430 Remarks on the Genera Callitriche and Elatine. 
The character of E. triandra, is to have leaves opposite, flowers 
sessile, and opposite stamens, and petals three ; but there is a plant 
found originally in a remote part of America, but now observed 
throughout all the United States, which I have been often sur- 
prised that no one has compared with E. triandra: I allude to the 
Crypta minima, Nutt. In this the flowers are equally sessile, and 
sometimes (?) opposite ; the stamens and petals varying from two to 
three. In both, as in all the genus Elatine, the seed is cylindrical, 
obtuse at both extremities, curved, longitudinally striated, with 
rows of transverse impressed punctures. Nuttal appears to have 
been aware of the athnity of Crypta with the genus Elatine in 
general ; but his observations seem to have been made alone on 
E. alsinastrum, and his idea of the generic character taken from 
old books: I am not, therefore, surprised when he says that the 
difference of habit of the two genera is considerable, nor at the 
other remarks he has made at p. 228, of Vol. I. of his Genera. 
Nuttal (Vol. II. Additions) describes the calyx of his plant as two 
leaved: Schkuhr figures his E. triandra in the same way, al- 
though with three petals and stamina, remarking that there is a 
vacancy left for the third calycine segment. The first plants seen 
by Nuttal well deserved the specific name of “ minima ;” but 
since the plant has been better known, I have received specimens 
from the neighbourhood of Boston, from my friend M. Greene, 
which equal in size any of the opposite leaved species of Elatine: 
I may now draw the conclusion that Crypta minima is a congener, 
and very closely allied, indeed, to E. triandra. But are these to 
be separated from Elatine ? I think not: there is no difference in 
habit ; and the circumstance of the reduction of the number of 
stamina, is weakened by their acknowledged variation in the ge- 
nus. The Peplis ? diandra, Nutt. whatever becomes of it, must 
not be confounded with Crypta minima, as has been done by M. 
Guillemin in the Dict. Class. Vol. XIX. p. 194. 
The above observations on E. triandra, I regret to say, I have 
been obliged to make from Schkuhr’s figure and description, havi 
never been able to obtain specimens of the plant ; and had Schkuhr’s 
accuracy not been well known, I might have been induced to sus- . 
pect some mistake ; the more so, that there does exist, in my own 
and various other herbaria, a plant extremely similar, and which 
has been often confounded with the FE. iriandra; but this new 
species has eight stamina, and answers, in all respects, to Linnzus’s 
character of the genus. I propose to call it EL. nodosa, in allusion 
to the remarkably sessile globose axillary fruit. 
The characters of the species of Elatine are now as follow: 
Sect. I. Stigmata linear short, leaves verticillate. 
].. E. Alsinastrum; leaves vertzcillate, flowers sessile verticillate. 
Sect. II. Stigmas mere points, leaves opposite. 
§ 1. Stamens twice as many as the petals. 
2. E. hydropiper ; leaves opposite, oblong ; flowers alternate, on 
peduncles that are half as long as the leaves, with eight stamens 
and four petals ; calycine segments short and erect, 
