SO THE PLANT LIFE OF MARYLAND 



alopecuroid.es, Xyris fimbriata, Xerophyllum asphodeloides, Oyro- 

 theca capitata, Arenaria carolinana, Drosera filiformis, Hudsonia 

 ericoides, Dendrum buxifolium and Pyxidanthera barbulaia. 



The Midland Zone. 



The Midland Zone possesses a rich flora, a large part of which 

 ranges, as already stated, from Ontario and New England south to 

 Georgia and Alabama. There are apparently, however, no common 

 plants which are confined to the Midland Zone in Maryland, for 

 those species which do not range south-east into the Coastal Zone do 

 range wesl into the Mountain Zone, while those not ranging into the 

 Mountain Zone are all found in the Coastal Zone. It is only in the 

 Midland Zone that the limestone plants Asplenium ruta-muraria and 

 Cystopteris bulhifera and the serpentine plant Talinum teretifolium 

 have been found. Rhus <irt>i>iulicti . too, has been observed only in 

 l he Midland Zone, and appears to he more abundant on limestone. 



Under present-day conditions there appears to he a small element 

 of the Midland flora which occurs in the foot hills of Allegany 

 County and in the Blue Ridge and Catoctin Mountains, which is 

 mil found in the Lower Midland District. That these species may 

 have occurred in the Lower Midland District when the vegetation 

 of Maryland was in its virgin state appears probable from the rare 

 occurrence there, in favorable habitats, of species which are asso- 

 ciated with them in the Upper Midland District. Among these 

 plants are the following: Pinus pungens, Oorylus rostrata, Hittnulus 

 lupulus, Adlumia fungosa, Spiraea corymbosa, Rubus odoratus, Acer 

 nigrum, Acer spicatum and Eupatorium sessilifolium. 



Along the Potomac River, and particularly in the vicinity of the 

 Great Falls, are found a number of species which are known else- 

 where only from the Upper Midland District or the Mountain Zone. 

 These are: Uniola latifolia, Hystrix hystrix, Allium cernuum, 

 Erythronium albidum, Vagnera siellaia, Parietaria pennsylvanica, 

 A conitum uncinatum ( tide Ward ), 7'rautveUeria carolinensisj Jeffer- 

 sonia diphylla, Chaerophyllum procumbens, Erigenia bulbosa, Phlor 

 subulata and Viburnum pubescens. 



