THISTLE FAMILY. ; 798 
Silphium asperrimum Hook. Comp. Bot. Mag.1:99, 1835. 
2 ROUGH-LEAF ROSINWEED. 
Silphium radula Nutt. Trans. Am. Phil. Soc. 7: 341. 1884. 
S. scaberrimum var. Torr. & Gray, FI.N. A. 2: 279." 18.12. 
Gray, Syn. FI. N. A.1, pt.2:240. Coulter, Contr. Nat. Herb. 2: 205. 
Carolinian and Louisianian areas. Southern Arkansas, Texas, and Louisiana, 
ALABAMA: Mountain region. Grassy glades; dry borders of fields. Clay County, 
Mount Olive, 1,500 feet altitude. July, August; frequent. 
Type locality: ‘‘ Covington,” Louisiana (Drummond). 
Herb. Geol. Surv. Herb. Mohr. 
Silphium scaberrimum Ell.8k.2:466. 1824. ScaBRous ROSINWEED. 
Ell. Sk. lc. Gray, Syn. VILN. A.1, pt.2: 240, Coulter, Contr. Nat. Herb. 2 : 205. 
o Carolinian and Louisianian areas. Western Georgia to Louisiana, Arkansas, and 
exas. 
ALABAMA: Central prairies. Upper division Coast Pine belt. Prairies, Wilcox 
County? (Buckley). Monroe County, Claiborne. Lee County, Anburn (Baker § 
Earle). Etowah County, Gadsden (G. 2. Vasey). July; infrequent. 
Type locality: ‘‘ Grows in the western districts of Georgia.” 
Herb. Geol. Surv. Herb. Mohr. 
Silphium mobrii Small, Bull. Torr. Bot. Club, 24:493. 1897. Monr’s RoSINWEED. 
Perennial, coarse, very hispid throughout with shaggy hairs. Stem erect, 2} to 34 
ft. tall, simple below, branched above, tinely-channeled in age; leaves alternate, 
ovate-lanceolate, or narrowly ovate-lanceolate, or normally ovate, 2 to 6 in. loug, 
acuminate at the apex, remotely serrate with prominenv teeth, except near the 
base or apex, sessile or nearly so; heads 14 to 13 in. broad, pediceled; involucres 
broadly campanulate, the bracts lanceolate to ovate-lanceolate, 4 to 7 lines long, 
acute or somewhat acuminate; corollas about 4 mm. long, the segments ovate, rather 
obtuse; rays yellow, elliptic-oblong, 5 to 7 lines long, undulately 3-toothed at the 
apex; achenes obovate, more or less constricted at both ends, about 3 lines long, 
winged. PLATE XII. 
Exposed rocky declivities. Cullman County. 
A very distinct species of the much confused genus Silphium, related to what I 
understand as 8. asperrimum Hook., hitherto called 8. scaberrimum. It can easily be 
distinguished hy the copious shaggy pubescence which clothes the foliage up to the 
flowers. The peculiarly toothed leaves with their less rounded bases and the smaller 
heads with their narrow bracts and shorter rays are additional diagnostic charac- 
ters. 
“The species is named in honor.of Dr. Charles Mohr.” 
Carolinian area. Tennessee (Gattinger). 
ALABAMA: Mountain region. Exposed rocky declivities. Cullman County. Octo- 
ber, 1894. Rare. 
Type locality: ‘In dry or rocky soil, Cullman, Alabama, October, 1885.” 
Herb. Geol. Surv. Herb. Mokr. 
Silphium gatesii sp. nov. 
Stem 2} to 8 feet high, terete, hispid-pilose throughout with long white hairs jointed 
above the inflated papillose base, above the middle more or less covered by short flat 
tawny hairs forming on the upper part of the stem and the branches a close tomen- 
tum; leaves all alternate, acutish, scabrous above, paler and less harsh beneath, the 
yadical and lower cauline leaves 6 to 8 inches long, } to } inch wide, narrowed at the 
base into a slender winged petiole one-third of the length of the sparsely sinuate- 
dentate leaf blade, the upper sessile with a more or less cordate base, sparsely den- 
ticulate or entire; corymbose branches erect-spreading; flowering heads more or less 
numerous, large; involucral bracts tomentose-hairy on the outside, scabrous-hirsute 
above, hispidulons-ciliate, oblong-acute, the outer longer then the disk; rays nearly 
14 inches long, golden yellow; achenes obovate, rather oblong, narrow-winged, 
slightly emarginate, teeth minute or wanting. PLATE XIII. 
Resembles narrow-leaved forms of S. asteriscus, from which it is distinguished at 
once by the peculiar pubescence, the thinner narrower leaves, and the oblong-ovate 
achenes almost or entirely destitute of teeth. There isa form with broad leaves and 
wing. 
Named in commemoration of Hezekiah Gates of Mobile, one of the earliest contrib- 
utors of Alabama plants to Torrey and Gray’s Flora of North America, to whom Dr, 
Gray dedicated his genus Gatesia, a name found untenable and lately replaced by 
Yatesia. 
Carolinian area. 
