( 169 ) 
Mochringia lateriflora (Li.) Fenzl. Dawson (Williams) ; 
Five-finger Rapids (Tarleton). 
Merckia physodes Fisch. Mouth of Klondike (Williams) ; 
above Stewart River (Tarleton). | 
Arenaria laricifolia LL. Dawson (Williams). 
Arenaria trifora(L.)S. Wats. Lebarge Island (Tarleton). 
Arenaria Dawsonensis Britton, sp. nov. 
Glabrous. Stems very slender, several times forked, 1.5~-3 
dm. high. Leaves narrowly linear, smooth, blunt-pointed, 
the lower 1-1.5 cm. long, 0.5-1.3 mm. wide, firm, the lowest 
sometimes with fascicles of smaller ones in their axils, the 
uppermost reduced to bracts ; lower internodes 4-6 cm. long ; 
pedicels filiform, divergent-ascending, straight ; sepals oblong- 
lanceolate, acute, strongly 3-nerved, 4 mm. long, I-I.5 mm. 
wide, the calyx impressed at the base; petals oblong, a little 
shorter than the sepals or equalling them; pod narrowly 
ovoid, membranous, 3-valved, a little longer than the sepals: 
seeds oval-oblong, reddish brown, 0.6—-0.7 mm. long, rough- 
ened with low irregular ridges. 
Dawson, R. S. Williams, July 16, 1899. 
Apparently nearest to A. Michauxii (Fenzl.) Hook., but 
with short petals, merely acute sepals and much longer inter- 
nodes. 
Family RANUNCULACEAE. 
Actaea arguta Nutt. Five-finger Rapids (Tarleton). 
Anemone Richardsont Hook. Near mouth of Bonanza 
(Williams); near Selwyn River (Tarleton). 
Anemone parvifiora Michx. Dawson (Williams); White 
Horse Rapids and Lake Bennett (Tarleton). 
Anemone globosa Nutt. Lake Lebarge and White Horse 
Rapids (Tarleton). 
Pulsatilla hirsutisstma (Pursh) Britton. Near Hootalinqua 
(Williams); Lake Bennett and Lake Lebarge (Tarleton). 
Ranunculus Yukonensis Britton, sp. nov. 
Group of ft. Purshiz. Stems almost filiform, 1 dm. long 
or less, sparingly pubescent toward the end. Leaves slender- 
petioled, 6-14 mm. wide, dissected into linear, entire or 
