278 Rhodora [ NovEMBER 
I. SACCHARATA, var. Amesii. ‘Trunk 2- 3- 4- or 5-lobed, 4-10 
mm. long, 2-5 mm. wide and high; roots very fine: leaves 8-30 
cm. long, 1-1.5 mm. in diameter, slender, finely pointed, green and 
erect. when gregarious, spreading when scattered, very narrowly 
winged to the surface of the soil, quadrangular, the frontal edges 
elevated, the back flattened; stomata few, bast-bundles none: velum 
1-8 indusiate; sporangia 4 mm. long and 3 mm. wide, white or with 
a few scattered dark brown cells, very turgid from abundance of 
spores: gynospores 420-600 y, averaging 510 y long, rather sparsely 
covered with low, fine, rough granules and thin, short, low walls, 
often reticulated; androspores 28-32 y long, very finely granulated. 
Very common in shallow streams and ponds about Easton, Massa- 
chusetts, in fine gravel with or without silt, often forming a dense 
border a few feet to a rod wide, just at the lowest stage of the water, 
soon disappearing if exposed to the air. It is peculiar in the various 
lobing of the trunk. Two handfuls obtained by scraping the soil 
just deep enough to include the plants and then washing out, were . 
found to have an aggregate of 204 individuals, of which 95 were 
2-lobed, 94 were 3-lobed, eleven 4-lobed, and four s-lobed, a much 
larger percentage of other than two-lobed trunks than has been 
found before in the United States except in the three 3-lobed species 
of the Pacific coast. The only other species that shows a consider- 
able tendency toward a plurilobate form is Z. Zuckermani, Which in 
some places has 20% with three or more lobes but it is not constant 
in this trait. Most species may have an occasional plant with a 
3-lobed trunk, but our other local ones rarely show a half of one 
percent so developed. The variety here described differs from / 
saccharata in its very fine leaves, with few stomata and heterolobing 
of its trunk. 
I have seen what is apparently the same thing from the following 
localities: Lantern Hill Pond, North Stonington, Connecticut, 
C. H. Bissell, Head of Hambury Cove, Lyme, Connecticut, Dr. C. 
B. Graves, Peeksville, New York, W. H. Leggett. 
Isoetes riparia has been thought to have a place in the New 
England flora, but after a thorough study of Dr. Engelmann's mate- 
rial I became convinced that it was not found here, or at least that 
all previous reports were erroneous. I have recently! dealt with 
most of the material so referred, but several collections made about 
Uxbridge, Massachusetts, between 1831 and 1864 by Robbins, were 
1 Bull. Torr. Bot. Club. 30: 359. 
