MARYLAND WEATHER SERVICE 301 



lin, Harford County, Gaithersburg, Montgomery County, the bar- 

 rens of Elk Ridge in Washington County and the steep shale slopes 

 to the northeast of Cumberland in Allegany County, are ill adapted 

 to any crop. In the southern Eastern Shore the occurrence of a 

 high percentage of Hickory in a deciduous or mixed forest may be 

 taken as an indication of a deep loam soil, and points to the neigh- 

 boring soils as having a high value as wheat land. On the other 

 hand the Elkton clay of the Eastern Shore, characterized by White 

 Oak, Loblolly Pine, Holly, etc., (see p. 109) is valuable wheat 

 land, although not capable of producing as high yields as are got 

 on the loam soils. In the upper Eastern Shore the bulk of the 

 upland is well adapted for the prodiiction of high yields of wheat, 

 which, together with the high percentage of Hickory in the oldest 

 forests there, is in accord with the conditions in the southern East- 

 ern Shore. The occurrence of the Tulip Tree on the Eastern Shore 

 is an indication of soil in which the moisture content is too high 

 for cultivation, although it is an infrequent tree in the upland for- 

 ests of the tipper counties. In the Midland Zone the occurrence of 

 a high percentage of Hickory is of no significance in connection 

 with the adaptability of the soil to wheat, and the presence of the 

 Tulip Tree is quite equivalent to that of the Hickory on the Eastern 

 Shore. 



The fact that the majority of our native and introduced weeds 

 are plants with a high degree of adaptability to different atmospheric 

 and soil conditions and excellent capacities for seed dispersal makes 

 them of only very general value in indicating the agricultural ca- 

 pabilities of soils. The weed flora of a field is much less a function 

 of its soil character than it is of the source from which it was seeded, 

 the surface conditions in which the soil was left, and the length of 

 time that has elapsed since it was disturbed. In Part III. some 

 facts have been brought out with regard to the difference exhibited 

 by abandoned fields in successive years. 



Such weeds as the White Daisy (Chrysanthemum leucanthemum) , 

 the Wild Carrot (Daucus carota) and the Narrow-leaved Plantain 

 (Plantago lanceolata) are omnipresent throughout Maryland on soils 

 of the widest diversity, in fields and waste grounds, both in open 

 and shaded situations, and their catholicitv of habitat is character- 



