Tab. 6918. 



silphium albifloeum. 



Native of Texas. 



Nat. Ord. Composite. — Tribe Helianthoidej:. 

 Genus Silphium, Linn.; {Benth. et Hook.f. Gen. PI. vol. ii. p. 350.) 



Silphium alhiflorum ,- robustum, scabridum, caule tereti simpliei, foliis alternis 

 petiolatis arabitu late ovatis pinnatifidis v. bipinnatifidis rigidis, lobis linearibus 

 acutis v. pungentibus reticulatim venosis, floralibus linearibus capitatis 

 amplis sessilibus v. crasse pedunculatis, involucri scabridi bracteis erasse 

 coriaceis e basi late ovata in rostrum recurvum productis infimis subfoliacois, 

 floribus radii pollicaribus pallide stramineis, disci eoncoloribus, acheniis pubes- 

 eentibus, alis superne productis. 



S. albiflorurn, A. Gray in Proc. Amer. Acad. vol. xix. p. 4, and Synopt. Flora 

 of N. Amer. vol. i. pt. ii. p. 242. 



This is one of two species of the North American genus 

 Silphium which Gray includes under the " Compass Plants," 

 and of which the original, 8. laciniatum, L., was figured at 

 Plate 6534 of this work. S. albiflorurn is not nearly so 

 handsome a plant as 8. laciniatum, being comparatively a 

 dwarf, of robust rigid habit, with nearly white flowers. The 

 cultivated specimens are much less scabrid, as might be 

 expected, than the native, and have longer points to the 

 involucral bracts, giving a squarrose look to the unopened 

 heads ; these latter, too, are much longer peduncled, and 

 indeed Mr. Thompson sends a specimen in which the 

 stem is terminated by a solitary long-peduncled flower- 

 head. There is a further difference in the achenes ; those 

 of the native plant have the wings produced upwards into 

 somewhat triangular teeth which are often adnate to a pair 

 of subulate and more or less projecting rigid awns ; in 

 the garden plant the upward continuation of the wings are 

 rounded at the tips, and there are no awns, in a young 

 state at any rate. 



I am indebted for living specimens of this very interesting 

 plant to my old and valued correspondent, Mr. Thompson, 

 of Ipswich, who has for. so many years contributed objects 

 of value and interest to this work ; he sent it in September 



i\eb. 1st, 18S7. 



