1903] Eaton,— Three New Varieties of Isoetes 277 
1896 and has since sent me specimens. This makes a second 
authentic station for that species for the State, as I have already 
recorded it in Ruopora, I, 1899, 93, from a specimen sent me by 
Mr. W. S. Harris who collected it on the shore of Cobbett’s Pond, 
Windham, on July 23, 1895. The label reads “Scarce. A tall slen- 
der bush, with slender clusters of berries." — WALTER DEANE. 
THREE NEW VARIETIES OF ISOETES. 
A. A. EATON. 
IT has been frequently remarked that although the genus Isoetes is 
world-wide in distribution, the søecies are apt to be very circum- 
. scribed in range, often confined to a very small area. As new col- 
lections are made, however, it is found that old species are often 
extended in range as might be expected; but it has also been found 
that species at first considered to be distinct are only conditions in 
a series, and plants from new localities often fill the gaps. One 
remarkable instance is in the case of Z. riparia and J. saccharata} 
whose characters are found in such a series that the question arises 
if the latter is really more than a variety of the former. 
In some instances the plants of a drainage area may be consid- 
ered as incipient endemic species, evidently from the same original 
source as those of other water-courses, but presenting constant or 
slightly varying differences, apparently caused. by geologic con- 
ditions in some instances. 
The vicinity of North Easton, Massachusetts, exhibits a marked 
instance of this. The soil is mostly a fine gravel, and no clay has 
been found. During the past season I have found an abundance of 
Isoetes, but only three familiar ones, namely, Z. Zuckermani, and J. 
echinospora, vars. robusta and muricata. Late in 1902 Mr. R. M. 
Grey found a small species abundant in the ponds of this vicinity 
and my search has revealed two others, all of which, although show- 
ing some distinctive characters, are best regarded as varieties. The 
first to be treated is a variety of the very variable Z. saccharata 
Engelm. and may appropriately be named for the botanist near 
whose home it is abundant. 
! Bot. Gaz. 36: 187-202. 
