286 SUMMARY OF CURRENT RESEARCHES RELATING TO 



B. CRYPTOGAMIA. 



Cryptogamia Vascularia. 



Antheridia and Antherozoids of the Heterosporous Lycopodiaceae 

 (Selaginellaceae).* — Herr W. Belajeff lias made a detailed examina- 

 tion of the internal structure and germination of the microspores of 

 Isoetes and Selaginella, with a view to reconciling the conflicting 

 statements on some important points of Millardet and Pfeffer. While 

 differing on some points from both these authorities, he agrees much 

 more nearly with the former than with the latter. 



Of Isoetes the two species examined were I. setacea and Malinver- 

 niana, in both of which the microspores closely resemble those of 

 I. lacustris. The spores have three membranes, epispore, exospore, 

 and endospore : of which the innermost shows the cellulose reaction 

 with zinc chlor-iodide, but neither of the outer ones. The outermost 

 coat, the epispore, is yellowish, and has a fissure through which the 

 exospore projects. In I. setacea the epispore is very thick and full 

 of vacuoles. The brown exospore or middle coat is the first formed 

 of the three. In the interior are a number of albuminous granules 

 and a nucleus. 



The first process in germination is the separation of a small 

 lenticular cell, the rudimentary prothallium, the rest constituting the 

 antheridium. This then divides into three cells by two oblique 

 walls, and the central of these again divides into two. Each of these 

 four primary cells of the antheridium contains a nucleus ; their walls 

 do not show cellulose reaction. By further division the antheridium 

 consists of two internal cells completely surrounded by four outer 

 ones ; the two inner ones are hyaline, the four outer ones filled with 

 granular protoplasm. Each of the two inner cells again divides into 

 two ; these four all contain nuclei, and are the mother-cells of the 

 antherozoids. The surrounding cells coalesce, by the disappearance 

 of their walls, into a turbid granular mass. The lenticular pro- 

 thallium remains all this time unchanged. The membrane of the 

 inner cells finally deliquesces and the antherozoids uncoil, two disc- 

 shaped spongy bodies dropping from them at the same time. 



The antherozoids of I. Malinverniana are remarkably large. They 

 consist of a spirally coiled ribbon-shaped body and a large number of 

 cilia all attached to the anterior end ; all of them also coiled, and at 

 first pointing backwards. Attached to the body along its length is a 

 clear ribbon-shaped appendage, which is broadest behind. The anthero- 

 zoids are in motion only for from three to five minutes, and then 

 coil up to the form they had in the mother-cell. All the nuclein in 

 the nucleus of the mother-cells is used up in the construction of that 

 of the body of the antherozoids. The cilia are formed out of the 

 protoplasm of the mother-cell. 



In the microspores of Selaginella the author found two types of 

 structure, one represented by S. Eraussiana and Poulteri, the other by 

 S. cuspidata, Isetevirens, fulcrata, stolonifera, Martensii, viticulosa, 

 insequalifolia, and caulescens. 



* Bot. Ztg., xliii. (1885) pp. 793-802, 809-19 (1 pi.). 



