1904] LAND—EPHEDRA TRIFURCA 17 
——., Die Angiospermen und die Gymnospermen. 1879. 
——, Neue Untersuchungen, etc. 1884. 
, Ueber das Verhalten des Pollens und die gee vorginge bei den 
Geancaneiee: Hist. Beitr. 4:1-158. pls. 1 
, Anlage des Embryosackes und Picasa bei der Eibe nebst 
ausschliessenden Erérterungen. Jena. 1904. 
Trevus, M., Recherches sur les Cycadées. Ann. Jard. Bot. Buitenzorg 2: 32-53- 
pls. 1-7. 1881 (date of reprint, volume date being 1885). 
Warminc, E., Recherches et remarques sur les Cycadées. Oversigter over d. 
K. D. Vidensk. Selsk. Forh. 1877. 
EXPLANATION OF PLATES I-V. 
All figures were drawn with an Abbé camera lucida, and reduced one- -half in 
reproduction. Abbreviations are: br, bract; a, primordium of stamen; 9, peri- 
anth; oi, outer integument; ii, inner integument; 7, nucellus; pc, pollen- -chamber; 
s, microsporangium; pw, primary wall-cells; w, wall-cells; ¢, tapetum; ar, arche- 
sporial cells; prt, first prothallial cell; pr?, second prothallial cell; a7, anther- 
idium initial; ¢n, tube nucleus; g, primary spermatogenous cell; sé, nucleus of 
stalk cell; bn, nucleus of body cell; mm, megaspore mother-cell; m, megaspores; 
_ mr, nutritive region of female gametophyte; hr, haustorial region of gametophyte; 
b, abortive archegonium; nc, neck cells; ¢, central cell; vv, ventral nucleus; 0, egg. 
1G. 1. A bisporangiate strobilus. x 16. 
Portion of a longi seme section through a staminate seeobiins 
showin ae and primordia of two anthers. X 225. 
1G. 3. Longitudinal section through an anther showing beginning of peri- 
anth a primordia of two sporangia. x 225. 
Fic. 4. Longitudinal section through a sporangium showing sporogenous 
cells, part of an adjoining sporangium, and perianth X 225. 
Fic. 5. Division of primary wall cells; the sporogenous cells are also actively 
dividing. x 500 
Fic. 6. Early stage of the microspore mother-cells. X 500. 
Fic. 7. Microspore mother-cells in resting stage. X 500. 
Fic. 8. Microspore mother-cell after segmentation of the sie x 1500. 
Fic. 9. Microspore mother-cell, heterotypic division. X 1 
Fic. to. Polar view > chromosomes in anaphase of Boat mitosis in micro- 
spore mother-cell. < 1 
IG. rr. Later stage see division of microspore mother-cell. X 1500. 
Fic. 12. Prophase of homotypic division. 1500. 
Fic. 13. Homotypic division. X 1500. 
Fic. 14. Tetrads and enlarged tapetal cells. 00. 
Fic. 15. A microspore shortly before the first Se x 1500 
Fic. 16. Microspore after formation of first prothallial Ce xT ten 
Fic. 17. Division to form second prothallial cell and antheridium initial. 
Fic. 18. First and second prothallial cells and antheridium initial. * 1500. 
