380 BOTANICAL GAZETTE [way 
SEVERAL RECENT INVESTIGATIONS have brought to light a curious condition 
in certain plankton diatoms which is believed to be a method of spore formation. 
The contents of certain cells break up into a number of small bodies which are 
termed “‘microspores.”” These structures have been recently investigated by 
STEN?? in a species of Corethron. Their development begins in this form 
with a remarkable increase in the number of nuclei in a single diatom, until as 
many as 128 are present. The nuclei divide mitotically and the protoplasm succes- 
sively until this large number of bodies are found, which however often remain con- 
nected with one another by delicate fibrils of protoplasm. KarsTEN believes that 
“microspores” which escape from the mother diatom are gametes and unite with 
one another in pairs to form a zygospore. Further, there is evidence that the 
zygospore gives rise to two new diatoms and that each of these contains at first 
two nuclei, one of which afterwards breaks down. If this should be established, 
we should have presented in the diatoms a method of sexual reproduction followed 
by a type of germination with two successive mitoses apparently of the same 
character as in the desmids. It is fair to say, however, that KARSTEN seems to 
draw his conclusions from a rather imperfect series of stages.—B. M. DAvIs. ° 
PELETRIsoT’? has published an extended study of the development of the 
seeds of Ericaceae, including in his examination twenty-six genera and sixty-two 
species. Such a survey can only mean a glimpse of a general situation, which 
subsequent research will develop properly. Aside from anatomical details of 
tissues, which can hardly be related as yet, the general morphological situation 
seems to be about as follows. The most striking feature of the embryo sac is 
the development of a large haustorial pouch at each end. This haustorium varies 
much in size in different genera, reaching its maximum in Arbutus; and also in 
its degree of separation from the central cavity, sometimes being separated only 
by a slight constriction, and in other cases by a narrow, more or less prolonged 
neck. In many of the genera there is also a well-developed jacket-layer investing 
the central cavity of the sac. The synergids are often beaked and extended into 
the micropyle, and the antipodals are ephemeral. 
ide from the extent of the survey and the prolix presentation, the most 
notable feature of the paper is the absence of all knowledge of any English or 
erican publications dealing with similar haustorial developments.—J. M. C 
THE PosITION of the monocotyledons is discussed in a recent paper by 
Fritscu.3t Since the geological history is so fragmentary, we must rely upon 
the evidence of comparative morphology. After discussing this evidence, 
29 KarstTEN, G., Die sogenannten “Mikrosporen” der Plankton-Diatomeen und 
ihre weitere Entwickelung beobachtet an Corethron Valdiviae. Ber. Deutsch. Bot- 
Gesells. 22:544-554. pl. 23. 1904. Ewe 
3° PELETRIsOT, C.-N., Développement et structure de la graine chez les Ericacees- 
Jour. Botanique 18: 309-367, 386-402. figs. 173. 1904- 
3* FritscH, K., Die Stellung der Monokotylen im Pflanzensystem. 
Bot. Jahrb. Beiblatt No. 79. pp. 22-40. 1905. 
Engler’s 
. 
