2o6 



The Ohio Naturalist. 



[Vol. XI, No. 1, 



Seedling trees. 



Acer rubrum. 

 Gleditsia triacanthos. 



Quercus palustris. 



Ground cover. 



Cyperus strigosus, small mat plants. Spirodela polyrhyza. 

 Riccia tiuitans. Brachythecium rivulare. 



Riccia sp. Cladophora sp. 



Phialea scutula on dead Hibiscus stems. 



This zone is -lO feet wide and the ground surface is entirely 

 above the water, but so recently exposed that the stranded 

 Spirodela and Algae are still green. The Hibiscus roots form 

 small hillocks on which the Spirodela and Algae become stranded 

 and on which the Riccia is very abundant. The taller herbs form 

 a sparse weak growth due to the density of the Hibiscus which 

 forms a 7 foot wall difficult to penetrate. The Typha is confined 

 to the outer portion of the zone and has here obtained optimum 

 conditions of growth, the plants are not copious, but are tall, 

 vigorous and fruiting freely. 



n. vSwamp-shrub formation. 



6. Cornus society. 

 Facies. 



Cornus stolonifera. 



Secondary 



Rosa Carolina. 

 Sambucus canadensis. 

 Micrampeles lobata. 

 Polygonum acre. 

 Erechtites hieracifolia, 

 Scutellaria lateriflora. 

 Mentha canadensis. 



species. 



Hibiscus moscheutos. 

 Solanum dulcamara. 

 Homalocenchrus oryzoides. 

 Galium claytoni. 

 Carex lupulina. 

 Convolvulus sepium. 

 Ulmus amcricana. 



This society consists of nine Cornus stolonifera in the 

 section studied and occupies an area 20 feet broad. About 

 10 feet to the west is another Cornus stolonifera far down 

 into the Hibiscus-Typha zone ; and about 40 feet still farther west 

 is a group of 15-18 feet tall Cephalanthus occidentalis which 

 extends through the Hibiscus zone to the water's edge. Just east 

 of the eastern margin of the transect is another group of Cornus 

 with Sambucus canadensis. 



The swarnp-shrub formation does not exhibit lateral zonation 

 but alternations as it consists of isolated shrub societies of 

 which Cornus stolonifera is the principal species in one and 

 Cephalanthus occidentalis in another. The associated species 

 are grouped closely around the Cornus, most of the herbs form a 

 sparse growth in the shade of the shrubs and the Micrampeles and 

 Solanum climb over them. 



