﻿iqi6] CHAMBERLAIN— STAXGERIA PA R. I IX.) X A 359 



grains are dry and powdery, but are still confined by the thin mem- 

 brane, which often holds them together even after they fall out 

 from the sporangium. Most of the pollen, however, is in condition 

 for wind pollination. Staminate cones of cycads are very frequently 

 infested by insects, both before and after the pollen has been shed, 

 but I have never seen anything to indicate that pollination was 

 being affected by their agency. Besides, the ovules exude a large 

 pollination drop, as in the case of gymnosperms known to be wind- 

 pollinated. 



When I reached Zululand, about the middle of January, 1912, 

 the pollen tubes had already discharged; in fact, embryos were 

 beginning to show suspensors. Although the season is somewhat 

 later farther south, I did not find any cones in which the pollen 

 tubes had not discharged. Accordingly, I am under great obli- 

 gation to other people for material of pollen tube structures. 



On January 6, 19 10, Professor W. C. Worsdell, whose exten- 

 sive researches have so materially advanced our knowledge of the 

 anatomy of cycads, visited Zululand and fixed for me some material 

 showing pollen tubes with the sperms already formed. Mr. W. T. 

 Saxton, formerly of the South African College, but now of the 

 Institute of Science at Ahmedabad, India, made several collections 

 in the Transkei, and arranged with Miss Sarah Van Rooyen, of 

 Kentani in the Transkei, for a close series of stages. The carefully 

 prepared material furnished by Miss Van Rooyen yielded an 

 excellent series of stages from the body cell, through the develop- 

 ment of the sperm, and up to early suspensor stages in the embryo. 

 The collections also included ripe seeds with mature embryos. 

 Seedlings have been grown both from Professor Worsdell's and 

 from Miss Van Rooyen's collections. 



The date of pollination was not determined definitely, but 

 material collected in the Transkei on July 17, 1907, showed uninu- 

 cleate pollen grains with exine and intine well developed. This 

 would indicate that pollen is shed late in July. Plants from that 

 region, now growing in our greenhouse, shed the pollen in January 

 19 16. The sporophylls of an ovulate cone loosened at the same 

 time, just as they do normally at the pollination period. This 

 wide difference is due doubtless to greenhouse conditions and not 



