366 BOTANICAL GAZETTE [NOVEMBER 
fox-grass comes the Puccinellia, which occurs in scattered dense 
radiating clumps, like a bunch-grass, in part here and there 
amongst the fox-grass, from which it is distinguished by its 
lighter color, and in part as scattered clumps on new marsh fol- 
lowing the Statice in its advance. The Festuca is less common 
but grows somewhat after the same manner, as indeed does the 
Juncus or black grass. Triglochin occurs scattered among the 
other members, and seems equally at home here and in the fresh- 
water associations later to be noted, and Glaux is likewise scat- 
tered. Hordeum comes in only when the association reaches 
its greatest development on the highest marsh, and it occurs 
often as a band on the dikes above the other members. Scat- 
tered plants of Spartina stricta, Salicornia, Suaeda and Atriplex 
also occur as visitors, especially with the Statice. When this 
association reaches its greatest development on the highest 
marsh, it consists of a dense closed growth of all of the forms 
intermingled, and this constitutes the characteristic mature marsh. 
Upon it then develops the Hordeum (fig. 73). In this condi- 
tion it can apparently build itself somewhat above the general 
marsh level, in part through the aid of the mud held by the 
plants when brought to them by the occasional extreme tides, 
and in part from the decay of their own members; and upon the 
higher places of this kind come in the occasional visitors, the 
broadleaf (Spartina cynosuroides), the couch (Agropyrum vulgare) ,. 
Potentilla anserina, goldenrods, and others. But these represent 
the highest development; so far as any parts of the marshes _ 
now show, no woody vegetation ever gains a foothold. 
It is plain that within this association while the members 
occur variously intermingled, there is some differentiation of 
position. Thus, typically the marginal member is the Statice, 
which is followed by the Plantago and the Puccinellia, while 
the fox-grass comes next, then the Festuca, Juncus, Triglochin, 
Glaux, and finally the Hordeum. Further, the marginal members 
tend to some extent to lessen, or even disappear towards the 
central or higher parts. This tendency to a zonal arrangement 
shows itself with great clearness upon the outer faces of the 
dikes, where there is usually a band of Statice at the lower angle, 
