161 



On Long Island what species grow only north or south of the 

 " backbone " of the island ? (A similar inquiry could be made 

 relative to the terminal moraine in New Jersey and Pennsylvania.) 



What species occurring at similar altitudes and latitudes on the 

 mainland are wanting on Long Island, and why ? What species 

 native in Suffolk County do not grow in Nassau or Queens, and 

 vice versa ? To what families and habitats do such species mostly 

 belong ? 



Why do a good many pine-barren plants occur in the eastern 

 half of Long Island and not in the western half? 



What native species and genera in our vicinity are common to 

 the Pacific slope ? the West Indies ? South America ? Europe ? 

 Asia? 



What proportion are endemic to Eastern North America ? 



What proportion of the species in our local flora, or in the 

 northeastern states, were known to Linnaeus ? Michaux? Pursh ? 

 Torrey & Gray ? 



What proportion still bear the names that these authors used 

 for them ? 



What species have their type-localities in this vicinity (or in 

 any limited area, such as New Jersey) ? 



What new genera (if any) were discovered in the northeastern 

 United States during the 19th century? 



What geographical names in this vicinity were derived from 

 native plants ? 



What are the natural (or prehistoric) habitats in this vicinity of 

 Pimis virginiana, P. Strobus, Jmiiperns virginiana, J. communis, 

 Acorits Calamus, Spatliyema foctida, Jiinctis effusus,/. tenuis, An- 

 dropogon scoparius, Panicum virgaUun, Scirpus atrovirens, Carex 

 lurida, Juncoides campestre, Smilax rotundifolia, Juglans nigra, 

 Carpinus caroliniana, Betula populifolia, Quercus alba, Q. palus- 

 tris, Q. Phellos, Morns rubra, Ulmus americana, Celtis occidcn- 

 talis. Polygonum pennsylvanicum, Polygonella articidata, Clayionia 

 virginica, Liriodendron, Raiiunculus abortivus, Menispermum, Sas- 

 safras, Liquidambar, Rubus occidcntalis, Potcntilla canadensis, 

 Prunus scrotina. Cassia marilandica, Gleditschia, Robinia Pscud- 

 acacih, Acalypha virginica, Rhus hirta, R. glabra. Ilex opaca, 



