282 BOTANICAL GAZETTE [october 



7 Coulter, John M. and Land, W. J. G., Gametophytes an<] 

 taxijolia. Box. Gazette 39:161-178. pis. A^ i-j. 1905. 



s Pearson, H. H. W., Some observations on Welwitschiu : 

 Phil. Trans. Roy. Soc. London B 188:265-304. ph. 18-22, 1906. 



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pound staminate strobilus outside the Gnetales is the short branch 

 of ToTTQya taxifolia,'^ which bears a simple staminate strobilus in 

 the axil of each leaf of the short branch. It is conceivable that by 

 shortening the internodes in such a branch, combined with a further 

 reduction of the sporophyll number, a compound strobilus will result; 

 it is at least suggestive of the way in which staminate and ovulate 

 compound strobili may have originated. 



The two integuments of the ovule of Ephedra, a character shared 

 with the Taxineae, may be regarded as a primitive condition, a con- . 

 dition even more primitive than in Taxineae, for the nucellus is free 

 for a considerable part of its length. Also the inner integument first 

 appears as two parts, and the outer as four, each distinct in origin. 

 The tendency in both gymnosperms and angiosperms seems to be 

 toward union of the two integuments into one. 



The male gametophyte of E. triftirca shows a primitive condition 

 in that it has retained two persistent prothallial cells, A comparison 

 with the other groups of gymnosperms shows that in Cycadales the 

 male gametophyte is less primitive in that it has retained only one 

 prothallial cell, with perhaps occasionally another very evanescent 

 one. Ginkgoales have one persistent and one evanescent prothallial 

 cell. In Conifcralcs the Taxaceae and the Pinaceae show all grades 

 in reduction of prothallial cells; Podocarpus Halliiy now being 

 studied in this laboratory by Mr. L. L. Burlingame, frequently 

 has as many as eight prothallial cells; Taxus and Torreya have none; ( 



Araucaria perhaps shows several prothallial cells; Pinus has two 

 evanescent prothallial cells; and the Cupressineae none at all. j 



According to Pearson,^ Tumboa has one prothallial cell. The 

 testimony as to the Gnetums is doubtful; apparently some of them 

 have one ephemeral prothallial cell and others none at all. E, tri- 

 jurcaj therefore, may be said to have retained a primitive character 

 of its male gametophyte longer than Cycadales and Ginkgo, and 

 longer than most Coniferales. ' It is possible that the number of 

 prothallial cells will be found to var}^ in other species of Ephedra; { 



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