54 Gibbs . — Notes on the Development and Structure of 
nucellus ; per. 1. peripheral layers of nucellus ; ap. nuc. apex of nucellus ; st. starch ; dis.. c. 
disorganized cells; i.i. inner integument; o.i. outer integument; mic. micropyle ; cha. chalaza. 
X 400. 
Fig. 7. Stellaria media. Ovule with embryo-sac showing polar nuclei fused into one definitive 
nucleus : d. n. definitive nucleus ; 0. i. 1 , 0. i . 2 layer 1 and layer 2 of outer integument; i. i. 1} i. i. 2 
layer 1 and layer 2 of inner integument ; other lettering as before. x 400. 
Fig. 8. Arenaria trinervia. Embryo-sac showing oosphere, definitive nucleus and synergidae : 
00s. oosphere ; d. n. definitive nucleus ; syn. synergidae. x 450. 
Fig. 9. Stellaria media. Oospore forming basal suspensor cell with haustorium. Definitive 
nucleus preparing to divide : oosp. oospore ; haus. haustorium ; d. n. definitive nucleus ; syn. 
synergid ; p. t. pollen-tube, x 1100. 
Fig. 10. Arenaria trinervia. First segmentation of oospore into two suspensor cells: b. sus. c. 
basal suspensor cell ; end. n. endosperm-nuclei, x 450. 
Fig. 11. Arenaria trinervia. Suspensor with three cells : b. sus. c. basal suspensor cell; end . n. 
endosperm-nuclei; syn. synergidae. x 450. 
Fig. 12. Arenaria trinervia. Longitudinal section through chalaza and nucellus, showing 
cuticularized basal cells connecting up with the chalaza and integuments : nuc. nucellus ; b. c. basal 
cells of nucellus; cha. chalaza; v. b. vascular bundle of funicle. x 400. 
Fig. 13. Stellaria aquatica. Apical cells of nucellus prolonged as papillae; ap. nuc. apical 
cells of nucellus ; nuc. nucellus ; p. t. pollen-tube ; b. sus. c. basal suspensor cell, x 400. 
Fig. 14. Stellaria media. Embryo-sac with embryo, showing aggregation of endosperm-nuclei 
at apical end (endosperm-nuclei on further side of embryo-sac shaded) : end. c. endosperm cap^ 
b. sus. c. basal suspensor cell ; emb. embryo, x 450. 
Fig. 15. Stellaria ?nedia. Next section in same series showing haustorium of basal suspensor 
cell protruding beyond embryo-sac : haus. haustorium ; b. sus. c. basal suspensor cell ; e. s. embryo* 
sac. x 450. 
Fig. 16. Cerastium glomeratum. Longitudinal section through ovule : Embryo-sac elongaL 
ing after fertilization: per. 1. periph e ral layers of nucellus; b. c, basal cells of nucellus; e. s. 
embryo-sac ; prm. perisperm ; ax. c. axile-cells. x no. 
Fig. 17. Sagina apetala. Longitudinal section of apex of ovule, showing persistent pollen-tube : 
p. t. pollen-tube; p. t. t. pollen-tube twist; other lettering as before. x 400. 
Fig. 18. Stellaria media. Longitudinal section of ovule with embryo, showing perisperm forma- 
tion in nucellus : prm. perisperm; emb. embryo ; sus. suspensor \ fun. funicle ; sus. suspensor; other 
lettering as before, x 400. 
Fig. 19. Stellaria media. Longitudinal section of ovule with heart-shaped embryo showing 
progressive perisperm formation in nucellus and reduction of peripheral layers : cots, cotyledons ; 
other lettering as before, x no. 
Fig. 20. Stellaria media. Longitudinal section of ovule, showing embryo with cotyledons and 
endosperm cap ; lettering as before. x 75. 
Fig. 21. Stellaria media. Apical portion of same section under higher magnification, showing 
root apex of embryo, free'-cell formation in endosperm cap and disorganizing suspensor ; also cells of 
layer 1, outer integument, enlarging as papillae: dis. sus. disorganized suspensor; other lettering 
as before, x no. 
PLATE VI. 
Fig. 22. Stellaria media. Longitudinal section of mature seed showing embryo, endosperm cap, 
one persistent peripheral layer and central perisperm mass of nucellus with cuticularized basal cells 
and air spaces above them : pi. plumule ; pc. s. procambial strand ; sec. pap. secondary papillae ; 
a. s. air spaces ; other lettering as before, x no. 
Fig. 22 a. Longitudinal section of the wall of a cell of layer 1 of the outer integument showing 
secondary papillae and wavy cuticle, after treatment with Eau de Javelle and I & HjSO* : sec. pap. 
secondary papillae ; cut. cuticle, x 450. 
Fig. 22 b. Surface view of wall treated in the same way; sec. pap. secondary papillae; cut. 
cuticle, x 450. 
Fig. 2 2 c. Longitudinal section of basal cells of nucellus, showing shallow pits in the : cuti- 
cularized walls : after treatment with Eau de Javelle and I & Ii 2 S 0 4 . x 450. 
