aw 
1903] GAMETOPHYVTES AND EMBRYO OF TAXODIUM 135 
SoKOLowA, MLLE. C.,’90: Naissance de l’endosperme dans le sac embryon- 
naire de quelques Gymnospermes. Bull. Soc. Nat. Moscow. f/. 2 
18go. 
STRASBURGER, E., '72: Die Coniferen und die Gnetaceen. 1872. 
‘77: Die Befruchtung und Zelltheilung. Jenaisch. Zeitsch. 2: 435- 
536. pls. 27-75. 1877. 
‘79: Die Angiospermen und Se Gymnospermen. 1879. 
84: Neue Untersuchungen, etc., 1884. 
92: Ueber das Verhalten des sas und die Sue hain 
bei den Gymnospermen. Hist. Beitr. 4: 1-158. f/s. 7-3. 1 
‘oo : Ueber a as nent etc. Hist. Beitr. 6: ae 
WEBBER, H. J.,’97*: Peculiar structures occurring in the pollen tubes of 
Zamia. Bot. GAZ. 23: 453-459. p/. go. 1897. 
97”: The development of the antherozoids of Zamia. Bot. Gaz. 24: 
———— '97°: Notes on the fecundation of Zamia and the pollen tube appara- 
tus of Ginkgo. Bor. Gaz. 24: 225-235. p/. ro. 1897. 
EXPLANATION OF PLATES [-XI. 
The abreviations used are: s¢, stalk cell or stalk cell nucleus; g7, genera- 
tive cell; Az, pollen tube nucleus; ¢c, central cell of pollen tube; sc¢, scler- 
enchymatous cells; vc, ventral canal nucleus; e#, egg nucleus. 
PLATE I. 
Fic. 1. Median longitudinal section through young microsporangium ; 
primary archesporium evident as rows of cells. Xx 400 
Fig. 2. Microsporangium in October; tapetum ditheretinted. X 300. 
FiG. 3. Spindle of first division of microspore mother cell. X 800. 
Fic. 4. Anaphase of same, showing four limbs to chromosomes. X 800 
FiGs. 5—6. Chromosomes seen from poles as they approach them; eleven 
_ in fig. 17. X 800. 
Fig, 7. Spindle of second division; mother-cell walls not yet dissolved. 
X 800. 
Fie. 8. Microspore before first division; cell wall not shown. X 800. 
FiGs. 9-11. Successive stages in first division of microspore. X 800. 
Fig. 12. Pollen grain on tip of nucellus, exine split off. x 800 
Fig. 13. Pollen grain beginning to germinate, exine split off and genera- 
tive cell swelling out. x 800. 
Fic. 14. The same; young stage of ry X 500. 
Fig.15. Tube nucleus moving down. X 500 
Fig. 16. Different relative position of pentieatire cell and pollen tube 
than in above. X 500. 
Fig. 17. Indication of branching in pollen tube. X 500. 
Fic. 18. Generative cell just before commencing to divide. x 800. 
