228 



a segregate and that it includes, as it does, all the Florida material 

 heretofore referred to Pteris longifolia are not mentioned at all. 



This omission of the synonym is rather typical of much of 

 Dr. Small's work. It would often be more intelligible nomen- 

 clatorially if unfamiliar segregates were better correlated with past 

 usage and some reason given for shifts of name. One would like 

 to know, for instance, why the name Pycnodoria is applied to the 

 traditional Pteris and Pteris to Pteridium; but no hint of a reason 

 is given.* The Illustrated Flora, a nomenclatorial pioneer in its 

 field, printed a rather full synonymy and became thereby convinc- 

 ing where it was right and detectably wrong where it erred. In the 

 absence of any adequate explanation, one must either accept the 

 author's conclusions unquestioningly — ^and no true scientist 

 desires that — or do over again much work which he has already 

 done. 



One feature which can go far to make or mar a manual is found 

 in its keys. In this book they are, for the most part, adequate, 

 but betray occasional weaknesses. Take the key to the orders 

 on p. 2, for instance. Anyone unfamiliar with the plants would 

 have his troubles in referring the average specimen to its proper 

 order by such characters as these: "Vernation straight or in- 

 clined: prothallium subterranean, yellowish," and "Vernation 

 circinate: prothallium terrestrial or epiphytic, green." They 

 are, to be sure, the outstanding technical characters of the Ophio- 

 glossales and Filicales respectively; but a key is a practical 

 device and is not required to furnish general definitions of the 

 groups to which it leads. As it happens, the sole representative 

 of the Ophioglossales among the species concerned is also the 

 only dimorphic fern which has simple fertile segments and retic- 

 ulate-veined sterile ones. Mention of this fact would have made 

 the key readily workable. Again, on p. 4, "sporangia sessile 

 on a filiform receptacle" and "sporangia borne on normal or 

 modified leaf-blades" make no true contrast. The sporangia 

 are also on leaf-blades in the first case. The principal headings 



* The same is true of Dr. Britton's Flora of Bermuda, where this use of the two 

 names appears, so far as I have observed, for the first time. 



