30 BROOKLYN BOTANIC GARDEN MEMOIRS 



These ten species make up the bulk of the vegetation between the 

 lowest part, occupied exclusively by Eleocharis obtusa, and the band of 

 vegetation nearest the margin. 



This marginal zone of vegetation occupies ground that, while well 

 below the surrounding Downs, is high enough so that it is only covered 

 by water for a short time in the spring. The plants here, therefore, do 

 not suffer for water, nor are they smothered by it, as happens frequently 

 in some kettleholes with uneven bottoms, or other conditions that permit 

 too much standing water. 



The vegetation of this marginal zone can best be shown by pointing 

 out the dominant species toward the contact with the open Downs on the 

 one hand, and toward the center of the kettlehole on the other, where it 

 touches the zone for which the species have already been listed. In the 

 following list of species the first and last are dominant nearest the inner 

 and outer edges of the zone respectively. The others are arranged in order 

 of frequency, reading from the top down for those nearest the inner edge 

 of this marginal zone, and from the bottom up for those nearest the Downs. 

 Toward the middle of the list are those species that are pretty commonly 

 distributed all through this marginal zone. 

 Euthamia tenuifolia 



Dominant in that part of the marginal zone nearest the center of 

 the kettlehole. 

 Steironema lanceolatum 

 Often appearing dominant in midsummer from its wealth of con- 

 spicuous yellow flowers. 

 Gratiola aurea 

 Viola lanceolata 



Very often making large patches where it is locallv dominant, 

 but general and common through the lower part of the marginal 

 zone. 

 Eleocharis tenuis 

 Rhexia virginica 

 Athyrium thelypteroides 

 Eupatorium perfoliatum 



One of the tallest herbs in the kettlehole. 

 Xyris flexuosa 

 Hypericum boreale 

 Juncus acuminatus 

 Stachys hyssopifolia 



Nearest the form known as 5. atlantica 



