IRbobora 



JOURNAL OF 



THE NEW ENGLAND BOTANICAL CLUB 



Vol. 8. October, 1906. No. 94 



ACROCHAETIUM AND CHAXTRANSIA IX NORTH 

 AMERICA. 



F. S. COLUNS. 



Dr. E. Bornet has recently published a short but important paper^ 

 which will do much to bring order in a group where confusion has long 

 reigned. Twenty-six species are accepted by him in the two genera, 

 and are grouped according to their characters; they are all based on 

 specimens in the Thuret herbarium, and full descriptions are given 

 of only two species; some of the others have brief notes, but the rest 

 have names alone, or names with references to numbers in exsiccatae. 

 The paper is thus of value chiefly in connection with a large herbarium, 

 well supplied with authentic and classical material. While retaining 

 the older names, the species are grouped largely according to char- 

 acters that had little weight with or were quite disregarded by the 

 authors of the species, so that original references, or the collected 

 descriptions in the Sylloge Alganyn of De Toni, are of little use in criti- 

 cal cases. In the following pages an attempt is made to arrange the 

 North American marine species according to the principles of Bornet's 

 paper, and to give descriptions of all, which should enable the student 

 to determine them from the living plant. Only 12 species have yet 

 been recorded in this region. North America including the West India 

 Islands; and this should be borne in mind in using the key; for 

 instance, Acrochaeiium Dictyotae is the only name given in the key for 

 an asexual plant, with descending endophytic branches, but no trace 

 of the original spore; four other species of this character are known 



1 Deux Chantransia corynibifera Thuret. Acrochaeiium et Chantransia; par M. E. 

 Bornet, Bull. Soc. Bot. de France, Vol. LI, p. XIV. 



