82 BOTANICAL GAZETTE [JANUARY 
Spore formation among the Fungi imperfecti.—LEININGER™ studying 
the factors affecting the reproduction of Pestalozzia Palmarum, finds that this 
fungus has four modes of spore formation, whose manifestation depends upon 
the conditions under which the fungus is growing. Spore formation can always 
be induced by withdrawal of nutriment; the mode of spore formation, however, 
depends largely on the nature of the medium in which the fungus is growing 
or has been grown previous to spore formation. On submersed mycelia or 
on mycelia which are submersed after having grown on other media, true 
pycnidia are formed. Mycelia which have grown in liquid media also produce 
pycnidia when placed in a damp atmosphere. Mycelia growing in air on the 
surface of liquids, or on solid substrata, produce pseudopycnidia, i.e., fruiting 
organs with a pseudo-parenchymatous base, but whose upper part is composed 
of a thin layer of interwoven hyphae. Sori, which are never covered, and soli- 
tary spores are produced only on liquid media. Some organic substances 
seem to favor the production of one or the other of the last two modes of 
reproduction. The author suggests that the polymorphism of such forms ne- 
cessitates a reform in the classification of the Fungi imperfecti on a physiological 
basis. 
Another paper dealing with the instability of definite modes of reproduction 
among the Fungi imperfecti is that by Voces," who makes the difference in 
the spore-producing structures of two forms of Hendersonia a basis for a dis- 
cussion of the validity of the characteristics used in the classification of this 
group. The two species discussed are H. piricola, a leaf-inhabiting form on the 
leaves of pear trees, and H. sarmentorum, which occurs on the dead stems of 
many plants. In H. piricola the spores are formed in the epidermal cells and 
become exposed by the breaking of the cuticle. They are borne in sori, there- 
fore, with no vestige of a perithecium. In H. sarmentorum, however, a well- 
developed perithecium is formed. These two forms, although related in other 
characteristics, would thus fall into entirely different orders of the Fungi imper- 
fecti, and therefore the author regards the presence or absence of the perithe- 
cium as a characteristic of subordinate importance. The form of the spores 
and the number of cells they contain he likewise regards as of minor importance. 
ch variations are known to occur very frequently among the Fungi 
imperfecti, particularly in cultures of the more complex forms. As the classi- 
fication of this group is one of convenience and does not involve a taxonomic 
problem in the phylogenetic sense, it would be an error to lay great stress on 
such deviations which occur under special conditions or in a few forms, and 
to subordinate to them such conspicuous characteristics as the presence of a 
perithecium, which on the whole serve well for the distinctions of large groups 
of forms as they occur in nature —H. HAssELBRING. 
™ LEININGER, H., Zur Morphologie und Physiologie der Fortpflanzung von 
pc asarniet Palmarum Cooke. Centralb. Bakt. II. 29:3-35. jigs. 15. Ig11 
ocrs, E., Ueber die Pilzgattung Hendersonia Berk. Bot. Zeit. 68: 87-100. 
figs. 10. 1910. 
