314 BOTANICAL GAZETTE [OCTOBER 
The prothallium of Kaulfussia is said to be the largest among Marattiaceae, 
a very large one reaching 2.51.75°™; but the usual adult size is 1°™ or more 
in length and nearly as broad. An endophytic fungus is always present. The 
_ antheridia and archegonia, restricted to the ventral surface, are also of ususua 
size. CAMPBELL thinks that probably all the organs of the embryo of Marat- 
in Kaulfussia. As in other members of the family, the shoot pierces through the 
prothallium and emerges from the dorsal surface. 
The prothallia of Gleichenia are also of the “‘massive-midrib” type, more 
or less lobed, and with an endophytic fungus. The antheridia are restricted to 
the ventral surface in all species except G. Jaevigaia, in which they occur upon 
both surfaces. In the species examined they are larger and more complex than 
recorded in the species examined by RAUWENHOFF, the wall cells being much 
more numerous, several hundred sperm mother cells sometimes being p uced, 
and an opercular cell probably always being present. The archegonia are more 
numerous upon the flanks of the “midrib” than upon its middle region; the 
necks are very long; and the neck canal cell (except in G. polypodioides) usually 
divides into two cells. The embryo, so far as the material permitted comparison, 
resembles that of the Polypodiaceae. The characteristic protostelic condition 
was observed in sporelings, but it was not discovered whether it persists in the 
adult form in all species.—J. M.-C. 
Sexual reproduction in the rusts.—During the last three or four ye ge 
MAN and Curistman have described a process of. sexual reproduction in the 
rusts. Their accounts are not in entire agreement, and so the ground has = 
traversed by Oxive,"s with an unusual wealth of material. About forty speci® 
were examined, and the most favorable form for the study undertaken pee 
to be Triphragmium ulmariae (Schum.) Link, on Ulmaria rubra Hill, a — 
form similar to the species of Phragmidium studied by BLACKMAN and se 
MAN. The two fusing cells (‘« gametes’’), as well as their nuclei, were foun iv 
be approximately equal, but for reasons given in detail it is concluded that of 
differ. somewhat in time of development. The equality and sexual = 
both the fusing cells are statements opposed to those of BLACKMAN. es 
concluded that the sterile cell (at the tip) is not an abortive trichogyne, - 
a “buffer cell” of the gametophyte. Conjugation takes place through pe 
foration developed in the contact-walls. It may begin through @ Very © the 
conjugation pore (observed by BLACKMAN), but this is regarded oe eke 
inning of a larger perforation. In the study of the various vee = con- 
divisions it was discovered that they are all mitotic, each nucleus — fo with 
jugate divisions acting independently. These nuclear divisions, conduct it was 
the aid of centrosomes, are described in detail; and in Triphragmium pie 
ascertained that the chromosomes are probably eight in number. se 
——__. » «tone in the 
*3 OLIVE, Epcar W., Sexual cell fusions and vegetative nuclear division® 
- Tusts. Annals of Botany 22: 331-360. pl. 22.1908. | 
