ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
353 
contains young tracheids from a length only slightly exceeding the height 
of the meristem-cells to that of fully developed tracheids ; that each 
young tracheid contains only a single nucleus ; and that the fully- 
developed trachei’ds have a minimum length about ten times the height 
of the meristem-cells. 
Intraxylary Phloem.* — Dr. Solereder has examined the anatomical 
structure of a number of species of Thynielaeacese and Penaeaceae in 
which bicollateral vascular bundles occur, and finds intraxylary phloem 
to be a constant character for these families. 
Stem of Compositae.f — According to Herr Schumann, there occur 
in some Compositae, as, e. g. in Carlina acaulis, vascular bundles which 
are limited in growth in consequence of being completely surrounded 
by a sheath of bast-fibres or similar elements, resembling wood-fibres in 
their form and in the nature of their walls, except that these are thicker 
and not so copiously pitted as in wood-fibres ; no transitional forms 
occur except in some Carduea3. The bast-fibres of Composite are almost 
always septated. Secondary medullary rays are scarcely ever found, 
except in Solidago longifolia, where there are a very few. The primary 
medullary rays are usually composed of lignified fundamental cells. 
The continuous ring of wood is generally very wavy. The pitting of 
the wood-fibres is always strongest on the tangential walls ; on the 
radial walls it is occasionally altogether wanting. The pith is dis- 
tinguished by the thinness of its walls, though occasionally a few of its 
cells are sclerotized. The cambium-ring is often very greatly reduced 
in size. 
Supporting-bundles in the Stem of Cichoriaceae.J — From an ex- 
amination of various stages of development, Dr. O. Kruch has arrived at 
the conclusion that the importance attributed by Van Tieghem and 
Morot to the pericycle is not exhibited in the case under consideration. 
He believes that in the stem, branches, and leaf-stalks of Liguliflorae 
we have no system of sustaining bundles belonging to the pericycle, 
but, on the other hand, a system of mechanical cords of procambial 
character belonging to the sieve-portion of the vascular bundles. 
Bark of Leaf-stalks.§ — M. L. Morot points out that in the leaf- 
stalk of certain species of Simarubiaceae and Sapindacefe the bark 
derives its origin from the hypodermal layer of cells, the bark itself 
sometimes consisting of as many as six or eight layers. 
Constituents of Lignin.|] — Herr G. Lange has subjected beech- wood 
and oak-wood to very careful analysis, after removing all impurities by 
water, 5 per cent, hydrochloric acid, alcohol, ether, ammonia, and soda- 
lye, and then exposing for a long period to the action of caustic potash 
at a temperature of 185° C., for the purpose of separating the cellulose 
from the lignic acids. In addition to the cellulose a substance was 
found soluble in alkalies, which could be separated by alcohol into two 
lignic acids. 
♦ SB. Bot. Ver. Munchen, Jan, 13, 1890. See Bot, Centralbl., xli. (1890) p. 250. 
f Bot. Centralbl., xli. (1890) pp. 193-6. X Malpighia, iii. (1889) pp. 358-66. 
§ Journ. de Bot. (Morot), iii. (1889) pp. 407-8. 
11 Zeitschr. f. Physiol. Cheraie, xiv. pp. 15-31. See Bot. Centralbl., xli. (1890) 
p. 23. 
