CONTRIBUTIONS FROM THE GRAY HERBARIUM OF 
HARVARD UNIVERSITY, NEW SERIES, No. XV. 
By M. L. FERNALD. 
Presented by B. L, Robinson, March 8, 1899. Received March 15, 1899. 
I.— ELEOCHARIS OVATA AND ITS AMERICAN ALLIES. 
In attempting to place satisfactorily a number of strikingly different 
American plants, which, according to the standard works upon that 
group, must all be called Eleocharis ovata, a detailed study of the achenes 
has shown that our present conception of the species — especially in 
America — is remarkably indefinite. The commonest American plant 
passing as Eleocharis ovata is an annual species with many erect or 
ascending comparatively stout culms from 1 to 5 dm. high, capped by 
thick globose-ovoid or ovate-oblong obtuse densely flowered brown heads, 
to13 mm. long. The closely appressed ascending obovate-oblong or 
suborbicular scales are blunt, with scarious margins. The tubercle, 
usually as broad as the cuneate-obovate achene, is depressed, somewhat 
resembling in outline a high-crowned tam-o’-shanter cap; it is generally 
one third as high as the body of the achene. This common American 
plant (Figs. 1 to 7), now accepted as Z. ovata, was described in 1809 by 
Willdenow as Scirpus obtusus, and it was subsequently transferred by 
Schultes to Eleocharis. For three fourths of a century the plant was 
generally treated by Torrey, Gray, and other recognized authorities on 
the group, as a distinct American species. In his monograph of the 
Cyperacee, however, Béckeler reduced’ our common American Eleo- 
charis (Heleocharis) obtusa to the well known E. ovata of central 
Europe. This disposition of the plant was accepted by Mr. C. B. Clarke 
in his study of the European species of Eleocharis,’ and it has been 
adopted by subsequent American students of the group, — Britton, Wat- 
‘on, etc. Habitally the two plants are essentially alike, but a careful 
examination of achenes from an abundance of American and European 
specimens reveals certain differences which appear quite constant. The 
EE DEES 
’ Bickeler, Linnea, (1869-70), XXXVI. 463. 2 Jour. Bot., XXV. 268. 
