1909] CURRENT LITERATURE 67 
sor Dr. HOLTERMANN, a docent in the botanical institute. The work does not 
profess to be a verbatim report of SCHWENDENER’S lectures (which he himself 
could not make ready for the press), but is an expression of his views, based upon 
his lectures, published works, and personal communications; and moreover, the 
book has had his revision. The contents must suffice to show the character of the 
work: The mechanical system; Theory of phyllotaxy; Ascent of sap; Stomata; 
Twining; Tension of cortex; Distortion of pith rays by excentric growth; Ap- 
paratus for gliding; Turgor movements; Hygroscopic curvatures and torsion. 
To have these topics treated clearly and tersely is extremely useful, and Dr. 
HOLTERMANN’S service will be appreciated. —C. R. B. 
Pflanzenfamilien.—With the exception of a supplement to the section on 
lichens, which is in preparation, this monumental work? has come to an end with 
Lieferung 235, concluding BROTHERUS’ exposition of the mosses. It has been in 
course of publication since 1887, the last part being issued in March, 1909. The 
high appreciation of botanists all over the world must be the reward of the dis- 
tinguished senior editor, ENGLER, whose great plan has been so successfully exe- 
cuted. To the publisher, WirHELM ENGELMANN, also, are due congratulations 
for his courage in undertaking so huge a work, whose commercial success must 
have been problematic at the outset, and for his efficiency in the details of = 
tion.—C. R. B. 
NOTES FOR STUDENTS 
The perithecium of Ascomycetes.—The whole of Vol. X of Le Botaniste is 
devoted to an elaborate paper by DANGEARD’® on the origin of the perithecium 
in the Ascomycetes. Pages 1-26 are devoted to a general discussion of the subject, 
while pp. 27-385 are given over to the description of the individual plants studied. 
The writer is committed thoroughly to a belief in the autonomous nature of the 
fungi as a group, and in the derivation of the higher forms from phycomycetous 
ancestors. He postulates at the outset that the ascus is an organ of the same 
nature throughout the group; that it had a common origin; and that the slight 
variations which appear are the results of adaptation. He is confronted with 
four diverse opinions regarding the nature of the ascus: (1) that it is a modified 
sporangium; (2) that it isa sporocarp or part of a sporocarp; (3) that itis a mother 
cell presenting special characters; and (4) that it is a sporogonium. Each one of 
these theories is then discussed. The first, which is that of BREFELD, regards 
the ascus asa sporangium in which the form has become fixed and the number of 
spores definite. This is held to be untenable, since it implies the complete absence 
9° ENGLER UND PRANTL, Die natiirlichen Pflanzenfamilien, etc. 234 und 235 
Lieferung. ee (Schluss), Hypnodendraceae. Nachtrage und Verbes- 
serungen. Von V. F. BrotHerus. Teil I. Abt. 3. pp. 1153-1246. Leipzig: Wil- 
helm Engelmann. 1909. - 3. 
‘° DANGEARD, P. A., L’origine du périthéce chez les Ascomycttes. Le Botaniste 
1021-385. pls. I-91. 1907. 
