228 THE MICROSCOPE, 
the leaf the hairs cling longer, but sooner or later they, too, disappear, 
leaving only the sessile little glands, which in time also take their 
departure. From the prominent veins, however, the hairs and 
glands are never wholly eliminated. There is always a conspicuous 
fringe along the lateral borders, while in the axils the glands become 
clustered and partially embedded in a characteristic manner. 
The young leaves of Catalpa are minutely glandular above, and 
beneath densely silky-villous with hairs which are variously curved 
but entirely unbranched, and in no way glandular. 
THE YOUNG LEAVES OF PAULOWNIA IMPERIALIS, LIEB. 
Trees, shrubs and herbs with variable leaves are not infrequent, 
those on the same plant sometimes differing so widely in form that 
they might readily be mistaken as the product of distinct species, if 
their source was not definitely known. A tree somewhat frequently 
met with in the neighborhood from which I write, the paper 
mulberry, Broussonetia papyrifera, is an instance of this. Its 
leaves are noted for their variable forms, some being almost entire, 
while others are most curiously and irregularly lobed, thus giving 
the tree, when in full foliage, a somewhat startling appearance. But 
if similar variability is not uncommon, it is rare to find the leaves of 
the same tree varying in the form of their epidermal appendages, so 
far, at least, as their hair-like covering is concerned. There are. 
probably instances in which different leaves of the same tree bear 
both simple and branching hairs, but with the exception of those of 
Paulownia, these instances have not come to my knowledge. 
It is a curious and a useful diagnostic feature of the 
Paulownia leaves that some are densely clothed with simple, un- 
branched hairs, each tipped with a little glandular bulb, while 
others on the same tree are still more densely woolly with copiously 
branching appendages, that are not in the least glandular. 
There are consequently two kinds of Paulownia leaves to be 
observed. In the young of both forms each surface is densely vil- 
lous with hairs and glands, but the hairs and glands of one variety 
are united, the latter being minute spherical tips to the former, this 
combination also extending to the petioles. On the same tree, often 
by the side of the preceding, the other form exhibits leaves whose 
lower surface especially is like dull-white velvet, by reason of the 
abundance of its hairy covering. The hairs are not glandular 
tipped, but beautifully and indescribably branched, somewhat like 
those on the leaves of the common mullein, Verbascum Thapsus, L. 
Irregularly distributed over the surface of both these forms of 
Paulownia leaves there are colorless, cup-shaped glands distinctly 
