328 PROCEEDINGS OF THE AMERICAN ACADEMY. 



discovered. It is evidently related to S. regia, Sims, and »S. laciniata, 

 Cav., but differs from the former very much in the form of its leaves, 

 from the latter in its entire petals, and from both in the entire absence 

 of glandular pubescence. From S. Virginica, L., it differs in petals, 

 pubescence, and texture of the leaves. 



Silexe laciniata, Cav. Prof. W. R. Dudley calls my attention 

 to the fact that the seeds in this species and its broad-leaved variety 

 (S. Greggii) are not infrequently vesicularly crested, as in the Califor- 

 nian S. Parishh, Wats. 



Arenaria Grcenlandica, Spreng. This attractive species, pos- 

 sessing a wide and interesting north and south distribution, seems 

 worthy of special study. The typical form, with subglobose obtusely 

 pointed capsules and with stems few and decumbent from a spreading 

 rosette of somewhat fleshy leaves, occurs chiefly in Greenland and 

 Labrador. The common form of the mountains of Maine, New Hamp- 

 shire, and Eastern New York becomes rather densely matted, and has 

 many erect stems with very numerous erect less fleshy leaves about 

 the base. Its capsules are ovoid to oblong and more or less acutely 

 pointed. Although in temperate latitudes usually confined to rocky 

 soil of the mountains or higher hills, this species descends nearly or 

 quite to the seashore i» Maine, at Bath and at Mt. Desert. It 

 has also been found at Middletown, Conn. When growing at these 

 lower altitudes, the plant is scarcely at all matted and the segregated 

 few-stemmed individuals have simple or at least less fibrous roots and 

 fewer thicker leaves than in the mountain form, with which however 

 they are connected by frequent intergradations. In these forms also 

 the capsule is ovoid or oblong rather than globose. Until recently the 

 Shawangunk Mountains of New York have passed as the southern limit 

 of this species, but there can be no doubt (see Mem. Torr. Club, iii. 

 14) that many of the specimens from the higher Mountains of North 

 Carolina, hitherto referred to A. glabra, Michx., are practically identical 

 with the plant of the White Mountains, notwithstanding the fact that the 

 flowers average smaller. The question whether it is best to retain these 

 forms of temperate regions in the same species with those of Greenland 

 and Labrador presents much difficulty. The differences in habit, size 

 of the flowers, and notching of the petals are often striking. Unfortu- 

 nately, however, no one of these characters holds satisfactorily in a 

 large series of specimens, and it appears that the change from the few- 

 stemmed decumbent plant with a basal rosette of leaves and single 

 simple root to the matted plant with fibrous roots and many stems, erect 

 by mutual crowding, is a difference which may well be due exclusively 



