996 



gard to C. nigra, " seed without any down ;" and C. nigvescens is also 

 said by Babington to have the " pappus ahnost wanting," it would 

 seem that no reliance can be placed upon this character. The Mal- 

 vern plants, radiant and non-radiant, appear all to have a very short 

 but in many instances scarcely perceivable seed- down. However, 

 looking to the calyx of Smith's plant, as our specimens are quite dif- 

 ferent in that respect, until further is known on that point, so insisted 

 upon by Smith, they cannot be properly considered as C. Jacea. 



The question would now be limited to C. nigra and nigrescens, 

 if it can be truly understood what the latter is; but on the closest 

 examination of Babington and other writers, I find nothing is pro- 

 duced that will stand the test of examination, but the flowers being 

 radiant in nigrescens, and all hermaphrodite in nigra. " Flowers 

 without a radius," says Smith, as a part of the specific character of 

 nigra in E. B. ; but then in the Eng. Flora he says, " Ray describes a 

 double variety shown him by Thomas Willisel, in which the proper 

 florets of the disk were all changed to handsome radiant ones." Now 

 in what respect was this plant different from the modern C. nigres- 

 cens ? 



I find in the 'Flora Gallica' of Loiseleur Deslongchamps (1828), 

 the following attempt to discriminate the three alleged species of 

 Centaurea now under review. 



" C. Jacea. — C. caule erecto ramoso angulato, foliis lanceolato-ob- 

 longis, radicalibus subdentatis, squamis involucri interioribus scario- 

 sis, exterioribus apice serrato-ciliatis, pappo nullo, seminibus margine 

 brevissimo coronatis. 



"/3. foliis lanceolato-oblongis integerrimis. 



" y. foliis lanceolato-linearibus, inferioribus sinuato-dentatis. 



^^ C. nigra. — C. caule erecto ramoso angulato, foliis lanceolatis 

 dentatis, squamis involucri scariosis apice serrato-ciliatis, flosculis 

 omnibus sequalibus hermaphroditis, seminibus pappo piloso brevissi- 

 mo-coronatis. 



" C. nigrescens. — C. foliis radicalibus obsolete pinnatifidis, inferio- 

 ribus basi subdentatis, superioribus indivisis integerrimis, involucris 

 ciliatis, squamulis intimis scariosis." 



It must be admitted here that although there is a varied display of 

 words, nothing palpable appears worthy of discrimination, except 

 the " pappo nullo " of C. Jacea, and the " flosculis omnibus aequali- 

 bus hermaphroditis" of C. nigra. Now if, as shown by Ray, and ad- 

 mitted by modern botanists, the florets of C. nigra are not always 

 hermaphrodite, what difference remains to distinguish nigrescens 



