1924] Mackenzie,—Double-headed Generic Names 229 
*Solidago nemoralis Ait. Hillsides, south end. 
*Solidago rugosa Mill var.? Hillsides, east end. 
Solidago sempervirens L. Common on beaches; also Gull Island. 
*Sonchus arvensis L. Hill west of hospital. 
*Sonchus asper (L.) Hill. Near wharf. 
*Sonchus oleraceus L. Near beaches. 
Taraxacum officinale Weber [T. Dens-Leonis Desf.]. Not common. 
Xanthium sp. Typha Pond. 
A complete set of exsiccatae of marine algae and land plants (except 
fungi) has been deposited in the herbarium of the Marine Biological 
Laboratory, and duplicates at the herbarium of the University of 
Pennsylvania and at the Gray Herbarium of Harvard University. 
EXPLANATION OF PLATES 146 AND 147. 
The five views reproduced on plates 146 and 147 correspond to photo- 
graphs numbered 1, 2, 4, 11 and 12, respectively, in a series of fifteen views 
taken for the purpose of record and to be preserved at the Marine Biological 
Laboratory at Woods Hole. The points from which these views were taken 
are indicated on the map. 
PLATE 146. Upper view: Looking up the Neck, showing strand (phot. no. 
1). Middle view: Same, looking over tidal flat toward hospital (phot. no. 2). 
Lower view: Typha Pond, looking southwest toward outbuildings in hospital 
grounds (phot. no. 4). 
PLATE 147. Upper view: Looking southeast across area denuded by nest- 
ing terns (phot. no. 11). Lower view: Dry Pond, looking north (from phot. no. 
12). 
DOUBLE-HEADED GENERIC NAMES. 
KENNETH K. MACKENZIE. 
HiLv's British Herbal published in 1756 is a most excellent piece 
of work. The various genera and species are fully described, and all 
of the genera are carefully and well illustrated. Unfortunately 
Hill, in company with some other writers of his time, had ideas of his 
own about generic names. Most of the genera recognized by him 
were given by him under generic names consisting of but one word, 
and, of course, as to these there is no trouble. But in addition to 
such generic names he had some fifty-one other genera, to which he 
gave generic names consisting of two separate words. He never used 
a hyphen connecting the two words so used by him in order to form 
