ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 447 
into the three tribes Sambuceae, Viburneae, and Lonicereae. The genera 
are not, as a rule, to be distinguished by anatomical characters ; but this 
is the case, in some instances, with the species. Sambucus appears to be 
invariably characterized by the presence of tannin-receptacles. The 
anatomical characters point to a near alliance between the Caprifoliaceae 
and the Rubiaceae. 
Structure of Christisonia.* — Mr. W. C. Worsdell describes the 
structure of several parasitic species of this genus belonging to the Oro- 
banchaceae, and the modifications in that structure induced by their 
mode of life. These are mainly as follows : — The branching and ana- 
stomosing root-system ; the rhizome-like character of the roots and the 
absence of root- hairs; the development in one species of tubers from 
which the haustoria and the young lateral roots and stems are produced, 
and which serve as store-houses for the nutrition of the plant; the 
modified anatomical structure of the cylinder of the root, in which the 
xylem has become reduced and the phloem correspondingly developed ; 
and the reduction of the conducting tissue of the stem, correlated with 
the absence of foliage-leaves, which are replaced by scales. The tubers 
of C. subacaulis belong to the root. The haustorium is of exogenous 
origin, as in Mhinanthus. 
(4) Structure of Organs. 
Doubling and Reduction in Flowers.! — According to Dr. L. J. 
Oelakovsky, the true nature of a normal doubling of the parts of a 
flower cannot always be determined from the phenomenon itself. It is 
not a division of original simple leaves, but a union, or at least an 
approximation, of parts which were at first distinct and at an equal 
distance apart. Normal doubling is the result of an incomplete passage 
from a larger to a smaller number of parts. In some Hypericaceae and 
Malvaceae, and in the Myrtaceae, the petals are the result of a basipetal 
branching from the base of the polyandrous primordia ; in the Primu- 
laceae from the base of the simple rudiments of stamens. 
Opening and Closing of Flowers. J— From a series of observations 
on a number of different flowers, Herr F. Oltmanns states that, in the 
ease of ephemeral flowers, the time which they remain open is greatly 
lengthened by keeping them in the dark ; and they then behave like 
flowers which open and close periodically. Those flowers which only 
close late in the evening agree in all essential points with leaves which 
exhibit nyctitropic movements. In the case of flowers which open 
at night, even a diminution of light causes them to open, an increase of 
the light to close. 
Flower of Naias.§ — Herr P. Magnus enters into a full description 
of the morphology of the male and female flowers of Naias , and dissents 
in several points from the interpretation of Schumann. 
* Ann. Bot., ix. (1895) pp. 103-36 (2 pis.). 
f SB. K. Bohm. Gesell. Wiss., 1894, 142 pp. and 5 pis. (German). Cf. this 
Journal, ante, p. 68. 
$ Bot. Ztg., liii. (1895) l te Abtheil., pp. 31-52. 
§ Ber. Deutsch. Bot. Gesell., xii. (1894) pp. 214-24 (1 pi. and 3 figs.). 
2 g 2 
