Besleria lutea, Linn., a New Example of Water-calyx. 
. BY 
MONTAGU DRUMMOND, B.A., F.L.S., 
Lecturer in Plant Physiology , University of Glasgow. 
jTJESLERIA lutea , Linn., is a small Gesneraceous shrub, which grows in 
xJ moist mountain woods in Jamaica and several other West Indian 
islands, as well as in north-eastern South America. It occurs plentifully 
in the vicinity of Cinchona, in the Blue Mountains of Jamaica, where the 
peculiar swollen appearance of its calyx attracted my attention during my 
stay at the Hill Garden in the late summer of 1913. A closer examination 
of flower-buds showed that the tube of the gamosepalous calyx is greatly 
inflated, especially towards its base, so that the corolla and essential organs— 
which lag far behind the calyx in development — are, at this stage, enclosed 
in a bell-shaped cavity of considerable size. In the bud, this cavity is com- 
pletely filled with a clear watery liquid, which is prevented from escaping, 
chiefly by the circumstance that the closely apposed, connivent lobes of the 
calyx-limb are slightly twisted around one another. The margins of the 
calyx-lobes further interlock by means of cellular sutures. 
The calyx-cavity remains filled with ‘ water 5 after the corolla has burst 
through the tip of the calyx, and even after the flower is fully open. The 
application of gentle pressure to the calyx of a flower in full bloom causes 
liquid to exude from its apex. During the ripening of the fruit the calyx 
becomes still more distended, and assumes a globose shape, thus keeping 
pace with the enlargement of the ovary to form a spherical berry. Some 
considerable time before the fruit matures, liquid disappears entirely from 
the calyx-cavity, which thenceforth contains air. 
The calyx is a somewhat massive structure, but its anatomical con- 
struction is simple. The outer epidermis is small-celled, and bears scattered 
simple hairs composed of from one to three thick-walled, cylindrical cells, 
the terminal one of which tapers to a point. A few stomata are present on 
the outside of the young calyx, but these are very soon replaced by numerous 
small lenticel-like structures. The peripheral parts of the mesophyll consist 
of closely-packed, slightly collenchymatous elements ; the central portion is 
thin- walled and well provided with intercellular spaces. The inner epidermis 
is large-celled, quite devoid of stomata, and bears numerous large capitate 
[Annals of Botany, Vol. XXXIV No. CXXXVI. October, igao,] 
