226 BOOKS AND CURRENT LITERATURE 



America, has recently been announced.^ The prothalha were growing 

 in the vicinity of Marquette, Michigan, in sandy soil, and seventeen 

 of them were found on an area 10 meters square. In all five species 

 are represented: L. complanatum, L. annotinwm, L. clavatum, L. 

 obscurum and L. lucidulum, with twenty-one prothallia and fifty 

 sporelings. Prothallia of the last two species listed are new. The fact 

 that the discovery was made by a correspondence student of botany 

 makes it a unique one. Heretofore material for the study of prothallia 

 of Lycopodium has been obtainable practically only from Bruchmann 

 of Germany, whose studies are well known. 



In the same journal Chamberlain describes prothallia and sporelings 

 of three New Zealand species of Lycopodium: L. laterale, L. volubile 

 and L. scariosum} The prothallium of the first mentioned species 

 is green and leafy, and the protocorm-protophyll stage is present in 

 the development of the embryo; those of the last two species are sub- 

 terranean and lack the protocorm stage in their embryogeny. The 

 paper contains, in addition to descriptions of the prothallia and anatomi- 

 cal study of the sporophyte, a concise historical resume of the work 

 that has been done on prothallia of Lycopodium. — J. G. Brown. 



Recent Work on the Gnetales. — The Gnetales have recently 

 become adequately known, thanks to the supply of material which 

 is now available. Following the work of Land on Ephedra in 1904 

 and 1907, Lignier, Pearson and Thompson have cleared' up the chief 

 features in the morphology of the other two genera of the order. 

 Thompson's papers on Ephedra and Gnetum? bring anatomical data to 

 bear on the vexed problem of the relationships of the order, and this 

 author comes to the conclusion that "The angiosperms have been 

 derived from ancestors very much like modern Gnetales. In fact the 

 genus Gnetum should probably be classed with angiosperms." — M. A. 

 Chrysler. 



1 Spessard, E. A. Prothallia of Lycopodium in America. Bot. Gaz. 63: 66-76. 

 1917. 



2 Chamberlain, C. J. Prothallia and Sporelings of Three New Zealand Species 

 of Lycopodium. Bot. Gaz. 63: 51-65. 1917. 



3 Thompson, W. P. Anatomy and Relationships of the Gnetales. I. Ephedra. 

 Annals of Bot. 26: 1077-1104, pis. 94-97. 1912. 



Ibid. The Morphology and Affinities of Gnetum. Amer. Jour. Bot. 4: 135- 

 184. 1916. 



