1921] St. John,— Critical Revision of Hydrangea arborescens 205 



lationship is with //. arborescens L. It also lias the large cordate- 

 ovate acuminate leaves of that species, hut they are more coriaceous 

 and are densely puherulent beneath owing to the fact that all of the 

 nerves, even the smallest secondary ones, hear puherulence. This 

 variant is not found in the northern Appalachians, occurring only 

 from Ohio to Illinois and southward to Oklahoma, Tennessee, and 

 Georgia. As in the previous case there are intermediate specimens. 

 Such a one as that from Kennesaw Mt., Georgia, May TO, 1885, 

 R. N. Larrabee has the leaf form of var. oblonga hut the pubescence 

 of the more western pubescent phut. Then there are plants with 

 the pubescence so sparse on the secondary nerves, that it becomes a 

 matter of fine judgment whether or not the plant should he con- 

 sidered //. arborescens L., or the pubescent plant under discussion. 

 Again, this plant seems to be properly treated as a variety (if //. 

 arborescens \j. Mr. Charles C. Deam, who has recently collected this 

 variety in Indiana, has noticed that it differed from the essentially' 

 glabrous //. arborescens L., and has called my attention to it. Con- 

 sequently I take pleasure in dedicating this new variety to him. 



There is a sterile or radiant form of each one of these three plants, 

 although they have been found but a few times in the wild slate. 

 Their rarity is well brought out by a note on a specimen of //. arhor- 

 escens L., var. oblonga T. & G. in the Gray Herbarium collected at 

 Bedford, Virginia, June 25, 1871, by A. H. Curtiss. He writes, "I 

 have for seven years in X. & S. Va. searched for radiant flowers on 

 this spfecies] but never till this year found them & these on a single 

 bush. So I conclude they are of very rare occurrence." This speci- 

 men has only a few of its marginal flowers radiant and would not in 

 the present classification be considered as of the radiant form, which 

 has all of its flowers sterile arid radiant. In classifying these showy 

 forms it is necessary to give one new name and to make one new 

 combination. 



pubescence characteristic of ll. radiata Walt., except for the color. A careful exam- 

 ination of these two sheets shows that the leaves seen from above have the great 

 blotches of brownish or blackish color which are characteristic of poorly dried speci- 

 mens or those dried under unfavorable conditions. Also both specimens have been 

 poisoned with a solution of corrosive sublimate as is shown by the yellowish stains on 

 the sheets. Consequently, it seems evident to the writer that the gray color of the 

 pubescence is due to the poor drying and the poisoning and that these two specimens 

 are without question //. radiata Walt. The remaining one, Scribner, July, 1894, 

 of the five specimens on which II. dnerra Small was based has not been seen by the 

 author. 



