12 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
of Stangeria paradoxa. The spermatozoids in this instance have not 
yet been studied in the living state and the details of the spermato- 
genesis have not yet been followed. 
In the report of a paper read before the American Society for Plant 
Morphology and Physiology, published in Science, February 15, 1901, 
the writer (128) described the cell division giving rise to the stalk 
cell and central cell, and the morphology of the prothallial apparatus 
which has been entirely misinterpreted in all previous descriptions. 
The description there given is the same as that published in this 
monograph. 
ACKNOWLEDGMENTS. 
In concluding the introduction, the writer desires to express his 
indebtedness to various friends for aid furnished in the course of this 
investigation: To Dr. William Trelease, director of the Missouri 
Botanical Garden, who kindly aided him by furnishing developing 
seeds of Ginkgo biloba collected at regular intervals, and by general 
advice; to Mrs. L. H. Webber for considerable aid in the prepara- 
tion of drawings; to Prof. E. C. Jaffrey and Dr. Erwin F. Smith for 
aid in the preparation of phetomicrographs; and to Sir William 
Dyer, Prof. B. L. Robinson, and Mr. F. V. Coville for the privilege 
of examining and studying the species of Zama in the Kew, Gray, 
and U.S. National herbaria, respectively. Lastly thanks are due to 
my colleague, Mr. Walter T. Swingle, who has aided me greatly 
throughout this investigation. Whatever merit the study may possess 
is, in a laree measure, due to him. 
METHODS AND MATERIALS USED. 
The investigations have been limited mainly to the species of Zamia 
growing wild in Florida. Ginkgo was studied somewhat for compari- 
son, but as this plant was being studied by Dr. Hirase, little time was 
given to its Investigation. When the writer began the investigation 
of Zamia the forms growing in Florida were all generally referred to 
Lamia integrifolia Jacq. In the course of the investigations it was 
found that there were at least two distinct species in the State, neither 
of which could be considered as belonging to Zama integrifolia Jaca., 
which is a West Indian species. One species is found very abundant 
on the east coast of Florida south of New River. This corresponded 
well with the description of Zama floridana D. C., and a comparison 
of a fragment of specimen and a tracing in the Kew Herbarium of 
De Candolle’s original specimen showed that the south Florida form 
must undoubtedly be referred to this species.’ It has large elliptical, 
1 Zamia floridana D.C. (Prodromus 16, p. 544.) Leaves ovate or ovate-lanceolate, 
20 to 30 cm. long, excluding the petiole; petiole about 20 cm. long, unarmed, trian- 
gular, sericeo-tomentose at base, with scattered hairs above; leaflets mostly opposite, 
