1908] Flora of the Boston District,— II 61 
SELAGINELLACEAE. 
SELAGINELLA. 
. rupestris (L). Spring. Dry rocks, rather common. 
S. apus (L.) Spring. Wet places; locally abundant in northern 
portion, occasional elsewhere; probably often overlooked. 
ISOETACEAE. 
ISOETES. 
I. Dodgei А. A. Eaton, var. Robbinsii А. A. Eaton. (I. canadensis, 
var. Robbinsit A. A. Eaton, RHoDoRA, v. 279. 1903.) In Mul- 
berry Meadow Brook, Easton (А. А. Eaton). 
I. Eatoni Dodge. In Tuxbury’s Pond, Amesbury (А. A. Eaton & 
Raynal Dodge); in Parker River, Byfield (Raynal Dodge). 
Scarce. 
I. echinospora Durieu, var. Braunii (Durieu) Engelm. Abundant 
throughout, mostly in mud, but sometimes on sandy shores and 
bottoms of ponds and large streams. 
Var. muricata (Durieu) Engelm. Reported from twelve localities, 
covering the northern and southern limits of the district. Usually 
plentiful where found at all. 
I. Engelmanni A. Br. In ponds and ditches, mostly over a clay sub- 
soil; common in the northern part of the district, but not re- 
ported south of the Blue Hills. 
I. foveolata A. A. Eaton, var. plenospora А. A. Eaton. In ponds, 
North Easton (A. A. Eaton). Plentiful. 
?I. Gravesii A. A. Eaton. Arlington Brook (Wm. Boott). The 
specimens seen are fragmentary and unsatisfactory. 
I. saccharata Engelm., var. Amesii A. А. Eaton. In ponds on gravelly 
bottom, North Easton (А. A. Eaton). Abundant. 
I. Tuckermani A. Br. In ponds on sandy bottom, common. 
? Var. Harveyi (A. A. Eaton) Clute. Fresh Pond, Cambridge 
(Wm. Boott). All material seen has been fragmentary and un- 
satisfactory. 
(Note.— From the material examined, the genus would appear to 
