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DISTRIBUTION OF CARKX AGGREGATA F.\ THE 

 PHILADELPHIA RECIION 



By Bayard Long 



Of new species in Carex, proposed in recent years, few have 

 been more instrumental in clearing up long-standing difificulties 

 in a critical group than Carex a^i^regata Mackenzie, oi the 

 Muhlcnbergianae. 



The describing of new species in groups acknowledged by all 

 students to be difficult does not always meet with general 

 approval, however, especially where certain of the species are 

 rather commonly recognized as not being formed of a thoroughly 

 consistent series. The reason is patent: a group is often made 

 even more confusing and difficult for practical use than before. 

 Certain well-known genera of the Rosaceae (in its more compre- 

 hensive sense), which have figured largely in botanical literature 

 in late years, come to mind. But when a form is as well differ- 

 entiated as Mr. K. K. Mackenzie's C. aggregata we can ha\"e no 

 criticism about "close splitting," but only appreciation of the 

 author's close and careful study and the benefit accruing to the 

 science by this competent understanding and solution of a 

 troublesome problem. 



The mute evidence on the labels of the plant now known as 

 Carex aggregata, from the Philadelphia region alone, is sufficient 

 to show that critical work in segregation has long been needed 

 among the allies of C. Muhlenhergii. There need be selected 

 from the Herbarium of the Philadelphia Botanical Club only 

 three sheets to find that the gamut has been run all the way 

 from Muhlenbergii, sparganoides, and cephaloidea to alopecoidea 

 and conjuncta. This material has passed through the hands of 

 some half-dozen botanists, all men more or less well known to 

 botanical literature, and amply demonstrates, I think, the diffi- 

 culty experienced by the older botanists in naming Carices of 

 this alliance. 



My acquaintance with the plant dates from 1909. June 19, 

 near Fern Rock Station in Philadelphia, I have the distinct 

 recollection of finding on a thicket margin a sedge with rather 



