424 MISS М. BENSON —EMBRYOLOGY OF THE AMENTIFERZ. 
Carpinus Betulus. 
Fig. 48. Longitudinal section of nucellus (June 24th), showing area of sporogenous tissue shaded to 
represent the deeper-coloured granular appearance of this tissue. s., spindle-shaped cells ; 
p., pedicel; ¢., tapetum. 
Fig. 49. Longitudinal section of nucellus to show caecum of embryo-sac. t., tapetum. 
Fig. 50. Enlarged drawing from the preparation drawn in fig. 51. Тһе egg-cell appears to have been 
fertilized, and has already given rise to a 3-celled embryo. The pollen-tube is becoming 
disorganized, and in the portion abutting upon the embryo has evidently given up a portion of 
its contents, though actual perforation of its apex could not be demonstrated. em., embryo ; 
е.8., abortive embryo-sac ; f.e.s., fertile embryo-sac ; p.t., pollen-tube; $., suspensor. 
Рглте LXXII. 
Carpinus Betulus. 
Fig. 51. Nucellus showing the large fertile embryo-sac with three abortive embryo-sacs (a.e.s.) at its 
micropylar extremity. Throughout the greater length of the fertile embryo-sac (f-e.s.) is 
the pollen-tube ( p.7.), the apex of which abuts upon the small 3-celled embryo (em.). The 
chalaza is indicated by the letter c. 
Fig. 52. Diagrammatic longitudinal median section through ovary of Carpinus (equally for Corylus) to 
show course of pollen-tube. st., stylar cylinder; sc., sclerized tissue; pa., parenchyma ; 
pe., remains of perianth ; /., loculus; n., nucellus ; p.t., pollen-tube. 
Fig. 53. Longitudinal section of nucellus of Carpinus, dated July 1, showing four embryo-sacs. 
Fig. 54. Ditto, more truly median. Two embryo-sacs have thrown out czca towards base of nucellus, and 
one remains undeveloped in the apex of nucellus. Polar nuclei in the act of fusing shown 
in each cecum. e.s., embryo-sac. 
Fig. 55. Base of the nucellus (shown on a smaller scale in fig. 45 a). e.s.c., cecum of embryo-sac ; 
p.t., pollen-tube abutting on ditto. 
Fig. 56. The whole ovule on a smaller scale, from which fig. 45 was taken. 
Figs. 57, 58. Pollen-grains of Carpinus, germinated in 5 °/, sugar-solution, after 4 days. gr., pollen- 
grain; а., enlargement at apex of tube. 
Fig. 59. Upper part of ovary of Carpinus (July 1), showing the position of the (?) encysted pollen-tube. 
pa., parenchyma ; s., sclerized tissue ; p.e., encysted pollen-tube. 
Fig. 60. The encysted tube коне 840 онеш f.t., (?) remains of tube which was first formed 
from the germinating pollen-tube ; s.w., swollen wall after treatment with H550,; /., lumen ; 
t., (?) tube about to pass down to funicle. 
Juglans regia. 
Fig. 61. Longitudinal median section of nucelfus of Juglans, showing the archesporialtissue. а.с., central 
row of archesporial cells ; /.a., lateral row of ditto ; ¢., tapetum ; e., epidermis. 
