140 THE JOURNAL OF BOTANY 
consideration ; the characteristic form of the igs cells ; oem 
conditions of reproduction and propagation ; the presence or abse 
of zoospore formation or of stolons; the fo orm of tha spn i als 
and of the spora nina” These points do ot all show 2 same 
degree of stability, but can be regarded as possessing more or less 
worth as diagnostic eae Relative inet of the salle i is 
denounced as quite worthless in this respect, and much of the 
present confusion in “the of getius eer from its use by the older 
writers. The creation of a new term “ evection”’ is to be regretted, 
and indeed it asetey ee be almost unnecessary. It is intended to 
the mann which the 8 
na part of the cell i . ‘su main pr and the consequent alteration 
n the angle of that cell wall. The author regards the varieties of 
ereution t in Cladophora as of importance from a systematic point of 
vie The result of this sigs of the genus from a broad stand- 
point is of such assistance towards understanding the few species 
which inhabit South Bavaria, “that it is to be hoped the author will 
if not the entire genus. Such is the confusion, however, reigning in 
Cladophora that an extra lease of life might be necessary for the task. 
‘‘Ueber Caulerpa: Ein Beitrag zur Biologie der Meeres-Or- 
ganismen,”’ by Prof. Reinke (Wissensch. Meeresuntersuch. Kommission 
Kiel neue Folge, Bd. 5, Heft 1, 25 Nov. 1899), is a somewhat 
speculative but interesting treatise from the biological point of 
view. In the introduction the author discusses the views of 
a egrets ong th 
atlo 
Reinke divides his paper into four sections. 1. A 
comparative review of the species of Caulerpa. 2. The question of 
the grouping of the species. 8. The morphological structure of 
Caulerpa, 4. Factors governing the external form 
n the first section, descriptions are given of thirty- seven of the 
fifty existing species, accompanied by new and excellent drawings, 
both natural size and magnified. In the main the same lines are 
the groundwork of all systematic study of this genus. The second 
section, which deals with the pire of the various species, is 
full of interest. The author starts with the premise that Caulerpa 
and other allied genera possess a common ancestor which first gave 
rise to such forms as Caulerpa fastigiata, Bryopsis duplex, and 
Derbesia, As he justly observes, such a premise can neither be 
eg nor refuted, and is at least useful as forming a starting 
point for the division of the genus ‘ahs natural groups. For a 
phylogenetic study of plants or animals three sources of information 
have to be taken into account—namely, paleontology, ogni 
distribution, and comparative morphology. In the case of Caulerpa, 
