NOTICES OF BOOKS. 157 
Rhizogens. The thallus of Brugmansia first appears in the form of ~ 
pale yellow spots easily distinguishable from the red-brown tissues 
of the host: under a higher power, it appears usually in the form of 
irregularly-shaped masses inserted in the cambium, and continued on 
one side into the bark, and on the other into the young wood or 
medullary rays; these masses are composed of numerous large cells 
thallus lies completely in the wood, under which circumstances its 
growth is stopped. The growth of the ‘‘floral cushion” (Joralpolster), 
as the author terms the plant in the early state, keeps pace with the 
increase in thickness of the fostering Cissus- root. It destroys the 
neighbouring part of the cambium-zone y its enlargement, and 
becomes shaped like a top or a double cone. Up to this time the 
tissues have remained undifferentiated ; but soon the formation of 
permanent tissue is indicated by widening and lengthening of the cells 
in the lower part of the cushion, the cells of the upper part being still 
filled with protoplasm. It is next seen that development 
of vessels is in progress in the lower portion of the cushion, and inter- 
spaces are found in the young tissues. At t is period more vigorous 
actually increasing in thickness over the parasi The meristem of 
the ower-shoot is now situated in the lower part of the tissue 
se interspaces, and fro like leaves are 
developed, of which there are three pentamerous alternating whorls. 
er a ti e tip also of the growing plant ii € meristematic 
condition, and in lar bun . 
perigone n as a circular rim surrounding the vegetative 
tips of the perigonial lobes, constantly 1 increasing in size and arching 
. over the extremity of the axis; the perigonial fibro-vascular bundles 
afterwards become united with those of the axis. Meanwhile, in the 
inner part of the apical meristem, intercellular spaces have been 
formed, and the andro:ceum has appeared, separated by a shallow furrow 
from the vegetative point. Soon after the appearance of the floral 
parts, the parasite escapes from the investment of the host. The 
inter-meristematic spaces become enlarged, and in the plates of inter- 
ning tissue fibro-vascular bundles are developing. Afterwards the 
ening tissue 
erigone frees itself from the enclosure of the scaly leaves, and the 
columnar andresceum growing by means of meristem lying close under 
the anther-crown, in itself from the perigone. After 
is the circular oe ila 
ovules, uninvested by placentary ee take origin from 
between the soaweate tT yalteady alluded to. 
us and male flowers were an found. The latter have 
a Gainer ecateahank than the hermaphrodite ones, and their inter- 
spaces show no tendency to enlarge for the support of ovules. 
Count Solms holds that Raffesie differ from all related forms by 
reason of the peculiarity that the a * after formation of a 
i ces the ov 
i Eerontiation in the Saante of its growing-point. He —— the 
