374 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



where Asler puniceus and the like spread so vigorously. For comparison with A. chor- 

 alis, see that species. 



While a shale is not a "schist" in a geological sense, schistosus, as a Latin word, 

 describes with sufficient accuracy the substratum upon which this species grows, and 

 hence may well serve as its name. 



Silphium reniforme Rat; Nutt. Trans. Amer. Phil. Soc. n. ser. 7: 342. 1841. 



This plant, referred in Small's Flora to North Carolina, proves to be a locally com- 

 mon Virginia species also. I first met it yi 1903 on shale ground about a mile from 

 Eagle Rock, Botetourt County. In 1906 and 1907 I found it common about Millboro, 

 Bath County, on whale, sometimes on shale clay. The largest specimens seen were on 

 the latter in a golden-rod and aster field, where it exceeded a man's head in height. 

 It was seen also from a train on the Chesapeake and Ohio Railroad at a point between 

 Covington and Allegheny. I think I saw a specimen on siliceous rock near Millboro, 

 but it is doubtful if it ever wanders far from an argillaceous base. 



The description is as in Small's Flora. The species is an obvious ally of S. terebin- 

 thinaceum, from which it differs in its lower leaves being spreading instead of erect, 

 much smaller, and usually as broad as long or broader. 



Helianthus laevigatus reindutus Steele, subsp. nov. 



Often small but becoming fully as high as the type, more disposed to branch and 

 sometimes quite bushy; lower internodes shortened, often several only 2 to 3 cm., or 

 in stronger plants 4 to 5 cm. long, at least one or two of the lowest more or less densely 

 papillose-hirsute, decreasingly so commonly up to the fourth or fifth; lower surface 

 of the lower leaves, often as far up aa the branches, very scabrous, higher becoming 

 smooth, the upper surface little if at all roughened. 



Type in the U. S. National Herbarium, no. 494565, collected by E. S. Steele 

 at Millboro, Bath County, Virginia, September 1-17, 1906. On hills of crumbling 

 shale and shale cliffs, common. Thirteen specimens, collected different days, were 

 preserved . 



This very pronounced form seems to prevail to the exclusion of the type on the 

 shales of Bath County. A specimen clearly the same was obtained from the shale at 

 the base of Great North Mountain, Augusta Springs, Augusta County, in 1908. A 

 specimen collected by Heller and Ilalbach (no. 1185) from Elliott's Knob (Great North 

 Mountain), the substratum not stated, haa the lower surface of the leaves considerably 

 scabrous. Other material collected by myself on siliceous ground of the same region 

 ia smooth. 



Helianthus laevigatus is a familiar plant among the brush on stony ground of tin 

 Virginia mountains. As seen by me, it ia not usually much branched, nor is the 

 subspecies by any means always so. The internodes should be long, except ono or 

 two of the lowest. The stem should be essentially smooth, aa also the leaves, except 

 the margin. The tegulea in both the type and the subspecies are very frequently 

 prolonged into a slender rigid, revolute-margined, almost acicular tip. 



Tho supposition is at least plausible that this subtype is a direct transformation of 

 E. laevigatus, due to the special influences of the shale substratum. I hazard theguess 

 that in spreading over the shale where the plant covering is exceedingly imperfect 

 it found an indument on the base of the stem and the lower surface of the leaves 

 advantageous as a protection from the reflected light and heat. In other situations, 

 the vegetation ia generally well closed up (except in deep shade, where this plant 

 does not grow) and the want was not equally felt. 



