1877. ] Plants in New Hampshire and Vermont. 91 
reach the mouth of the Lower Ammonoosuc and Wells rivers. 
There the Labrador tea (Ledum latifolium) is altogether want- 
ing, and the arbor vitæ and high cranberry tree become much less 
numerous. 
The forests which cover the high terraces at the mouth of 
these rivers are composed of pitch and red pines (Pinus rigida 
and P. resinosa) and white oaks ( Quercus alba). 
Mountain rice grasses ( Oryzopsis Canadensis and O. asperi- 
folia) first appear in these woods, which would indicate that they 
as well as the trees are Alleghanian. A few miles south of this, 
at Haverhill, N. H., hackberry (Celtis occidentalis) and bitter 
hickory ( Carya amara) are added, and below this point the Alle- 
ghanian type of vegetation predominates in the immediate vicin- 
ity of the river. Arbor vite and the mountain alder (Alnus 
viridis) are the only Canadian species present, and these find 
their southern limit at the White River Narrows between Hano- 
ver and White River Junction. 
Azalea nudiflora is the most noticeable addition before reach- 
ing North Charlestown, where we abruptly meet with a group of 
trees common throughout the valley in Massachusetts. These 
are chestnut ( Castanea vesca), yellow oak (Quercus coccinea, var. 
tinctoria), shell-bark hickory ( Carya alba), button-wood (Plata- 
nus occidentalis), and, growing in their shade, the huckleberry 
(Gaylussacia resinosa) and the rattlesnake weed (Hieracium 
venosum). 
Bellows Falls, Vt., seems to be the next place for the appear- 
ance of another group, apparently marking the northern limit of 
dwarf sumac (Rhus copallina), shrub oak ( Quercus ilicifolia), 
summer grape (Vitis estivalis), liberty tea (Ceanothus Ameri- 
canus), eranesbill (Geranium maculatum), Aster levis, Solidago 
gigantea, Bidens chrysanthemoides, Cassia Marilandica, butterfly 
weed (Asclepias tuberosa), spice bush (Lindera Benzoin), fox- 
tail grass (Aleopecurus pratensis and A. geniculatus), Calyste- 
gia spithamea, and Vaccinium vacillans ; quite an array of species 
which seem to have found these falls an effectual barrier to their 
march northward. 
Along the valley between Bellows Falls and Brattleboro are 
the high blue-berry ( Vaccinium corymbosum) and Andromeda 
ligustrina, but it is not quite certain whether or not they should 
belong with this group. : 
__The cotton-wood (Populus monilifera) first appears on an 
island in the river near the north line of Westmoreland, N. H., 
