1903] DISTRIBUTION OF ISOETES SACCHARATA 189 
It will be seen then that within the last ten years Jsoetes sac- 
charata and its forms have been traced from its original station 
completely to the head of the bay. Wicomico River is yet the 
most southern station known, but it is not improbable that a care- 
ful exploration will result in its discovery in the fresh-water 
estuarine portions of the more southern tributaries of the bay. 
For the sake of completeness and to facilitate further study 
of the several colonies now known, as well as to serve as an 
index to the map, I insert the following list comprising all the 
known stations, with such data as I have been able to gather 
regarding each. The figure preceding each name agrees with 
the corresponding station as indicated on the map. In each 
case the station is at the point in which the index line intersects 
the shore line. 
1. Salisbury, Md.—On a label in the herbarium of G. Engel- 
mann, St. Louis, Mo., now in the Missouri Botanical Garden, the 
type locality is described thus:5 “Shores of Wicomico River, 
one mile {1.6*"] below the town of Salisbury, eastern shore of 
Maryland, on gravel, covered by a thin layer of mud deposited 
by the tide ; alternately covered and exposed by the tide... . . 
Growing in the society of Sagittaria pusilla (S. subulata {L.| 
Buchenau), Tillaea simplex (T. aquatica L..), Hemianthus micran- 
themoides (Micranthemum micranthemoides | Nutt. | Wettst.) etc.; 
first found Sept. 15, 1863. Wm. M. Canby.” This label, which 
bears the date September 8, 1866, evidently belongs to a type 
specimen. In a letter to the writer, Canby explains that the 
Original station is a sandy or gravelly slope on the south side of 
the river. 
In September 1895 T. C. Palmer, in an attempt to visit the 
type locality, found the species growing at Williams Point on 
the Wicomico River. 
2. Seaford, Del., is situated at the confluence of the north 
and south branches of the Nanticoke River, and only 5*" below 
the head of tide water. A label in the Engelmann herbarium, 
>A similar but somewhat ambiguous description of the type locality occurs in 
Engelmann’s paper on “The Genus Isoetes in North America.” Trans. St. Louis 
Acad. Sci, 4: 382. 1882. 
