1915] CURRENT LITERATURE 61 
contribution to our knowledge of the flora of China. The present part, like 
the preceding ones, is based primarily on a critical study of plants collected 
in western China by E. H. Witson, but it includes also citations of collections 
made by Henry, Faurie, JACK, PuRDOM, SARGENT, TAQUET, and others. 
Upward of too species and varieties new to science are recorded in some 40 
different genera. The importance of the work lies, not only in the record of 
new plants, but also in the incorporation of much synonomy and bibliography 
from scattered publications.—J. M. GREENMAN. 
NOTES FOR-STUDENTS 
Hereditary symbiosis.—One of the most remarkable of recent botanical 
discoveries, that of hereditary symbiosis between bacteria and seed plants, 
was made independently by Mrrne and von FABER,’ thus adding another to 
the notable list of great simultaneous achievements. As early as 1894 TRIMEN 
noted the persistent presence of small knotlike excrescences on the leaves of 
certain tropical Rubiaceae of Ceylon. In 1902 ZIMMERMANN noted the con- 
Stant presence of bacteria in these structures, at least in four species from 
Java, whereupon he referred to them as bacterial knots (Bacterienknoten). 
Since ZIMMERMANN did not take up the question of the origin of the bacterial 
knots, von FaBER went to Buitenzorg in 1910 to make an extended study 
of them. A preliminary report of his early observations was made in 1011, 
and a full account followed in 1912.8 
Von FaBer investigated the symbiotic relations of five species of Rubia- 
ceae, viz., Pavetta indica, P. angustifolia, P. lanceolata, P. Zimmermanniana, 
and Psychotria bacteriophila. In the closed buds the bacteria are found in 
resinous masses in among the leaf primordia. As the leaves develop, the bac- 
teria enter them through certain precociously appearing stomata and pass into 
intercellular spaces, Soon there is differentiated in the leaf a special tissue com- 
_ Posed of small cells rich in chlorophyll. Between these cells there develop 
capacious intercellular spaces, which the bacteria occupy henceforth. By the 
time the bacteria have occupied these spaces, the precocious stomata through 
which they entered the leaf become closed. From pure cultures of the host 
plants it was discovered that the bacterial tissue is derived from primordia 
which without the presence of the bacteria develop into a secretory reservoir, 
in which there accumulates a resin similar to that noted above as present in the 
bud. It is probable that the bacteria are attracted by this resin. Caref 
Study of every Stage in the life history of the host plants showed that the 
bacteria are always present. They become inclosed in the ovary at flowering, 
ee iain 
7 Von Faser, F. C., Uber das staindige Vorkommen von Bakterien in den Blattern 
verscniedener Rubiaceen. Bull. Dép. Agric. Ind. Néerl. 46: pp. 3. 1911. (See Bot. 
Centralbl. 119:351. 1912.) 
*——__ Das erbliche Zusammenleben von Bakterien und tropischen Pflanzen. 
Jahrb. Wiss. Bot. 51: 285-375. figs. 7. pls. 3. 1912. 
