1895.] Botany. 929 
Mexico, Arizona and Mexico; P. versicolor microphylla from Mexico ; 
P. macrophysa, from Arkansas, Kansas, Texas, and doubtfully North 
Carolina and Ohio. 
The Mycetozoa.—These organisms which have generally been 
regarded as plants, and which are treated in the ordinary botanical 
works under the name of Slime Moulds have been recently studied 
more from a biological standpoint by Arthur Lister, the results of 
which have been brought out by the trustees of the British Museum in 
the form of a monograph of the group. The work is of such interest 
to students of this group that we quote the following selections from the 
introduction since they contain so much of general information re- 
garding these curious organisms. 
“Fries gave the name of Myxogastres in 1833, to the group of organ- 
isms described in this Monograph, placing it among the Gasteromycet- 
ous Fungi. In 1836 Wallroth substituted the term Myxomycetes 
(Schleimpilze) for the older name, and this came to be the generally 
accepted designation. Later investigations showed that the spores, 
instead of producing a mycelium, as in the case of fungi, gave birth to 
swarm-cells, which coalesce to form a plasmodium. In consequence of 
this discovery, which indicated a relationship with the lower forms of 
animal life, De Bary in 1858 introduced the name Mycetozoa. Under 
this head he still retained the term Myromycetes for the section so 
named by Wallroth, but linked with them the Acrasiee of Van Tieg- 
hem, a small group inhabiting the excrement of animals; in these the 
spores are said to produce swarm-cells, as in the Myxomycetes, which 
multiply by division but do no coalesce to form a plasmodium. At a 
certain period, when the fruits are about to be formed, they become 
attached in branching strings which concentrate to a point, where 
they are massed together in aggregations of more or less definite shape ; 
the swarm-cells, however, do not lose their individuality. In Dictyos- 
telium, a genus of the Acrasiee, a stalk is formed by the arrangement of 
a number of swarm-cells in vertical rows in the centre of the heap; 
the surrounding ameeboid bodies creep up this stalk and form a globose 
cluster at the extremity; here each ameboid swarm-cell acquires a 
spore-wall, and they become a naked aggregation of spores not enclosed 
by a definite sporangium-wall. Rostafinski followed De Bary in the 
1 A Monograph of the Mycetozoa, being a descriptive catalogue of the species in 
the Herbarium of the British Museum; illustrated with 78 plates and 51 wood- 
cuts by Arthur Lister, F. L. 8. London, 1894. 224pp. 8vo. 
