432 BOTANICAL GAZETTE [DECEMBER 
frond as functioning as gametes, and as producing a somewhat 
filamentous stage from which the mature Laminaria was vege- 
tatively developed. A paper by Kix1iAn (5) the following year, 
in discussing the development and structure of Laminaria, agreed, 
so far as it went, with the statements of Drew. This decidedly 
unexpected phenomenon of the sexual fusion of what from their 
origin should be zoospores met with considerable doubt, however, 
and was attacked by WILLrIAmMs (37), who claimed that it was not 
the motile zoospores of Laminaria, but other organisms, which had 
been seen to fuse by Drew. The first of SAUVAGEAU’s papers on 
the life history of the Laminariaceae appeared as a series on Sacco- 
rhiza bulbosa (25, 26, 27). Here he showed that in the case of the 
female the germinating zoospores from the unilocular sporangia 
produce a one to few-celled filament. The cells of this filament 
enlarge and emit a non-motile egg, which seemed to be fertilized in 
situ at the aperture, where it developed into a young sporophyte. . 
The male plant is more complex, of five or six cells and slightly 
branched, with several more or less clustered antheridia. Germina- 
tion of the zoospores within the sorus in which they were formed 
was seen, and it was found that the sporelings were both male and 
female, demonstrating that the sporangia on one plant produced 
| both sorts. 
_ Following this study appeared one on two species of Laminaria, 
L. flexicaulis (L. digitata) and L. saccharina (28, 30). SAUVAGEAU ~ 
found that in germination the chromatophore of the spore divides 
(the zoospore on attaching itself rounds up and forms a firm wall), 
and one half passes into the germ tube as it elongates. The nucleus 
also divides, and one daughter nucleus with a chromatophore 
passes toward the inflated distal end of the tube, where it is cut off 
by a transverse wall. The nucleus which remains behind dis- 
organizes more or less rapidly, while the cell with the other nucleus 
develops the gametophyte. Some of the male filaments are short, 
but others are elongate and markedly branched, forming the anthe- 
ridia laterally on the branches toward the end. One sperm is 
formed in each antheridium, and the sperms are shed before the 
female gametophytes in the same culture reach maturity. The 
female gametophytes are from one to several cells in extent, all 
