In a recent article on the distribution of _Isoetes saccharata_, in the _Botanical Gazette_, the author notes that _I. saccharata_ is found only in Chesapeake Bay, while _I. riparia_, a form that closely resembles it, is found only in Delaware Bay, and that, notwithstanding the small differences between the two, there have been described two intermediate forms, _I. saccharata Palmeri_ and _I. s. reticulata_. From this and other facts, he inclines to the belief that _I. riparia_ is simply an extreme form of _saccharata_. A curious circumstance connected with the species and forms is that specimens collected in a certain locality appeared one season as the type and the next as the variety. This is not the only instance on record of _Isoetes_ species intergrading. Mr. A. A. Eaton has noted that the variety _Californica_ of _I. melanopoda_ intergrades on the one hand with _I. Howelli_ and on the other with the type, while specimens referred to _I. mexicana_ by Underwood have since been identified as _I. Orcuttii_ and _I. melanopoda_. All this seems to indicate that the systematists have not yet got hold of the proper characters upon which to found specific differences, and there is here a chance for a philosophical botanist to distinguish himself. It is not enough that the plants look different; the differences must be specific. All of the forms of _Equisetum arvense_ look different, but they are not species by any means. ⁂ Plans are being made for another meeting of fern students at St. Louis this winter, during the session of the American Association for the Advancement of Science. There is a prospect of some excellent papers to be presented, and a large and enthusiastic meeting is assured. Programs and other information may be obtained of Prof. N. L. T. Nelson, Central High School, St. Louis, Mo., or of the editor of The Fern Bulletin. The editor expects to be at the meeting and hopes to meet there the majority of his readers. BOOK NEWS.