1908]. CURRENT LITERATURE 75 
Cytology of the ascocarp.—According to FRASER,3° Hwumaria rutilans (Peziza 
rutilans) shows some interesting features in the origin and development of the 
ascus. The ascocarp originates as a tangle of hyphae without any differentiated 
sex organs, but nuclei fuse in pairs and the cells containing the fusion nuclei form 
ascogenous hyphae. Nuclear divisions in the hyphae show sixteen chromosomes, 
as do also the first and second divisions in the ascus. These two divisions have 
the characters of the heterotype and homotype mitoses. The third division in 
the ascus has eight chromosomes. During the first mitosis in the ascus the two 
nuclei of the ascus fuse. The spores are delimited by radiations passing from 
the centrosome, but near the base of the spore vacuoles may take part in the 
process.—CHARLES J. CHAMBERLAIN. 
Fossil cycadophytes.— WIELAND37 has published a short preliminary account 
of his examination of some of the most famous specimens of the Mesozoic cycado- 
phytes preserved in European collections. The specimens described are those of 
ycadeoidea etrusca, C. Reichenbachiana, Williamsonia gigas, and Anomozamites 
minor. With his long training in the American forms, the author was able to 
detect features which had escaped previous notice, confirming his results as to the 
bisporangiate strobilus, the synangial microsporangia, the branching habit, etc. 
Of special interest are Williamsonia, which links up the Mesozoic with the modern 
cycadophytes, and Anomozamites, with its slender branching stem, small blade- 
like leaves, and small strobili, which is more suggestive of the dicotyledons than 
any known cycadophyte.—J. M. C. 
Plant remains in Scottish peat bogs.—In continuing his studies of the Scot- 
tish peat bogs, Lewis3® has published the results of his investigations in the 
Scottish Highlands and in the Shetland Islands. Most interesting details: are 
given in reference to the different zones, and the author summarizes the situation 
in the following statement: “All the Scottish peat mosses [bogs] show a definite 
Succession of plant remains. The oldest, in the south of Scotland and the Shet- 
land Islands, have an arctic plant bed at the base. This is succeeded by a forest 
of birch, hazel, and alder containing the temperate plants. A second arctic plant 
occurs above the ‘lower forest,’ and is overlaid in all districts (except the 
Hebrides and the Shetland Islands) by an ‘upper forest’ covered by several 
feet of peat bog plants.”—J. M. C. 
Blepharoplast and centrosome of Marchantia.—Escovez*® has studied 
Mitoses in the spermatogenous tissue of Marchantia polymorpha and Fegatella 
ee 
3° FRaser, H. C, I., Contributions to the cytology of Humaria rutilans, Annals 
of Botany 22:35-55. pls. 4, 5. 1908. 
* WIELAND, G. R., Historic fossil cycads. Am. Jour. Sci. IV. 25:93-101. 1908. 
38 Le 
The Scot 
a 8° Escoyez, Evp., Blépharoplaste et centrosome dans le Marchantia polymorpha. 
Cellule 24:247-256. pl. I. 1907. : 
