134 Rhodora [May 
Contains many northern species, possible here only in cool, shady, 
humid situations. 
* Larix Americana, Michx. ? Rhus venenata, DC. 
* Pinus Strobus, L. Symplocarpus foetidus, Salisb. 
* Platanus occidentalis, L. Veratrum viride, Ait. 
* Betula populifolia, Ait. Osmunda regalis, L. 
* Chamaecyparis sphaeroidea, Spach. Viola cucullata, Ait. - 
* Acer rubrum, L. Equisetum sylvaticum, L. 
* Carpinus Caroliniana, Walt. Onoclea sensibilis, L. 
? Lindera Benzoin, Blume. Osmunda cinnamomea, L. 
? Ilex verticillata, Gray. ° Rhus Toxicodendron, L ` 
° I. laevigata, Gray. Sphagnum spp. 
° Nemopanthes fascicularis, Raf. 
12. SAND-Ponpd Formation. //ydrophytes. 
Habitat: ponds and slow-flowing streams throughout the sand- 
plain region with sandy bottom and little humus; plants rooted and 
usually submersed or upper leaves floating. 
Proserpinaca pectinacea, Lam. Myriophyllum tenellum, Bigel. 
Limnanthemum lacunosum, Griseb. M. ambiguum, Nutt. 
Hottonia inflata, Ell. Nuphar Kalmianum, Ait. 
Nymphaea odorata, Ait. Lobelia Dortmanna, L. 
Sagittaria teres, Wats. Brasenia peltata, Pursh. 
Naias Indica gracillima, A. Br. Eriocaulon septangulare, With. 
Orontium aquaticum, L. Lycopodium inundatum Bigelovii, 
Potamogeton Spirillus, Tuckerm. Tuck. 
13. Mup Ponp Formation.  ZZydropAyfes. 
Habitat: ponds and slow-flowing streams with bottom of clay or 
humus, often “mucky”; plants rooted and submersed or upper 
leaves floating, rarely emersed. 
Nuphar advéna, Ait. Ranunculus aquatilis trichophyllus, 
Naias flexilis, R. & S. Gray. 
Myriophyllum spicatum, L. Callitriche heterophylla, Pursh. 
Nymphaea odorata, Ait. Ranunculus multifidus, Pursh. 
Marsilia quadrifolia, L. Potamogeton crispus, L. 
Chara fragilis, Desv. P. natans, L. and other species. 
Nitella flexilis, Ag. Elodea Canadensis, Michx. 
Podostemon ceratophyllus, Michx. Vallisneria spiralis, L. 
