ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
147 
Characese. 
Bulbils of the Characeae.* — Dr. K. Giesenhagen has studied the 
structure and mode of formation of the clusters of bulbils formed at the 
nodes of the roots of various species of Chara, especially G. stelligera, 
aspera , baltica , and fragifera. Their development is fully described in 
the case of C. aspera. The bulbils in this species occupy a somewhat 
intermediate position in structure between the truly unicellular bulbils 
of Lamprothamnus alopecuroides and Lychnothamnus macropogon, and the 
multicellular bulbils of Chara baltica , fragifera, and delicatula. The 
remarkable regularity and uniformity which characterises the structure 
of the Characeae in other points is not subject to any exception in the 
case of these organs. 
Rabenhorst’s Cryptogamic Flora of Germany (CharaceseXf — Dr. W. 
Migula’s exhaustive and admirable monograph of the Central European 
species of Characese is now completed. Besides a description of every 
species and of the very numerous forms of some of the species — all of 
the former and many of the latter being admirably figured — it contains 
a full account of the morphology and history of development of the 
family, an essay on the position of the Characese in the natural system, 
an account of their geographical distribution, and instructions as to their 
collection, examination, and determination. All the non-German Euro- 
pean species are also referred to. 
Algae. 
Klebs on Reproduction in Algse andFungi.J — In this most important 
work Dr. G. Klebs gives the results of many years’ observations on the 
relation between the sexual and non-sexual modes of propagation in 
certain Algse and Fungi. He finds that, as a general law, it is the ex- 
ternal conditions which determine the production by any species of 
zoospores on the one hand, or of gametes on the other hand. 
With Vaucheria , zoospores are always produced when filaments which 
have been kept moist for some days are soaked with water, or when they 
are removed from a dilute nutrient solution into pure water, or when 
cultures in water or in a very dilute nutrient solution are darkened. If 
the filaments are placed in a 2-4 p.c. solution of cane sugar in bright 
light, gametes are always produced. Similar results were obtained with 
Hydrodictyon and some other Algae. In Spirogyra parthenogenetic 
resting-spores can be produced by placing filaments with long conjuga- 
ting-tubes in a strong solution of sugar. With fungi ( [Eurotium , Mucor) 
the results are more complicated and less clear than with Algae. 
Under the name Botrydium granulatum the author asserts that two 
quite distinct organisms have been confounded. On one of these he 
founds the new genus Protosiphon, distinguished from Botrydium by its 
propagation by means of gametes and non-motile spores instead of by 
uniciliated zoospores. 
* Flora, lxxxii. (1896) pp. 381-433 (1 pi. and 25 figs.). 
t Vol. v. Die Characeen, Leipzig, 1897, 765 pp. and very numerous figs. Cf. this 
Journal, 1896, p. 212. 
X ‘ Die Bedingungen d. Fortpflanzung bei einigen Algen u. Pilzen,’ Jena, 1896, 
543 pp., 3 pis. and 15 figs. 
