210 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
which, have a more or less nearly vertical position have a normal 
symmetry of structure, from which there is a deviation in those which 
are placed at various angles, the supporting, the assimilating, and even 
the vascular tissues having a bilateral structure, and the branches being 
flattened dorsiventrally. 
Buds and Stipules.* — The structure and position of the leaf-buds 
and stipules is described in a very large number of additional instances 
by Sir John Lubbock, the observations confirming his previous conclu- 
sion that the most usual purpose of stipules is to protect the leaves 
while in the bud, sometimes their own leaf, but, as a rule, the younger 
one. In some cases they themselves perform the function of leaves, 
replacing them entirely in a few cases ( Lathyrus Aphcica). In others 
they serve to hold water ; in some they develop into spines ; in some 
into tendrils ; in others they become glandular. The outer scales which 
protect the winter-buds may be classed under seven heads, viz. : — 
(1) Pedestals of last year’s leaves ( Pyrus Aria) ; (2) modified bases of 
leaves (maple, horse-chestnut); (3) leaf-blades (Viburnum Lantana); 
(4) modified leaves ( Viburnum Opulus, willows); (5) stipules (poplar, 
oak, beech); (6) connate pairs of stipules belonging to the same leaf 
(elm, Castanea ) ; (7) connate pairs of stipules belonging to different 
leaves (hop, Gardenia, and other liubiacens). 
Disguises in Bud Arrangement.} - — Mr. G. H. Shull has attempted 
to trace to deviations from a general law some of the more striking 
variations from the normal arrangements of organs in the bud. He 
concludes that most cases of branch and flower arrangement may be 
explained by the law that a bud, real or potential, occurs in the axil of 
every leaf, and terminates every axis. If a bud is removed from the 
axil of a leaf by adnation or by development into a branch, a secondary 
axillary bud may form in the axil of the leaf ; and if that is also removed, 
a tertiary axillary bud may be formed. Bud pressures explain reduction 
of bracts and their failure to appear, as well as many modifications in 
the normal order of anthesis. 
Fibrovascular Bundles of Leaves.}; — M. A. Chatin discusses the 
number and symmetry of the fibrovascular bundles of the appendicular 
organs as an indication of perfection of organisation. Among Corolli- 
florae the number of bundles that enter into the composition of the petiole 
is very rarely more than one. The exceptions are chiefly non-chloro- 
phyllous parasites or plants with very large leaves. The Apocynaceae, 
Jasminaceae, Gesneracea3, and Labiatiflorae are especially noteworthy for 
the constancy of the unital structure. When the bundles are numerous, 
they’ are arranged either in a single circle, or in two or more circles, or 
are scattered through the thickness of the petiole. Among the perigynous 
Gamopetalaa the unital type of bundles in the petiole is not nearly so 
universal. They may be divided into two grouj)S, — one, represented by 
the Rubiaceae and Caprifoliaceae, with only one ; the other, comprising 
the Compositae and allied orders, with numerous petiolar bundles. 
* Journ. Linn. Soc., xxxiii. (1897) pp. 202-69 (4 pis. and 133 figs.). Cf. this 
Journal, 1895, p. 653. 
t Bot. Gazette, xxiv. (1897) pp. 427 32 (2 figs.). 
t Comptes Rendus, exxv. (1897) pp. 343-50, 415-20, 479-84, 997-1004. Cf. 
this Journal, 1897, p. 306. 
