520 BOTANICAL GAZETTE [june 



31. Schumann, K., Uber die weiblichen Bluten der Coniferen. Abh. Bot. 

 Ver. Prov. Brandenburg 44:1902. 



32. Scott, D. H., Studies in fossil botany. 2d ed. London. 1909. 



33. Sinnott, E. W., The morphology of the reproductive structures in the 

 Podocarpineae. Ann. Botany 27:39-82. pis. 5-Q. 1913. 



34. Sperk, G., Die Lehre von der Gymnospermie in Pflanzenreich. Mem. 

 Acad. Imper. Sci. St. Petersburg. VII 13: no. 3. 1869. 



35. Strasburger, E., Die Coniferen und die Gnetaceen. 1872. 



36. , Die Angiospermen und die Gymnospermen. 1879. 



37. Van Tieghem, Ph., Anatomie comparee de la fleur femelle et du fruit des 

 Cycadees, des Coniferes, et des Gnetacees. Ann. Sci. Nat. Bot. V 10: 269- 

 304. pis. 13-16. 1869. 



38. Worsdell, W. C., Observations on the vascular system of the female 

 "flowers" of Coniferae. Ann. Botany 13:527-548. pi. 32. 1899. 



39. , The structure of the female "flower" in Coniferae; a historical 



study. Ann. Botany 14:39-83. 1900. 



EXPLANATION OF PLATE XXIII 



All figures were made with a camera lucida excepting figs. 2, 4, 8, 10, and 

 part of 43. Text figures have been reduced to one-third and plate figures to 

 one-half original size. The scale of magnification of the figures is shown in 

 connection with the descriptions. 



Fig. 61. — Archesporial initial showing hypodermal position; X475- 



Fig. 62. — Two archesporial cells divided, each forming primary wall cell 

 and primary sporogenous cell; X475. 



Fig. 63. — Primary wall cells divided and beginning formation of mega- 

 sporangium wall; X475. 



Fig. 64. — Older nucellus showing several-layered wall and central mass of 

 sporogenous tissue (detail of fig. 39); X475- 



Fig. 65. — Portion of nucellus showing several-layered epidermis (cells 

 without nuclei), megasporangium wall (cells with nuclei), and sporogenous 

 tissue (shaded) with group of megaspores; X475- 



Fig. 66. — Portion of integument showing beginning formation of plug 

 tissue; X210. 



Fig. 67. — Mature plug tissue; X210. 



Fig. 68. — Detail showing integumentary regions, outer papillate epidermis 

 with heavy cuticle, hypoderm of large cells, sub-hypodermal layer, and 

 internal tissue; inner epidermis not shown; X210. 



Fig. 69. — "Stony cells" from hard integument showing protoplasmic 

 connections; X210. 



