156 NOTICES OF BOOKS. 
‘thinking that only Ferns and Rhizocarpee are derived Srey. from 
Marchantia, and Selaginella and Phanerogams from Jungermann : _ 
Rerropuction or ULoTHRIX ZONAT 
yo zonata, thre geschlechtliche und ngusahlsehiliohe Fortpflansung 
nm Bei zur Kenniniss der untern Grenzxe des pflanzlichen 
aiatichens, Von Dr. Annotp Dopet. (Pringsheim’s Jahrbucher 
fir Wissenschaft Botanik, vol. x., pp. 417-550, tab. xxxi-xxxvili.) 
Ulothrixz zonata has spores of two kinds—viz., 4-ciliated macro- 
zoospores produced either singly or fa together i in the mother-cell, 
aud 2-ciliated microzoospores arising several together in each mother- 
meti 
of a thread, but they usually have — 3 siete of activity, autumn 
r bein & favoutalia to ihe formation of macrozoospores, and 
on: er at o satel The latter copulate 
sp 
and form resting z= oospores, a fact which sets Areschoug’s* position 
beyond cavil; but the strangest thing of all is that those individuals 
which fail to copulate are like the yor zoospores in having the 
power of immediate asexual reproduction. This most Faiacksble 
observation, which its geremali. regards as furnishing a transition- 
state between sexual and asexual generation, comes to some extent to 
the timely support of the Strassburg school, who ag eh the fact 
of germination is sufficient proof of the asexuality of spermatia. 
Several figures are given showing polymorphism of the ‘iets and 
of the zoospores; between the two forms of the latter there are all 
kinds of transition, the only absolute distinction being based on the 
number of cilia. Further, it has long been known that microzoospores 
sometimes germinate while still in the othr obft and Dr. Dodel has 
seen some of them degenerate in this position without budding. Dr. 
Dodel agrees with Pringsheim that copulation of microzoospores is the 
morphological type of sexual reproduc see As for the zygozoospore, 
which, germinating after its period of rest, produces, not a thread of 
cells but a variable number of zoospores from which the threads arise, 
it is regarded as an independent new sexual a ore so that we 
have in Ulothriz true alternation of generation. Dr. Dodel points out 
asexual cell may become endowed with sexual sake es. 
Devetormenr or rue Frowerr or BrucMANsta AND ARTSTOLOCHIA. 
Die oe der Bliithe bet ee Zi pent ms _ Aristolochia 
Von H. zu Sotms-LavBa (‘ Botan- 
hae Zeitung,” July and sisiainals 1876. ) 
Tus is another of Count Solms’ contributions to the life-history of 
* “‘Observationes Phycologice. Particula secunda de Urospora mirabilé 
Aresh. et de chlorozoosporarum copulatione” Me ee 1874), arr “de nes, 
i Enteromorphe compressa,” Bot. Notiser, 1876. 
