164 THE PLANT LIFE OF MARYLAND 



spicuous element. The shrubs common in this association arc 

 Yaccinhim corymbosum, Sambucus canadensis, Cleihra alnifolia and 

 Pieris mariana. The woody vegetation of the wetter places is mostly 

 shrubby, including Alnus rugosa, Salix nigra, Cephalanllius occi- 

 dentali-s, Yaccinium corymbosum, Rosa Carolina, Ilex verticillata. 

 A striking feature of such associations is the large number and 

 luxuriance of the climbers.* These include various species of 

 Smilax and Vitis, Ehus radicans, Partlicnocissus quinque folia, etc. 

 In some places the tangle formed by Smilax is almost impenetrable, 

 while the other climbers ascend far into the crown of the trees. The 

 herbaceous vegetation, includes the following: 



Onoclea sensibilis 

 Alisma plantago-aquatica 

 Arisaema triphyllu m 

 Peltandra virginica 

 Saururus cernuus 

 Asclepias incarnata 

 Pentliorum sedoides 

 Polygonum arifolinm 

 Triadenum virgi nicum. 



While in the drier parts is found a typical flood-plain flora includ- 

 ing, during July and August : 



Woodivardia areolata 

 Botrycli ium ternatum 

 Boehmeria cylindrica 



♦Following the classification of Schenk (Beitriige zur Biologie und Anatoraie 

 der Lianen) these may be arranged thus: 



1. Clambering by hooked prickles — Polygonum arifolinm. Polygonum sagit- 

 tatum, Galium. 



2. Climbing by aerial roots — Rhus radicans. Tecoma radicans. 



3. Twining — Dioscorea villosa, Menispermum canadense, Celastrus scan- 

 dens, Clitoria mariana, Galactia volubUis. Falcata comosa, Apios apios. 

 Strophostyles helvola, StrophostyT.es umhellata, Vincetoxicum carolinensis, 

 Lonicera japonica, Willughbacya scandens, Convolvulus sepium, Convolvulus 

 arvensis, Ipomoea purpurea, Ipomoea hedcracea. 



4. Climbing by tendrils, consisting of 



(a) Modified leaves: Smilax rotundifolia, Vicia sativa. 

 (6) Modified shoots: Vitis sp. Partlicnocissus quinquefolia, Micram- 

 pelis loiata. 



