410 BOTANICAL GAZETTE [NOVEMBER 
Hinatikatl, Central America.—G. S. West (Journ. Bot. 49:82—89. 1911) under 
the heading “ Algological notes’’ characterizes a new genus (Oligochaetophora) ; 
the genus is based on Polychaetophora simplex.West, which was found orig- 
inally growing on submerged portions of various aquatic flowering plants at 
Donegal, England.—J. M. GREENMAN. 
Cecidology.—Among the most important of the recent papers on galls is 
that by Denizor™ on the gall of Andricus radicis. This gall occurs on the 
roots of at least three species of oaks, and appears to resemble somewhat the 
American twig gall caused by A. punctatus Bassett. The gall is plurilocular, 
but its histological structure is very similar to the unilocular gall caused by A. 
sieboldi. e gall is made up primarily of parenchyma tissue, and each 
larva is surrounded by a definite structure as follows: (1) a zone of parenchyma 
tissue well filled with starch and known as the nutritive zone; the starch 
disappears with the growth of the larva and is supplanted by tannin and oil; 
(2) a protective zone of scelerenchyma tissue containing albuminoids and 
tannin. There is a gradual transition between these two zones. The supet- 
ficial part of the gall is made up primarily of cork cells whose contents are 
reduced to a thin layer of tannin deposited against the inner walls. e€ 
tannin exists in all parts of the gall, but is most abundant in the parts referred 
to above, and increases in amount with the decrease in starch. It causes a 
coagulation of the contents of the cells, persisting in the protective cells in the 
orm of grains, and in the cork cells as a thin peripheral layer. The reviewer 
has observed similar conditions in several of our American galls. ; 
Another exceptionally good piece of work is that of Houarp™ on the action 
of certain scale insects on the plant tissues. His studies were restricted to 
Asterolecanium variolosum, A. thesii, and A. algeriense on Quercus peduncularia, 
Q. sessiliflora, Q. pubescens, Pittosporum tobira (an Asiatic plant), Templetonia 
retusa (an Australian plant). In all cases these insects cause cone-sha 
swellings, and in the tip of each cone a depression in which the insect is located. 
The swellings are due partly to thickening of the bark and partly to a modifica- 
tion of the vascular bundles. The galls differ in accordance with the response of 
the vascular bundles to the stimulating influences of the insects; the more com- — 
pact the bundle, the greater the resistance. If the bundles are compact, the 
hypertrophy of the medullary rays is slight and the bundles only slightly sepa- 
rated, thus making it difficult for the parasite to reach any great depth. In 
the case of A. variolosum, the vascular bundle responds to the action of the in- 
sect in the formation of new wood only. This new wood possesses an abnormal 
structure due to the sucking of the insect interfering with the normal differentia- 
© Denizor, M. Georces, Sur une galle du chéne provoquée par Andricus radicts 
(Cynipide). Rev. Gén. Botanique 23:165-175. IgIt. 
: * Hovarp, C., Action de Cécidozaires externes, appartevant au genre Asteroleca- 
mium, sur les tissues de quelques tiges. Marcellia 10:3-25. 1911- 
