Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
29. 
30. 
81. 
32. 
98. 
. 99. 
. 86. 
PU 
g. 38. 
. 99. 
. 40. 
44. 
45 
. Longitudinal section of nucellus, cut June 21, 1892. 
. Upper part of similar section. p.e.s., position in which a second e 
. As before. This section shows four embryo-sacs. The elongation о 
EMBRYOLOGY OF THE AMENTIFERA. 423 
Longitudinal section of nucellus and part of inner integument of Quercus гет. т., micropyle ; 
қ А СИ 
e.s., embryo-sac ; a., antipodals; b.c., basal part of axile row; nu., nucellus; cæ., cecum of 
embryo-sac ; 4.2., inner integument. 
Betula alba. 
Longitudinal section of nucellus, Мау 16, 1892. а.с.с., archesporial central-cell dividing. 
Ditto a little more advanced. а., archesporium. 
Alnus glutinosa. 
Outline of upper part of long. sect. of ovary and one ovule just fertilized. p.t., pollen-tube ; 
e.s., embryo-sac ; c.a., central axis; lo., loculus. 
Embryo-sac of fig. 32 enlarged. p.t., pollen-tube; s., synergide ; e.c., egg-cell; f., fusing 
polar nuclei; а., antipodals. 
Prate LXX. 
Alnus glutinosa. 
As in fig. 32, but here is shown the pollen-tube entering the chalazal region, also a transverse 
section of the tube to the right above the level of embryo-sac. s., stylar rudiments; c., 
cellular tissue ; ch., sheath of crystals; p.t., pollen-tube ; e.s., embryo-sac. 
Transverse section of ovary taken at level of dotted line c.c. in fig. 34. p., loose parenchyma 
showing no stylar canal; ch., crystal sheath and lignfied tissue. 
Enlarged drawing of base of ovule of fig. 34. ch., chalazal region ; p.t., pollen-tube; i.r., 
integument (level of insertion of) on the side nearer the raphe; i.d., do. on the distal side; 
р., branch of pollen-tube. 
Embryo of Alnus, July 25, 1892. The embryo-sac has eaten its way to the epidermis of apex 
of nucellus. Three free transitory endosperm-cells are shown. 
Diagrammatic drawing of ovule of Alnus to show course of the pollen-tube (p.£.). е.з., embryo- 
sac; f., funicle; v.b., vascular bundle; m., the closed micropyle. 
Corylus Avellana. 
of Corylus before the ovule is ready for fertilization. 7., remnant 
Longitudinal section of ovary 
pa., loose parenchyma; V., vascular bundle now 
of stigmas; p., perianth ; ch., crystals ; 
become central; си., cupule. : 
Ditto much earlier, showing stylar canal open, and vascular bundles of placentæ still not 
approaching the centre. 0., ovule; 5.с., stylar canal; other letters as in fig. 39. , 
e.s., embryo-sae; t., tapetal region; 
ә pedicel. 
dd mbryo-sac lay ; a.c., central 
strand of archesporium ; r.ep., rudimentary epidermal cap. 
d ge f tapetal cells is often seen. 
p., pedicel; ep., epidermal sac; e.s., embryo-sac. 
Prate LXXI. 
Corylus Avellana. 
n of ovule showing pollen-tube ascending from chalaza. 
) n-tube. 
ә cecum of 
DLougitndinal sectio 222. 
embryo-sac; m., micropyle; p.t., polle 
Pollen-tube and adjacent cells in the previous fig. enlarged. 7). 
с.р., cells of nucellus. 
refringent granules, ?nucleus ; 
Figs. 46, 47. Pollen-tube abutting on cecum of embryo-sac. 
