I 



1907] CALDWELL— MICROCYCAS CALOCOMA 139 



sporangia. II. The ovule of Stangeria paradoxa. Annals of Botany 14: 



281-306. pis, iy-i8. 1900. 



ULTER, J. M., and Chamberlain, C. T., The embryogeny of Zamia. 



6-8 



W 



Box. 



Gaz. 36:1-27^ 114-140. pis, i-ii, 1903. 



12. , Notes on the gametophytes and embryo of Podocarpus. Box. 



Gaz. 33:89-107. ph. 5-7. 1902. 



13. GoROSCHANKTNj J.^ Zur Kenntnis der Corpuscula bei den Gymnospcrmen. 



Bot. Zeit. 41:825-831. pi. 70. 1883. 



14. Treub, M., Recherches sur les Cycadees. 3. Embryogcnie du Cycas cir- 



cinalis. Ann. Jard 



15. Smith, M 



in Zamia. Box. Gaz, 37: 



fig^ 



16. Stores, M. C., and Fujii, K., The nutritive relation of the surrounding 



tissues of the archegonia in gymnosperms. Beih. Bot. Centralbl. 20: 1-24. 

 pi. J. 1906. 



EXPLANATION OF PLATES X-XIII 



PLATE X 



Fig. 15. Diagram of nucellus showing haustorial branches of pollen tubes 

 growing upward and outward from pollen chamber. X15. 



Fig. 16. Diagram of megasporophyll showing anastomosing of veins in 

 expanded portion; veins passing into ovule and rebranching at base of ovules 

 into outer fleshy and stony layers: g, female gametophyte; n, nucellus; i, stony 

 layer; v, unbranched vascular bundle in fleshy layer (0); v^, branching vascular 

 bundles in stony layer. Xf. 



Fig. 17. Pollen tube containing eight body cells, some of which show two 

 blepharoplasts; one small tube nucleus; stalk cell and projecting into it the 

 prothallial cell; a fragment of the exine adheres to the intine at the base of the 

 tube. X160. 



Fig. 18. Pollen tube with eight body cells, tube nucleus, stalk cell, and 

 prothallial cell. X160. 



^ at left of fig. ly; contains ten body cells and the other 



■ r 



h 



body cells. X 160 



PLATE XI 



Fig. 21. Body cell surrounded* by thin layer of cytoplasm; blepharoplasts at 

 opposite ends of the cell; nucleus apparently compressed by radiating fibers; 

 prominent nucleolus. X 750. 



Fig. 



4 



body cell. X 1400 



400 



