3990, BOTANICAL GAZETTE [NOVEMBER: 
21. Ricwarp, L. C., Analyse botanique des embryons endorhizes ou mono- 
seine et particulitrement de celui des Graminées. Annales Paris 
at. Hist. 1'7:223-251, 442-487. 1811 
a2. Sauer ETHEL, Evolution of the monocotyledons. Bot. GAZETTE 37: 
325-345. figs. 6. 1904. 
23. STRASBURGER, E., Ein Beitrag zur Kenntniss von Ceratophyllum submersum 
und philogenetische Erérterungen. Jahrb. Wiss. Bot. 3'7:477-526. 
pls. Q-II. 1902. 
24. SCHAFFNER, J. H., The embryo sac of Alisma hints Bot. GAZETTE 
21:123-132. pls. Q-I0. 
25. The life history of Sagittaria variabilis. Bot. GAZETTE 23: 252-273. 
pls. 20-26. 1897. 
26. Some morphological or of the Nymphaeaceae and Helobiae. 
Ohio Nat. 4:83-92. ls. 5-7. 
27. WieGAND, K. M., The ae cncon é the mig, sac in some monocoty- 
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28. York, H. H., The embryo sac and embryo of Nelumbo. Ohio Nat. 4:167- 
176. 1904. 
EXPLANATION OF PLATES XVI-XVIII. 
Figures of the same relative value are drawn with the same lenses: igs. 
1-7 with Zeiss no. 4 oc. and 74 obj.; figs. 12-16, 20-28, 30, 32, 36, and 4o with - 
no. 4 oc. and DD obj.; figs. 8-11, 17-19, 29, 31, 37-39 with no. 4 oc. and A 
we PLATE XVI 
Fic. 1. Archesporial cell of Brasenia purpurea. 
Fic, 2. Megaspores of Nymphaea advena (?). 
Fic. 2. Uninucleate embryo sac of N. advena (?). 
_ Fic. 4. Mature embryo sac of Castalia pubescens, showing entrance of pollen 
tube (pt). 
Fic. 5. Embryo sac of C. pubescens just after fertilization, showing fertilized 
egg =a remains of synergids (sym), and the endosperm nucleus 
G. 6. Embryo sac of Brasenia purpurea just after fertilization, showing 
egg oe aoe: (syn), endosperm nucleus (end mi); and starch in the antipodal 
end of : 
Fic. : Embryo sac of Cabomba piauhiensis, poowlie fertilized egg (0); the 
* two synergids (syn), the endosperm nucleus (end nu) after first division, and 
the remains of a second sac (e s). 
Fic. 8. Embryo sac of N. advena ( ?), showing two-celled embryo, the nucellar 
tube, and the two daughter cells of the endosperm nucleus (e) separated by 
a. wall; the tube is about three-fourths the length of the ovule. 
Fic. 9a. Embryo sac of C. pubescens, showing large pear-shaped embryo 
with region of modified endosperm (x), and = nucellar tube. . 
Fic. 9b. Cross-section of nucellar tube of 
