ATASITES AKD THYRSANTHEMA . 151/ 



distinguishing mark between them is one only. In the former 

 the bracts of the inTolucre are in several series and imbricated. 

 In the latter they form but a single series, are equal and not 

 imbricated. It is such a distinction as the most accomplished 

 synantherologists of a hundred years past and more, have 

 recognized as of generic value. 



Now, whoever shall find among the thyrsiflorous species of 

 Linnaean Tussilago, one that has imbricated involucral bracts, 

 will have the type of Thyrsanthema, Neck. 



I regret the necessity of here indicating how reckless the 

 author of the Eevisio Generum has been in his reading of 

 Necker upon Thyrsanlhema. The name, first of all, has been 

 meaningless to him. He cannot have given it a thought. He 

 assumes that to be scapose, a plant must have monocepha- 

 lous scapes. Had he read the corresponding part of the diag- 

 nosis of Petasites he would have discovered this error ; for 

 Necker says of that also, proles scaposae, indicating no differ- 

 ence. Necker is made to say of the ray flowers that they are 

 small (parvi), which would apply well enough to those of Chap- 

 latia, but Necker says those of Thyrsanthema are minute. That 

 is not parvi ; and the term minuti while not applicable to the 

 outer circle of corollas in Chaptalia is true to the letter in those 

 of certain Linnaean thyrsoid Tussilago species. Necker says of 

 the pappus of his genus, simplex pilosusve, which in the Bevisio 

 is put down as simplex pilosus. One means simple or pilose, 

 the other simple and pilose. I do not comprehend the force of 

 this part of Necker's diagnosis ; but I do know that simplex 

 pilosnsve is not the same in meaning as simplex pilosus. 



As regards Chaptalia, based as it is on Tussilago nutans, it may 

 possibly be the type of Necker's Atasites, I think ; for, as I have 

 shown already, it cannot be Gerbera, which is only an appended 

 species, not the type. It seems as if the type of Cassini's Homo- 

 gyne, that is Tussilago alpina, Linn., of which the involucre is 

 more or less imbricated, may have stood with Necker for the type 

 of Atasites. It is an European type which Necker must have 

 known well enough, while with the then new and rare T. 

 nutans of the West Indies he may have been altogether unac- 



