1895.] Anatomical and Physiological Researches. 497 
Pyrenomycetes, but they were found in a very imperfect con- 
dition. Their occurrence was always merely local; they did 
not penetrate the entire tubercle, and the mycelium seemed 
constantly to decrease in size towards the center of the 
tubercle. Another fact observed was that the fungi only oc- 
curred in degenerated or decayed parts of the roots and tu- 
bercles. From this fact we might conclude that the fungi 
were saprophytic in nature, and had nothing to do with the 
malformation of the roots. 
Comparing these tubercles with similiar ones on the roots 
of other plants, the author considers them to be nearly 
identical with those which Brunchorst described from 
Crategus prunifolia.?. The cause of their formation may be 
sought in purely external conditions, such asa sudden change 
in the nutrition of the plant or in some mechanical obstruc- 
tion. In the present case it was found that the development 
of the tubercles was especially frequent whenever the roots 
struck sterile layers of sand, and they were thus at once de- 
prived of their usual nourishment.—THEO. HOLM. 
Studies upon galls.* 
Pliny was the first to use the word gall (ga//a) as a name 
for these well-known outgrowths upon plants. The word has 
Since been used for any pathological formation which appears 
as a thickening or swelling, and which is caused by insects, 
spiders, or fungi. The injury may, however, be of quite a 
varied character, and botanical terminology gives a large 
number of terms for distinguishing between the various ig re 
under which parasitism or pseudo- parasitism may o 
Vuillemin* for instance has proposed the terms adtibiodts” 
and ‘‘symbiosis,” according as the interference is or is not 
injurious to the host. But while this writer considers para- 
Sitism as intermediate between anti- and sym-biosis, Sarauw® 
uses parasitism as embracing all the various forms of anti- 
and sym-biosis. : 
The result of an antibiosis is probably arise the sets e 
und den Piavrunn Un tersuch. im bot. ioe te 5— 
* Kiistenmacher, Max: Beitrage zur Recath ss der Gallenbildungen - a 
rlcksichtigung des Gerbstoffes. Pringsheim’s Jabrb, £ wiss. Bot. 26: — 
* Vuillemin, ay Antibiose et symbiose. Assoc. fran ancaise pour 1’ ane aoe 
Sciences. 18: 
Y spr nev oy Geoke F. L.: Rodsymbioseog Mykorrhizer. Bot. Tidsskrift. 18: 
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