464 BOTANICAL GAZETTE [December 



cytoplasmic inclusions within the nucleus. The chromatin is the 

 fundamental nuclear substance. 



Discussion 



The ventral canal cell. — The general tendency among the Co- 

 niferales is toward the reduction of the ventral canal cell. In the 

 Abietineae a cell is cut off by a cell wall; in the Taxineae and 

 Cupressineae, as groups, a ventral nucleus is formed, but no cell 

 is organized; while in Torreya (15) there is no ventral cell, the 

 nucleus of the central cell becoming the egg nucleus. In Abies the 

 nucleus of the ventral canal cell functions as an egg. In Pinus 

 Laricio (3, p. 278), "while the ventral canal cell nucleus usually 

 disappears soon after it is formed, in some cases it persists, and its 

 nucleus becomes as large as that of the oosphere, passing through 

 a similar developmental history. New support is thus given to 

 the theory that the ventral canal cell is the homologue of the egg." 



Nichols (21) describes (fig. 90) "two nuclei resulting from the 

 division of the ventral canal cell nucleus" in Juniperus. The ven- 

 tral canal cell "is fairly persistent in Tsuga (20). When division 

 is complete, its nucleus is equal in size and similar in structure to 

 the nucleus of the egg, and for some time shows the same stages 

 of development." 



The most extreme development recorded is in the case of Thuja, 

 described by Land (14). "A number of the writer's preparations 

 of Thuja lead him to believe that both the ventral nucleus and the 

 egg, in the same archegonium, may be fertilized. In fig. 17 the 

 proembryo is well advanced, while the ventral nucleus has formed 

 a group of four cells. Another preparation shows eight cells with 

 indications that walls are soon to appear. The probability of such 

 a fertilization is strengthened by finding occasionally in the same 

 ovule embryos growing upward into the nucellus. as well as down- 

 ward into the endosperm" (p. 224). These facts and those already 

 described for Abies remove any doubt that the ventral canal cell 

 is potentially an egg. 



The cytoplasmic "mantle" about the egg nucleus is present in 

 most species of Coniferales. Nichols (21) describes it in Juniperus 

 as follows: "The mass of cytoplasm and starch derived from the 



