July 19, 1912] 



SCIENCE 



busy with the classification of the species and 

 very little has been done with the genera 

 since the exposition by Bentham and Hooker 

 (Gen. PI. 3'. 1883) and by Hackel (Engl. & 

 Prantl, Pflanzenfam. 2\ 1887). It is true 

 that authors have attempted revisions of gen- 

 era in local floras, recognizing the necessity of 

 rearranging groups to accord with additional 

 facts. But too often such rearrangement has 

 been based solely upon species growing within 

 the region covered by the flora. Nature knows 

 no such limitations. Groups that are perfectly 

 distinct in one area may in another area be 

 connected by transition forms. Mrs. Chase 

 has begun the revision of the genera of the 

 entire family throughout the world. The four 

 papers mentioned deal with the tribe Panicese, 

 which will be completed in one more paper. 

 The genera still to be discussed belong to the 

 subdivision of the tribe in which the spikelets 

 are surrounded by bristles. Under each genus 

 is given a full discussion of the synonymy, a 

 description of the genus as limited by the 

 author, and, in American genera, an excellent 

 text figure of the spikelet drawn from the type 

 species. The author has been consistent in 

 recognizing genera, basing validity upon char- 

 acters of the same kind and degree. Such 

 classification is necessarily the result of her 

 botanical judgment, but this judgment is 

 based upon a careful comparison of characters 

 of the group as represented throughout the 

 world, and unbiased by tradition or authority. 

 Those who have given only superficial atten- 

 tion to grasses, and to whom certain names 

 have become familiar, will " view with alarm " 

 the splitting up of such genera as the heter- 

 ogeneous Panicum. But a close study must 

 convince the most conservative that the great 

 genera Panicum (in the restricted sense) and 

 Paspalum, recognized as distinct since their 

 separation by Linnaeus, are more closely allied 

 than any of the segregates from Panicum 

 recognized by Mrs. Chase, such as Synther- 

 isma (Digitaria). In fact in the excellent 

 synoptical key to genera, appearing in Part 

 IV., Valota (Panicum leucophceum) , Syn- 

 therisma and Leptoloma (Panicum, cognatum) 

 are numbered 3, 4 and 5, while Panicum and 



lum are numbered 16 and 17. The au- 

 thor quite properly revises the nomenclature 

 of the species in each genus in so far as this 

 can be done without a further study of type 

 specimens. Much just criticism has been di- 

 rected against what some have been pleased 

 to call " name-juggling," a sort of pop-gun 

 revision, in which the primary purpose has 

 been to change names or create new combina- 

 tions. The nomenclature of a group of plants 

 should be revised by the person who revises the 

 taxonomy. And nomenclature in its applica- 

 tions should not be considered apart from the 

 study of the plants involved. Mrs. Chase, 

 however, has given the taxonomy careful study 

 and is in position to adjust the nomenclature. 

 It is hoped that the other tribes of grasses may 

 be revised by her in the same manner. 



North American Flora. Poacew : G. V. Nash 



(N. A. Fl. 17: 77-98. 1909). 



In this number only a beginning is made, 

 including a key to the thirteen tribes, and 

 descriptions of the first 18 genera, up to and 

 including Elionurus. The form of treatment 

 is fixed by the general style of the work, for 

 which reason certain criticisms must be shared 

 by the editors. But the style adopted by the 

 editors is the result of definite consideration 

 and any criticism of this must take the form 

 of a protest or regret. Probably the omission 

 that the student will most often regret is the 

 lack of cited specimens. To the student of 

 grasses the mention of a few selected speci- 

 mens might well take the place of the plates 

 listed. It is also to be regretted that room 

 could not be found for critical notes on syn- 

 onymy. It is a good idea to give the type 

 species of each genus, but there will be many 

 cases where selection must be' made and it 

 would be helpful if the reasons for a certain 

 choice were given. In Hemarthria the first 

 of two species was chosen. In Miscanthus the 

 second species is chosen. The reason for re- 

 jecting the first species is a good one, namely, 

 because Andersson, the author of the genus, 

 remarks that the first species, M. capensis, 

 shows a transition to other genera, but it 

 would be more satisfactory to the student if 



