BRITISH HIEIUCIA. 33 



Involucres broadly ovate or sub-turbinate at the base. Phylla- 

 lies incumbent in bud, linear, attenuate, more or less acuminate ; 

 white at the points, with floccose down, especially in the young 

 bud. Florets golden yellow, obscurely pilose at the tips. 

 Styles yellow, sometimes slightly clothed externally with very 

 minute darkish hairs. 



This species differs from its ally S. nigrescens in having evenly 

 and remotely dentate root-leaves, a linear elongated stem-leaf, 

 narrower phyllaiies, and yellowish (never fuliginous) styles. From 

 H. lingulatum, to which it is also closely allied, it differs strongly 

 in its stem-leaves, in its floccose acuminate phyUaries, which are 

 incumbent and not porrect in bud, and in its nearly yellow styles. 



The buds of S. senescens when in a very young state, are con- 

 spicuously marked by the densely floccose tips of the undeveloped 

 phyllaries, giving the effect of a white spot in the centre. M. nig- 

 rescens and some other species also exhibit this feature, but not to 

 the same degree. All the distinguishing characters of H, senescens 

 remain Tmchanged under cultivation, when the plant has been raised 

 firom seed for many years successively. Under these circumstances 

 it flowers abundantly a second time, in the 10th month, many weeks 

 after H. nigrescens has done flowering. 



Although I have no hesitation in regarding this plant as identical 

 with the S. atratum v. ramulosum of Fries, yet I am equally 

 satisfied that it is specifically distinct from specimens regarded by 

 that author as " S. atratum" (which must be referred to S. ehry- 

 santhum v. microcephalumj and to S. nigrescens. This leads me to 

 believe that the character of S- atratum in Fries' Symb. p. 105, 

 unites that of my H. senescens {" H. atratum v. ramulosum" Fries) 

 with extreme forms of other distinct species. H. atratum is described 

 as having " one or few heads : " H. senescens is, so far as I have 

 observed, never truly monocephalous. * 



* A Plant usually tearing few or many heads, may be so reduced by situa- 

 tion, &c. as only to develope one head ; but where this is the case, the minute 

 incipient axillary buds prove that it is not a truly " monwephaloas " species. 



B 



