3 1 4 
The Ohio Naturalist. 
[Vol. VIII, No. 6, 
here consists, then, of dissophytic annuals, constituting as de¬ 
termined by the facies the Cakile-Xanthium Formation: 
Facies: Cakile edentula, 
Xanthium communeX 
Polanisia graveolens. 
Principal Species: Siropliostyles helvola. 
Secondary Species: 
Cenchrus tribuloides , Euphorbia polygonijolia. 
There is considerable alternation in this formation, the 
Cakile edentula Consocies occupying the more exposed Lake 
beach, while the Xanthium commune Consocies is best seen in 
places along the less exposed Bay beach. Polanisia is more 
indifferent as to its location, it occurring sometimes alone but 
more usually indiscriminately mixed with the other facies. 
The Sand Plain—The Artemisia-Panicum Formation. 
Where the continuity of the outward growth of the land form 
of the peninsula has not been broken by the formation of a sand 
ridge it is often difficult to draw the line between the upper limit 
of the Drift Beach and the lower limit of the Sand Plain. 17 Upon 
the burial of the driftwood wffiieh accumulates in the upper part 
of the Drift Beach by the indrifting of sand, the land becomes 
sufficiently elevated to form a slightly different habitat which is, 
of course, free from the mechanical violence of the waves at any 
time, other than at very rare periods. The habitat thus may 
support a vegetation of annuals, biennials, and perennials, de¬ 
pending simply upon their ability to cope with the otherwise severe 
conditions of environment. 
The vegetation of the Sand Plain may, from its facies, be 
designated as the Artemisia-Panicum Formation. It has essen¬ 
tially the following structure: 
Facies: Artemisia caudata, 
Panicum virgatum. 
Principal Species: 
Salix interior & var. wheeleri. 
Arenaria serpyllifolia, 
Arabis lyrata. 
16. This species is probably best denominated as Xanthium commune , 
rather than as X. canadense, as given in the Flora of Cedar Point.—W. A. 
Kellerman and O. E. Jennings. Ohio Nat. 4 : 186-190. June, 1904. 
17. Synonymous habitats with this are Macmillan’s “Back Strand” 
(Lake of the Woods); Cowles’ “Upper Beach” (Lake Michigan); and 
Ganong’s “Grass Plain” (Miscou Island). 
