prevernal 
Proecambium 
come) Buds, dormant eyes, pre- 
sent on any given portion of the 
stem, which produce epicormic 
branches (Hartig). 
prever’nal (pre, before, vernalis, of 
the spring), early spring flowering. 
Prick’le, outgrowths of the rind or 
bark, as those of the rose ; prick’ly, 
armed with prickles. 
pri’‘mary, prima’rius (Lat., chief), (1) 
used of the part first developed ; 
(2) the main divisions of a leaf or 
umbel; ~ Axis, the inain stem; 
~ Bast, consists of sieve tissues 
and parenchyma; ~ Cor’tex, the 
PERIBLEM ; ~ Des’‘mogen, = PRo- 
CAMBIUM ; ~ Lamel’la, of a spore, 
is the outermost layer of its coats, 
representing the original wall; 
~ Leaves, the primordial leaves ; 
~ Lay’er, see ‘‘tapetal cell” (infra) ; 
~ Mem’brane, the first (?) cell-wall ; 
~ Mem’bers, the primary shoot 
and root ; ~ Mer’istem, the embry- 
onic tissue of a young organ; ~ 
Pet’iole, the main rhachis of a com- 
pound leaf ; ~ Phlo‘em = ~ Bast; 
~ Root, the main root developed 
from the radicle ; ~ Shoot, the main 
stem developed from the plumule ; 
~ Struc’ture, a nascent organ, as of 
root or shoot; ~ tape’tal Cell, or 
Lay’er, the source whence the tape- 
tum is formed by bipartition of a 
cell or layer of periblem ; the other 
part of the division becoming the 
archesporium ; ~ Tis’sue, (a) that 
first formed or (b) formed during 
the first season’s growth ; ~ Wood, 
the wood developed by the pro- 
cambium. 
primigen‘ius (Lat., first produced) = 
PRIMITIVUS. 
Pri’mine, Pri’mina (primus, first), the 
outer integument of an ovule. 
prim’itive, primiti'vus (Lat., first 
of its kind), applied to the part 
first developed; specific types, 
in contrast to varieties and hy- 
brids ; ~ Wall, a boundary between 
the ooplasm and periplasm of the 
oosphere in Cystopus Bliti, De 
Bary (Stevens). 
208 
Primor’dia, pl. of Primor’dium (Lat., 
the beginning), a member or organ 
in its earliest condition ; the Ger- 
man ‘ Anlage”; primor’dial, pri- 
mordia’lis, first in order of appear- 
ance; ~ Cell, a naked cell, one 
without acell-wall ; ~ Epider’mis, 
the epidermis when first formed ; 
~Leaf, an intermediate form be- 
tween the cotyledon and those of 
the adult plant produced by growth 
from the plumule ; ~ Tis’sue, 
ground tissue ; ~ U’tricle, the outer 
layer of cell-protoplasm lining the 
inner surface of a vacuolated cell ; 
by some considered the same ag 
Ecroriasm. 
Pri‘mospore (primus, first, o7opa, a 
seed), term proposed by C. Mac- 
millan for those cases in which the 
spore is but little differentiated 
from an ordinary cell of the parent 
organism. 
prismat’ic, prismat’icus (Lat., like a 
prism), prism-shaped, with flat faces 
separated by angles; Prismench’- 
yma (éyxvua, an infusion), pris- 
matic cellular tissue. 
Pris’on-Flow’ers, those which imprison 
their insect-visitors until fertiliza- 
tion is effected. 
Proan’giosperms (pro, for, + Angios- 
perm), an Angiosperm in the act of 
becoming so from some ancestral 
form (Saporta and Marion); Pro- 
angiosper my, the state in question. 
Proanthe’sis (mp, early, dv@nots, 
flowering), flowering in advance of 
the normal period, as some flowers 
appearing in autumn in advance of 
the ensuing spring (Pax). 
Probas‘id (pro, for, + Bastp1um), Van 
Tieghem’s term for an organ inter- 
mediate between a basidium and a 
sporophore in Basidiomycetes, bear- 
ing a teleutospore. 
proboscid’eus (proboscis, a snout), 
having a large terminal horn, as 
the fruit of Martynia. 
Procam’bium (pro, for, + CAMBIUM), 
the embryonic tissue, consisting of 
somewhat elongated cells, from 
which the vascular tissue is eventu- 
