MARYLAND WEATHER SERVICE 225 



The ground slopes rapidly from the low area, and in a short dis- 

 tance becomes so dry that the Bear Oak and the Chinquapin find 

 suitable habitats, and other species of oak, such as the White Oak, 

 the Swamp Oak, Post Oak, the Black Oak and the Chestnut Oak 

 also grow close to the wet ground, but on the drier hillside. The 

 only specimen of the Scrub-Chestnut Oak (Qaercus prinoides) seen 

 in this section of the state was found along the road at the top of the 

 slope of the valley where this swamp was located. The condi- 

 tions were very dry, the habitat was fully exposed to the south 

 winds and full sun; being the elevated bank of a sandy and rocky 

 road. 



To the east of the Ridge, the same series of lower ridges or long 

 hills occur, and among them are similar localities with moist soil 

 in which the plant growth is slightly different from that of the 

 areas already mentioned. Osmunda regalis is among the plants not 

 previously noted, and the presence of the Elder (Sambucus cana- 

 densis) is a conspicuous feature of the low ground vegetation. 

 Thalictrum dioicum is in good bloom in early July, and Seri- 

 cocarpus linifolius is also in flower. One of the species of Milk- 

 weed, Asdepias pidchra, is common in the moist situations, and in 

 the thickets the two Haws (Viburnum dentatum and Viburnum 

 prunifolium) are associated with the Choke-berry (Aronia arbuti- 

 folia). Under the branches of the thicket shrubs Spathyema foetida 

 and Orontium aquaticum are occasional, and in the more exposed 

 spots with abundant moisture, Aletris farinosa, Sagittaria latifolia, 

 Rhexia mariana, and Polygala viridescens occur. 



The sides of the ridges are often steep and therefore well drained 

 or even very dry especially if there has been recent cutting of tim- 

 ber. The conditions then are extremely hard upon vegetation, since 

 fire follows in so large a number of instances that it seems almost 

 the usual sequence. 



Under the unfavorable conditions of sudden increase of strong 

 sunlight, greater circulation of drying winds, and the severe me- 

 chanical injury clue to careless felling of the trees, only the most 

 hardy of the original plants can survive, and these have to combat 

 under a disadvantage, the hardy invaders from roadsides, or other 

 waste places, where the conditions are even more severe. 



