378 MR. F. N. WILLIAMS: REVISION 
a. genuina, Rohrb. 
Caules et folia nune pubescentes nunc glabrescentes. Folia 
linearia vel lineari-lanceolata, plus minus acuminata, longitudine 
et latitudine ita variantia, ut bis notis lusus vix distingui possint, 
10-35 mm. lg., 2-8 mm. lt. Petala calyce breviora vel eum 
squantia, interdum nulla. 
Lusus 1:—Caules levissime puberuli vel interdum glabres- 
centes, Folia glabra punctulata, forma valde variantia. 
Lusus 2:—Caules levissime puberuli; folia nune pilis brevis- 
simis adspersa nune punctulata glabrescentia. 
Lusus 3 :— Caulis et folia plus minus dense hirsuta. 
P. diffusa, Rohrb. 
Caules humifusi, valde diffusi, longe repentes, interdum 
adscendentes, glabrescentes vel pilis paucis adspersi. Folia 
parva, lineari-spathulata acuminata vel obtusa, pilis paucis ad- 
spersa vel punctulata, valde approximata, 5-8 mm. lg., 1-2 mm. 
lt., læte viridia. Petala calyce paullum breviora. 
A species of very wide distribution in the New World. In 
the United States it extends from N. Carolina to Florida and 
westward to New Mexico. In Central America it is recorded in 
Costa Rica, and is common throughout Mexico from the province 
of Sonora in the north to the peninsula of Yucatan in the south. 
In the West Indies Bancroft and Wilson collected specimens m 
Jamaica, and Mr. Moseley brought specimens from Bermuda in 
the ‘Challenger’ Expedition. The species under one of js 
many forms is found in all the countries of S. America, excepting 
that there are no records for Guiana and Paraguay. Very few 
species of Arenaria extend south of the tropics. Besides 
A. lanuginosa they include only A. fetragyna, near Concepcion 
of Chile, 
and on the summit of Pico de Pilque in the Andes 
A. palustris in Chile and Argentina, and A. serpens Vat 
cola in the Chilean Andes. There are some very iter b 
(somewhat damaged) specimens in Herb. Kew. brought / 
Charles Darwin from Santa Cruz in Patagonia in the COUP ; 
his voyage in H.M.S. ‘ Beagle’ (1832-36). These historical e 
mens not only mark the south limit of the species, but, mor 
important still, the limits of the southern range of the gr 
which is thus fixed at 50°S. At first I thought they might at 
specimens of A. palustris, which is found in North Patagona he 
Lake Nahuelhuapi on the Argentine side of the Andes; m she 
flowers are clearly axillary and not closer together towarc* als 
top of the stem as in the former species, and further the sep 
. andi- 
esting 
