Nov., 1910.] A Floristic Survey of Orchard Island. 
209 
The society forms a narrow interrupted border, not more 
than 4 feet wide of mature fruiting but not tall Hibiscus moscheu- 
tos. Of the secondary species the Hypericum is quite abundant 
at the outer margin of the eastern portion of the zone. The other 
species are very sparse, of the Xanthium and Rosa there is but a 
single plant. 
9. Polygonum-Scirpus society. 
Facies. 
Polygonum emersum. 
Secondary species. 
Typha latifolia. 
Cyperus strigosus. 
Ilysanthes gratioloides. 
Hypericum mutilum. 
Polygonum pennsylvanicum. 
Polygonum acre. 
Agrostis perennans. 
Gratiola virginiana. 
Erechtites hieracifolia. 
Echinochloa walteri. 
Eupatorium purpureum. 
Scirpus fluviatilis. 
Roripa palustris. 
Roripa americana. 
Alisma plantago. 
Amaranthus hybridus. 
Arctium minus. 
Acer rubrum seedling. 
Ulmus americana seedling. 
Hibiscus moscheutos seedlings. 
Cladophora sp. 
Scirpus lacustris. 
This society is 40 feet wide, with the entire surface exposed 
at the present low water level. Hence the extremely hetero- 
genous collection of plants among the secondary species. Dead 
Typha latifolia stalks are so abundant in the western portion of 
the zone as to warrant considering it a dominant plant; but the 
Typha is not at all abundant in the eastern portion of the zone. 
Arctium minus and Alisma plantago growing close together illus- 
trates strikingly the submerged and emersed stages of the society 
and the rapidity with which a new habitat is adopted by 
plants. That the ground has been recently exposed is evidenced 
by the fresh masses of Cladophora. 
10. Scirpus lacustris society. This is a fringing zone 40 
feet wide and extending only about half way across the belt, the 
surface is partly emersed. There is a 20 foot wide sandy beach 
scantily clothed with the Scirpus. 
Secondary species. 
Potamogeton natans. Potamogeton sp. 
Potamogeton pectinatus Nelumbo lutea. 
11. Nelumbo lutea society. A small bed of Nelumbo lutea 
borders the Scirpus lacustris society to the N. N. E. The 
leaves are but few and widely scattered. 
Fifteen feet east of the belt is a public dock, 4 feet wide and extend- 
ing 78 feet out into the water and 54 feet up onto the shore. The 
marsh zones are not formed immediately on either side of the 
dock. On the upper portion of the beach close to the dock, the 
