecules, but smaller than 
a Micenya. 
Ple’onasm (m)edvacua, a surplus), 
redundance in any part (Crozier). 
Ple’‘rome (7\jpwua, that which fills), 
the cylinder or shaft of a growing 
point enclosed and overarched by 
periblem; ~ Sheath = BunpLe- 
SHEATH. 
plesiomor’phous (7Anolos, near, uopph, 
shape), nearly of the same form 
(Crozier). 
Plew’ra (7)evpd, a side or rib), the gir- 
dle or hoop of Diatoms (0. Mueller) ; 
Pleurench'yma (@yyuuo, an infu- 
sion), woody tissue ; pleuroblas’tic 
