3<i6 • BOTANICAL GAZETTE [November 



8 



forms. 15 The lapponicum form is much less abundant and appears to 

 be merely an offshoot from T. ceratophorum. Sometimes, however, 

 especially in the northeastern part of the continent, it passes into 

 T. vulgare. 16 Fernald and Robinson (Gray's Manual, ed. 7. 865. 

 1908) evidently included some of these transitional forms in their 

 T. officinale var. palustre Blytt, from " eastern Quebec to Con- 

 necticut." At the time true T. ceratophorum was unknown to 

 them from New England (cf. Fernald, Rhodora 4:155. 1902), 

 but since then it has been discovered by Pease (Rhodora 19:111 

 and 221. 191 7) in New Hampshire; and many years before a 

 specimen was collected by Robbins. 17 The true T. officinale var. 

 palustre (T. paludosum [Scop.] Schlecht.) is not cited for North 

 America by Handel-Mazzetti. 1 



T. leiospermum Rydb., from Colorado, is found to differ from 

 the ordinary T. ceratophorum merely in having slender ecornicu- 

 late bracts and a slightly greenish tint to the brown, less muricate 

 achenes. In Handel-Mazzetti's treatment T. leiospermum 

 would belong, more precisely, with T. lapponicum. Of all the 

 many specimens that I have studied, I have found no other speci- 

 men exactly matching Rydberg's type (in Hb. N.Y.) in the 

 smoothness and color of the achenes. My failure in this respect 

 suggests that the type was merely one of the excessively numer- 

 ous forms conspicuous in this genus, which apparently often are 



x s"In der ganzen Zone der Gebirge des westlichen Nordamerika ist T. cera- 

 tophorum mit T. lapponicum durch zahlreiche Formen verbunden, die in den Merk- 

 malen der Hullblattchen Zwischenstellungen einnehmen," loc. tit. 66. 



16 Haxdel-Mazzetti (loc. cit. 84) gives an exhaustive treatment of numerous 

 forms intermediate between T. vulgare and T. paludosum, the latter being a species 

 very close to T. lapponicum. He cites none for America, however. 



f 7l have not seen this specimen. It was found in the herbarium at Berlin by 

 Handel-Mazzetti, and was determined by him as T. lapponicum. 



18 At various times some of our foremost American botanists have used the 

 names palustre and alpinum for American specimens of T. ceratophorum. The real 

 T. paludosum (Scop.) Schlecht and T. alpinum (Hoppe) Heg. and Heer, dating back 

 originally to 1772 and 1821 respectively, are not given by Handel-Mazzetti for 

 North America. While I have been unable to examine enough European material to 

 permit of definite conclusions, it would seem that the two species are too close 

 together. In any case, it appears certain that if American forms of T. ceratophorum 

 with ecorniculate bracts are to be segregated, they must be referred to T. paludosum 

 or T. alpinum, rather than to the more recent T. lapponicum. 



