1906] CURRENT LITERATURE 369 
knowledge among the more primitive Archichlamydeae. The development 
of the floral parts and both lines of sporogenesis. were studied, the general con- 
clusion being reached that the characters agree with those of the majority of 
the primitive Archichlamydeae. In the ovule the sporogenous tissue develops 
as a mass of cells, from which usually a single mother-cell is selected, a late differ- 
entiation of that cell which is quite characteristic of gymnosperms. The linear 
tetrad is formed, ae there is the greatest irregularity in the selection of the func- 
tioning spore.—J. \ 
Embryo of Symplocarpus.—C. O. RosENDAHL‘? has made a preliminary 
announcement of a remarkable feature of the embryogeny of Symplocarpus- 
The endosperm destroys both integuments and pushes into the basal tissue of 
the ovule. There is a short, thick suspensor, and at this end of the ‘“ protocorm” 
both hypocotyl and plumule are differentiated. The developing embryo destroys 
the endosperm and all of the ovular tissue except at the very base, and thus comes 
to lie free in the ovary cavity! This means that the ‘“‘seeds” of Symplocarpus 
are naked embryos. The full paper, with illustrations, will be looked for with 
interest.—J. M. C 
Nucleoli in mitosis—The nucleoli in the vegetative cells of Equisetum 
arvense, according to G. BARGAGLI-PETRUCCI, play an important part in mitosis.3* 
In the resting nucleus there is a single centrally placed nucleolus. At the begin- 
ning of mitosis, the nucleolus divides, one of the daughter nucleoli passing to each 
pole of the nucleus, where it perforates the nuclear membrane and passes to the 
apex of the achromatic figure. 
While the figures are doubtless accurate, much more evidence will be required 
to establish the contention that the nucleoli play such a rdle in mitosis. —CHARLES 
Resistant potatoes.—The selection of races resistant to disease is one of the 
most promising methods of meeting many kinds of plant diseases. The resist- 
ance of Irish potatoes to blight, tuber rot, and scab has been worked out in an 
admirable way by StEwarT.3° More than one hundred and fifty varieties were 
tested and their difference in susceptibility is graphically represented. In general, 
varieties having strong, woody, moderately branched, upright stems, and medium 
sized, rather thick, firm, hairy leaves were more resistant than varieties possessing 
weak, much branched, decumbent stems with large, thin, smooth leaves.—F. L. 
STEVEN NS. 
37 ROSENDAHL, C. Oro, Preliminary note on the embryogeny of Sym plocar- 
pus foetidus Salisb. Science N. S. 23:590. 1906. 
8 BARGAGLI-Perrucct, G., I nucleoli durante la cariocinesi nelle cellule mer- 
istematiche di Equisetum arvense. Nuovo Giorn. Bot. Ital. 12: 699-708. pl. 
39 Stewart, W., Disease resistance of potatoes. Vermont Agr. Exp. Sta. Bull. 
122. 1906. 
