122 FIELD AND FOREST. 



In the same localities are obtained Panicum Crus-galli, var. hispidum, 

 and (decidedly out of place) Erecthites hieracifolia ; also a plant 

 which assuredly no one would ever look for on a salt marsh, viz. Poly- 

 gala polygama, but which seems to thrive admirably in its unwonted 

 situation, as the spikes of flowers, both cauline and radical, are much 

 larger than those produced in its common habitat. 



Polygala cruciata, Samolus Valerandi, var. Americanns, Gratiola 

 aurea and Sabbatia i gracilis are not uncommon on the borders of the 

 marshes. On the sand beaches of the sea shore occur Atriplex arenaria 

 and Erythraea spicata. Farther from the shore, in wet, sandy soil, 

 grow Eleocharis melanocarpa, Lycopodium inundation and Schwa lb ea 

 Americana; and in dry, sandy or light soil, Opuntia vulgaris, Cassia 

 chamaecrista, Crotalaria sagittalis, Lespedeza Stuvei, Spiranthes simplex 

 and Cyperus Grayii. By the edges of ponds are found Sabbatia chloroides, 

 Phragmites communis, Hydrocotyle inter rupta and Rhyncospora macro s- 

 tachya, with that rare form of the last, var. inundata. Here also is Hy- 

 drocotyle umbellata, which, however, is more common in the water 

 where it grows to the height of a foot or more according to the depth 

 of the water. 



Chrysopsis falcata abounds on the dry uplands, and by its side 

 Aster spectabilis and occasionally Aster ericoides. Here, likewise, 

 are Paspalum setaceum and Eragrostis pectinacea, but in its more south- 

 ern form, var. spectabilis. 



Among the shrubby oaks there is a form of Helianthus divaricatus 

 with very narrow leaves, and in company with it Asclepias tuberosa 

 and Asclepias obtusifolia, Habinaria tridentata, Mulgedium, lenco- 

 phozum and Lilium superbum occupy the swampy thickets; and Glau- 

 cium luteum is met with in waste grounds about dwellings. 



As a specimen of the manner in which the vegetation of middle 

 Massachusetts changes into more Southern species, a few cases may be 

 cited. The common Hydrocotyle of the interior is H. Americana; 

 here as already mentioned, H. interrupta and H. umbellata. Cassia 

 nictitans is the only species in middle Massachusetts, while E. chamae- 

 crista is never or rarely found 25 miles north of Martha's Vineyard. 

 Hudsonia tomentosa of the north, gives way to H. ericoides in these 

 islands; and Hieracium scabrum and H. cariadense surrender th e 

 ground to H. Gronovii. Linum Virginianum common through New 

 England, is here supplanted by L. striatum, which really appears to 



