MICHIGAN ACADEMY OF SCIENCE. 137 



the late Rev. Mr. Currie of Thedford reports having seen one or two speci- 

 mens of the species near that place. Salix gluacophylla is abundant on the 

 upper beach and dunes and is a substantial sand i)inder. Shepherdia cana- 

 densis is also very abundant in places, and many herbaceous plants, a few 

 not seen elsewhere, also find a congenial home here. On the shaded sides 

 of high dunes are Oryzopsis racemosa and Carex ehurnea, and in the drifting 

 sands, bugseed grows in great abundance. In places Buchnera americana, 

 Aster ptarmicoides, and Viola arenaria are frequent. 



In a few places on the delta islands, xerophytic conditions prevail. Within 

 a small area on Squirrel Island, the following assemblage of plants was ob- 

 served: Liatris scariosa, Hieracium longipilum, butterfly-weed, wild lupine, 

 Lespedeza capitata, Ceanothus americanus, Gentiana pubenda, Bucknera ameri- 

 cana, Stipa comata, Andropogon scoparius, Gerar^ia skinneriana. and G. par- 

 vifolia. 



LOCAL AND INTRODUCED SPECIES. 



Some localities are noted for the occurrence of one or more species seldom 

 seen or at least not noticed elsewhere. Not far from the dunes fine speci- 

 mens of the tulip tree are noticed and the butternut is not uncommon. In 

 the wooded river flood ])lains. many large trees of the black walnut still 

 exist. At the north end of Walpole Island, the scarlet painted cup and 

 Cerastrium arvense ohlongi folium are abundant, the latter not noticed in any 

 other place. About the middle of the north half of the same island, several 

 places are thickly covered with Silphium terebinthinaceum, long ago reported 

 by Prof. John Macoun. On the bank of the Aux Sable River, Mr. Newton 

 Tripp of Forest found Cacalia tuberosa and Astragalus neglectus, both rare 

 for this region. In and about a pond north of Sarnia, Utricularia resupinata 

 is very plentiful. 



The changes brought about by the destruction of the native flora are 

 accompanied b,v the introduction of numerous species. At Point Edward, 

 where the Grand Trunk railway formerly' crossed the St. Clair River into 

 Michigan, the following introduced plants have been well established for a 

 number of years on sandy ground and in streets and waste places: Datura 

 stramonium, D. tatula, Ambrosia psilostachya, Amaronthus blitoides, Russian 

 thistle. Catnip, Solanum carolinense, Euphorbia hicida, Arte»iisia rulgaris, 

 A. pontica, A. frigida, Echium vulgare, Ribes aiireum, Matrimony vine, 

 Linaria vulgaris, L. minor, Verbena striata, V. bracteosa, Cycloloma atriplici- 

 folium, Chenopodium botrys, Thlaspi arvense, Onopordum acanthium, Bromus 

 brizaeformis, B. tectorum, Sisymbrium altissimum, Petalostemon purpureum 

 and others. 



Scientific names are according to Gray's New Manual of Botany, Illus- 

 trated. 



LIST OF SPECIES. 



Polypodiace^e. Fern Family. 



Phegopteris dryopteris (L.) Fee, Oak Fern. — Occasional in rich woods. 



Adiantum pedatum L. Maidenhair — Frequent in damp woods and 

 thickets. 



Pteris aquilina L. Common Brake. — Common both on damp and dry 

 ground. 



Woodwardia virginica (L.) Sm. Chain Fern. — Occasional on low and marshy 

 ground. Newton Tri[)p. 



