82 BOTANICAL GAZETTE [JULY 
Puccinia Peckiana. The wonder is that the true nature of this exceedingly 
common fungus has remained so long unknown. 
Although the cell rows forming the peridial wall in the aecidia of rusts 
are usually considered to be homologous with the spore chains, it is generally 
believed that the intercalary cells characteristic of the spore chains are not 
rusts belonging to different types, and finds that a complete homology exists 
between the spore chains and the cell rows of the peridium. The basal cells 
of the peridium give rise to a series of cells each of which divides, cutting o 
a small cell in the lower outer corner. These small cells, which correspond to 
the intercalary cells, thus lie toward the outside of the rows of cells forming 
the peridial wall. By the growth of the peridial cells they are crowded still 
farther outward. Their walls soon become gelatinous and their structure is 
entirely obliterated, so that they are not recognizable in any but the youngest 
parts of the aecidium. This fate undoubtedly accounts for their remaining 
long unobserved. The basal cells of the peridial rows, as well as the peridial 
cells themselves and the “‘intercalary”’ cells, are binucleate, like the basal cells 
of the spore chains, in all cases except in a form of Aecidium punctatum Pers. 
(Puccinia Pruni-spinosae Pers.), which had uninucleate basal cells, giving rise 
to uninucleate aecidiospores and peridial cells. This form resembles in this 
u was 
uninucleate cells discovered, has uninucleate basal cells also—H. HAssEL- 
BRING 
Resistance of mosses to drought and cold.—It has long been known that 
many mosses are able to survive long periods of extreme drought, although 
much of this knowledge has been based upon inexact and insufficient data. 
It is a matter of much satisfaction, therefore, to have their resistance proved 
by the exact and extensive results of InmscHER* based upon careful experi- 
ments with a large range of species. He finds resistance to drying related in 
a remarkable degree to the ordinary habitat of the species, but often sur- 
prisingly great even for aquatic and mesophytic forms. Thus, while the 
leaves of some species of Fontinalis succumbed to a week’s air-drying or to five 
days in a desiccator, Philonotis fontana and three species of Hypnum died only 
after 15-20 weeks in dry air or 10-18 weeks in the desiccator. The mesophytic 
species from deciduous forests, like Barbula subulata, Bryum alpinum, Mnium 
2 Kurssanow, L., Uber die Peridienentwicklung im Aecidium. Ber. Deutsch. 
Bot. Gesells. 32:317-327. pl. 1. 1914. 
2 MorEav, Mrs. F., Sur ]’existence d’une forme écidienne uninucléeé. Bull. Soc. 
Mycol. France 27:489-492. fig. I. 1911 
Irmscuer, E., Uber die resistenz der Laubmoose gegen Austrocknung und 
Kalt. Jahrb. Wiss. Bot. 50:387-449. 1912. 
