BICKNELL : FERNS AND FLOWERING PLANTS OF NANTUCKET 65 
monograph of the genus Lefidium, which appeared in 1906. It 
developed that Mr. Wilson’s collection included specimens of Z. 
virgimicum and of L. densiflorum, together with a new species which 
was described by Doctor Thellung as Lepidium neglectum (Bull. 
Herb. Boiss. II. 4: 708. 1904). This description makes it 
plain that the new species is precisely the Van Cortlandt Park 
Lepidium already referred to. Doctor Thellung had, in 1903, 
referred the plant, as had Doctor Robinson, to the Lepidiame 
medium of Greene. Its relationship to this southwestern species is 
indeed close, but an examination of authentic specimens of JZ, 
medium does not allow me to doubt that Thellung was finally right 
in regarding the two plants as distinct. 
Lepidium neglectum is so nearly intermediate between L. virgini- 
cumand L. densifiorum that the question of hybridization is readily 
suggested. Yet in the behavior of the plant and in its environ- 
ments as I have observed it, no evidence has appeared, aside from 
the mere fact of association, that it is not a perfectly true species. 
The three plants sometimes occupy the same square yard of space, 
yet L. neglectum is also found growing with L. wvirginicum in 
localities where ZL. densiforum is unknown. 
Lepidium neglectum, although discussed by Thellung espe- 
cially in its relation to ZL. densiflorum has much more the aspect of 
L. virginicum. It is, indeed, sometimes difficult to distinguish 
from forms of the latter except by reference to the position of the 
cotyledons in the seed, which is always conclusive — accumbent in 
L. virginicum, incumbent in ZL. neglectum. The most obvious 
differences from L. virginicum are more elongated racemes and 
shorter-pedicelled and often larger and more orbicular capsules, 
which become over 3 mm. long and broad; it differs also in the 
form and texture of the leaves and in the character of the obscure 
pubescence. In the field it may be useful to recall that it begins 
to flower considerably earlier than L. virginicum. 
There need be no uncertainty as between L. neglectum and L. 
densiflorum. The former is at once set apart to the eye by its 
much larger and less crowded, more broadly orbicular capsules, 
and by its petals, which are always more or less obvious except in 
the terminal or later flowers, where they may be rudimentary or 
even absent. 
