72 
NATURE NOTES 
their true points of connection are concealed below the surface 
of stem, out of which they appear to rise. 
Stipules takes various forms; sometimes they are foliaceous, 
or leaf-like, as in the garden-pea. This results as a sort of 
compensatory process to make up for the loss of the blade, the 
majority of the leaflets having been converted into tendrils for 
climbing. The galiums, as ladies’ bedstraw, cleavers, &c., seem 
to carry whorls of leaves, but only two (one of which generally 
has a bud or branch arising from its axil) are true leaves. This 
can be readily proved if a thin section be made just above and 
below the position of the whorl. If it be held up to the light, 
besides the circle of woody fibres, which throw off a cord to 
each of the pair of opposite leaves, an outer zone connecting 
these will be observed, from which arise the cords entering the 
stipules. 
In many trees, as the lime,* elm, oak, beech, &c., the 
bud-scales are stipules, while the leaves belonging to them are 
not developed at all. The student should compare them with the 
bud-scales of the horse-chestnut, ash, maple and currant, which 
he will find to consist of flattened leaf-stalks, as rudiments of 
the blade will be seen on the top, there being no stipules to these 
latter trees. 
G. Henslow. 
REVIEWS AND EXCHANGES. 
The Cambridi>e Natural History: Volume ix. Birds, By A. II. Evans, M.A. 
Macmillan & Co., 8vo. Price 17s. net. 
We venture to predict that, of the ten volumes of which this excellent series 
is planned to consist, none will secure a wider popularity than Mr. Evans’s 
treatise on birds. Strange as it may appear, among the many books on birds 
that have appeared of late years, we do not recall any that covers the same 
ground. The author has, as he says in his preface, “essayed the difficult and 
apparently unattempted task of including in some six hundred pages a short 
description of the majority of the forms in many of the families, and of the most 
typical or important of the innumerable species included in the large Passerine 
Order,” prelixing to each group a brief summary of their structure and habits. 
An introductory chapter — all too brief — deals with general external and skeletal 
characters, classification, distribution and migration ; but a vast range of most 
interesting topics, such as variation and flight, are omitted, as beyond the scope 
of the work. 
.Space does not permit us at present to quote as an example of the practic.al 
character of the book the whole of the description of a feather, but the following 
is an admirably concise treatment of part of this subject : — “ The colour of feathers 
is due to one of three causes, first, an actual pigment may be present in certain 
corpuscles, or in diffused solution, and the tint does not then vary according to 
the incidence of the light ; secondly, it may arise from a pigment overlaid by 
colourless structures in the form of ridges or imbedded polygonal bodies ; here 
* The reader is referred here to an article “Notes on Buds ” in Nature 
Notes (Jan., 1897, p. 6) for further details. 
