222 BOTANICAL GAZETTE [MARCH 
two spermatozoids by the division of the generative cell was also confirmed. 
Ikeno’s work was entirely upon fixed material, so that he was unable to fol- 
low the motion of the living spermatozoids as Hirase had done, but he is 
sure that the spermatozoids. reach the egg by swimming, as at the time of 
fertilization a large amount of water was observed between the cap cells of 
the nucellus and the necks of the archegonia. 
This discovery of a close association of ginkgo and the cycads is but con- 
firmatory of what has been long suspected, as the former is too exceptional 
among the conifers not to have attracted attention, and more than one 
morphologist has suggested that it was a small-leaved cycad, rather than an 
nomalous conifer. Such confirmation, however, while it would have been 
notable enough under ordinary circumstances, is far eclipsed in importance 
ay the discovery of the association of siphonogamic and zoidiogamic fertiliza- 
tion. One of the most important barriers between pteridophytes and sperma- 
tophytes is thus broken down, and the transition to siphonogamic fertiliza- 
tion brought out with almost diagrammatic clearness. The further interest- 
ing fact is noted that in these two forms the pollen tube does not reach the 
archegonium, and hence motile spermatozoids are necessary. The general 
primitive character of these forms must be remembered, so that it need 
not be expected that such a condition of fertilization will be found exten- 
sively present among the gymnosperms.—J. M. C. 
THE IMPORTANT OBSERVATIONS of Professor Harper on “ The Develop- 
ment of the perithecium in Spherotheca Castagnei” *5 have been supplemented 
‘and extended by his studies on the development of the perithecium of 
Erysiphe, which, together with further observations on Sphzerotheca and on 
Ascobolus, form the subject of his more recent and very interesting paper, 
“Ueber das Verhalten der Kerne bei der Fruchtentwickelung einiger Ascomy- 
ceten.”"** After giving a brief summary of the literature relating to the 
sexuality of the ascomycetes, the writer reviews and extends his previously 
es 
the corresponding phenomena observed in ELvysifhe communis. \n this 
genus, as in Spherotheca, the perithecium originates from two branchlets, 
derived from different hyphz, the one oogonial, the other antheridial, The 
_ tips of these branches ‘become mieiewe by septa to form ae a terminal 
cell, the si Nees eae 
7 a, eee i: onium). a 
x VWOtiy th tiie large x o 
As a result of the absorption of the saliceiedlngs walls an open  poomanniee 
sth is Exists ——F between scare two e089 through which the single nucleus _ 
tS. way int _ where it unites with the 
ea of the latter. Cs ee Tk ce ay. whi ma b Pei og ir then produces 
} 
15 eviction. a. Deatsch. ae Gesell. ed 
"6 Prings. Jahrb. {. wiss. Bot. 29 :655 
