215 
Number 15 has the twigs, petioles, and lower leaf surfaces 
copiously hairy, the leaves broad, pale, and thin, with the margin 
as in the type. 
Number 16 is V. pennsylvanicum angustifolium of Gray's 
Manual. It is a strikingly distinct form and fully deserves a 
name, but if the species is to be called angustifolium, the varietal 
name must of course be different. This plant is conspicuous by 
the very erect habit of its branches and leaves, the extremely 
tough nature of its stems, and its narrow leaves of a very deep 
green, with the midrib hairy on the lower surface. It strongly 
suggests specific rank. 
Number 17 has the leaves broader than those of number 16, 
but narrower than in regular V. pennsylvanicum, with the margin 
merely denticulate. It preserves the same habit. 
V. ANGUSTIFOLIUM NIGRUM Wood. The question of the exist- 
ence of V. nigrum as a distinct species, as claimed by Britton, 
is not here raised, but I am not in doubt as to the black-berried 
forms described below being mere varieties of V. angustifolium. 
Every form of this species as described above, with the excep- 
tion of number 16, occurs with both blue and black berries. 
These may be either dull or shiny, but are never so markedly 
shiny as in V. atrococcum. 
Number 18 is the typical form described as number 12, ex- 
cept for the black berries. Its twigs are green and warty as in 
the type. Number 19 differs from the preceding only in having 
the midribs hairy on the lower surface, while number 20 has 
neither leaf surface shiny and the lower surface is hairy. 
There are two other forms of var. nigrum of which I appear to 
have missed collecting specimens. One is similar to Number 
20, except that the leaf margin is entire and softly hairy. It is 
noted that this approaches very closely to V. canadense, differing 
only in having the upper leaf surface dull and glabrous instead 
of dull and hairy, and in having black berries. There seems to 
be no good evidence in the fruiting specimen to show that it 
should not be regarded as a black-berried form of VY. canadense. 
The other is a form that appears intermediate between var. 
nigrum and V. atrococcum. It is much taller than V. pennsyl- 
