ISTichols, A morphological study of Juniperus communis var. depressa. 241 



Fig. 95. Entrance of two male cells frora one pollen tube into different 

 archegonia. X 306. 



Figs. 96 — 100. General appearance consugating male and female nuclei. 

 The cytoplasm and starch of the male cell are indicated by tbe dotted lines. 

 X 306. 



Plate XVII. 



Fertilization and the development of the proembryo. 



Fig. 102. Male nucleus and egg in contact and surrounded by mantle 

 of starch. X 640. 



Fig. 103. Fusion nucleus. More or less definite spirems have already 

 been organized. Partly reconstructed from two of the three sections into which 

 the nucleus was cut by the razor. X 640. 



Fig. 104. Fusion nucleus just before first segmentation division. Two 

 distinct spirems are present. X 640. 



Fig. 105. Late prophase in first division of fertilized egg. The chro- 

 mosomes are being oriented at a common equatorial plane. X 640. 



Fig. 106. Telophase of segmentation division. X 640. 



Fig. 107. Daughter nuclei of segmentation division. X 640. 



Fig. 108. Second free nuclear division of proembryo. X 392. 



Fig. 109. The four nuclei resulting from this division. X 392. 



Fig. 110. Third free nuclear division of proembryo. X 392. 



Fig. 111. An unusual instance where sixteen free nuclei are being de- 

 veloped before wall formation. X 306. 



Fig. 112. First nuclear division following formation of walls. X 306. 



Fig. 113. The same completed. X 306. 



Fig. 114. Proembryo after slight elongation of suspensors. X 160. 



Beihefte Bot, Centralbl. Bd. XXV. Abt. I. Heft 2. 16 



