46 UNIVERSITY OF MISSOURI STUDIES [1S8 



phyllum Virginicum and H. appendiculatum, or Galium Apa- 

 rine, form an almost unmixed community. The wild ginger 

 {Asarum anibiguum) also forms dense patches on rich lower 

 slopes. Especially noteworthy is the liliaceous element. A 

 line of tall Solomon's seals, true and false (Polygonatum spp., 

 and Smilacina spp.), nods over the stream at the verge of the 

 bank. Uvularia grandiflora is also frequent. Certain grasses, 

 notably Uniola latifolia, Brachyelytrum aristatuni, Bromus 

 purgans, and the various species of Elymus, have a similar 

 nodding habit. 



a. Praevernales. 



The prevernal ravine plants commonly possess bulbs, bulb- 

 like corms, thickened rootstocks, or tubers. Sanguinaria Cana- 

 densis, Claytonia Virginica, Erythronium albidum, Isopyrum 

 hiternatum, Dicentra Cucullaria, Dentaria laciniata, Erigenia 

 bulbosa, Viola papilionacea, Collinsia verna, and Phlox divaricata 

 are common. 



b. Vernales. 



The vernal ravine herbs consist mainly of plants that ma- 

 ture their fruit in late summer or autumn. Typical species are : 

 Arisaema atrorubens Cypripedium parviflorum 



Uvularia grandiflora (very rare) 



Smilacina stellata (rare) Asarum ambiguum 



S. racemosa Thalictrum purpurascens 



Polygonatum biflorum Leontice thalictroides 



P. commutatum 



c. Praeaestivales. 



The preaestival flora consists mainly of Galium Aparine, 

 Hydrophyllum Virginicum, H. appendiculatum, and Ellisia 

 Nyctelea. 



d. Aestivales. 



The aestival flora is not well marked. Agrimonia striata 

 and A. mollis, Zisia aurea, Cryptotaenia Canadensis, and Sani- 



