490 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Ravenelia.* — Herr P. Dietel gives a monograph of this genus of 
Uredinese. The remarkable cysts or sterile cells, which are peculiar to 
the genus, appear to be a contrivance for detaching the parasite from 
its host. The author classifies the 27 species (some of them new) under 
5 sections, — Euravenelia, Baveneliopsis, Brachyravenelia, Hemiravenelia, 
and Microravenelia. 
Polysaccum.'j' — Dr. E. Bruns describes the structure and develop- 
ment of this genus of Gasteromycetes, especially of P. crassijpes. The 
so-called “root-portion” is often the most strongly developed, and this 
frequently forms a weft round fir-roots, constituting a kind of mycorhiza, 
which is, however, by no means essential for the nutrition of the pine- 
roots. 
Rhizobes.J — In the tubercles of Melilotus dibus Herr A. Schneider 
finds two species of Bhizobium, B. Frankii and mutabile. The latter is 
intimately associated with the cytoplasm of the cells, and is identical 
with the so-called bacteroids. The former is motile, and has usually 
two cilia, one at each end, sometimes only one ; the spores have often 
three or four cilia. It increases more rapidly than the bacteroids and 
effectually prevents their multiplication. By its movements it incites 
the cytoplasm to surround itself with a wall of cellulose, thus causing 
the formation of the meristem of which the tubercle is composed. The 
author does not believe that the rhizobe has the power of either per- 
forating or dissolving the cell-w ? all. The tubercles of Pisum sativum 
contain also two kinds of rhizobe ; the smaller one is named B. sjphse- 
roides. 
Mycetozoa. 
Hew Myxomycetes. — Mr. T. H. McBride § gives a monograph of 
tbe Myxomycetes of Eastern Iowa, including in the class Plasmodiophora 
Brassicse as the sole representative of a primary division, the Phyto- 
myxinee. A number of new species are also described from Nicaragua, 
Iowa, and Colorado. 
Mr. E. J. Durand || describes several rare Myxomycetes from the 
State of New York, and the germination of the spores of Enteridium 
Bozeanum , the swarm-cells of which are peculiar in having often two 
cilia, one at each end. 
Plasmodiophora Brassicse.^f — In addition to the hosts already re- 
corded for this parasite, Prof. B. D. Halsted finds it on the roots of 
other species of Cruciferse, especially Cajpsella bursa-jpastoris and 
Sisymbrium vulgare. 
Protophyta. 
a. Schizophyceee. 
Cryptoglena amerieana sp. n.** — Under this name Mr. B. M. Davis 
describes a new unicellular blue-green motile organism from a salt 
* Hedwigia, xxxiii. (1894) pp. 22-69 (5 pis.). Cf. this Journal, 1889, p. 791. 
t Flora, lxxviii. (1894) pp. 67-75 (1 pi.). 
f Ber. Deutsch. Bot. Gesell., xii. (1894) pp. 11-7. 
$ Bull. Lab. Nat. Hist. State Univ. Iowa, ii. (1893) pp. 99-162, 377-90 (12 pis.). 
| Bot. Gazette, xix. (1894) pp. 89-95 (2 pis.). 
«[ Bull. Torrey Bot. Club, xxi. (1894) pp. 76-8 (2 fi^s.). 
** Bot. Gazette, xix. (1894) pp. 96-102 (1 pi.). 
