1906] Fernald,— Anomalous Plants of Tiarella and Mitella 91 



in anthesis/ indicates, in connection with its other characters, that the 

 anomalous plant from P>1 River is a probable hybrid between those 

 two species, both of which abound in the St. John Valley. 



Another plant which seems to be a hybrid of Tiarella cordifolia and 

 a species of Mitella was noted by Dr. Gray- in 1886, although that fact 

 seems to have been overlooked in two recent extended publications on 

 the North American Saxifragaceae,^ where another probable hybrid, 

 between Mitella diphi/lla and M. nuda, is recognized by both authors, 

 by Dr. Rydberg as M. intermedia Bruhin; by Dr. Rosendahl as M. 

 diphylla, forma intermedia, with the suggestion as already made by 

 Mr. Bruhin in a letter to Dr. Ciray that the plant is a hybrid. The plant 

 referred to by Dr. Gray in the Bulletin of the Torrey Botanical Club 

 has the aspect of a small-flowered Tiarella with unusually rounded 

 leaves, and the small petals are more or less lacerated. This plant 

 which was thought by Dr. Gray to be a possible hybrid of Tiarella 

 cordifolia and Mitella diphylla is represented by two sheets in the Gray 

 Herbarium, one from Williamstown, Massachusetts (coll. Sanborn 

 Tenney), the other from Wilton, New Hampshire (coll. M. A. C. Liver- 

 more) . 



Since the parents of these suj)posed hybrids are all common in many 

 portions of New England and eastern Canada it is hoped that the above 

 notes will stimulate those who have opportunity to watch them in 

 the field to observe whether this tendency to inter-generic hybrids is 

 more common than we supjjose, and, more important still, whether 

 these plants, as seems to be the case, are always sterile. 



Another plant which should be sought by northeastern botanists is 

 Mitella prostrata Michx. discovered by Michaux more than a century 

 ago near Lake Champlain, but so far as we know not since detected. 

 This- was originally described as 



M. "PRCSTRATA. ^I. radice repente; caulibus prostratis, alterne 

 foliosis: foliis rotundato-cordatis, subacutis, obtuse sublobatis. 



Hat), ad fines meridionales Canadae."^ 



This plant was taken by Torrey and Gray to be a peculiar extreme 



1 Tiarella cordifolia flowers regularly in late spring and early summer, and rarely if 

 ever produces autumnal flowers. Mitella nuda. on the other hand, is inclined to pro- 

 duce flowers somewhat erratically throughout the summer and autumn, though its sea- 

 son of profuse blooming is in late spring and early summer. 



2 A. Gray, Bull. Torr. Bot. CI. xiii, 85 (as insert), 100 (1886). 



3 Rydberg, N. A. Fl. xxii. pt. 2, (1905); Rosendahl in Engler, Bot. Jahrb. xxxvii. 

 Beibl. 83 (1905). 



4 Michx. Fl. i. 270 (1803). 



