4 Rhodora [JANUARY 
species, has the achenes corky and plump, with a groove in the back 
so that the achene appears slightly 2-ridged; its peduncles, stolons, 
and rhachises are usually very pubescent; the young foliage is lustrous 
beneath; and the bractlets of the calyx, though sometimes entire, are 
commonly toothed or lobed. ‘This plant is abundant on gravelly 
shores of the Gulf of St. Lawrence, of the St. John River and its 
tributaries in Maine and New Brunswick, of Lake Champlain, and of 
many rivers and lakes of the interior; and it follows at low levels along 
the mountains from Alaska to New Mexico and southern California. 
It is also occasionally introduced southward on ballast and transported 
gravel. 
The writer has sought in vain for constant characters to separate 
Rydberg's Argentina argentea from his A. Anserina. The key- 
character given by Dr. Rydberg is that the former has the “leaves 
silvery on both sides,” the latter the “leaves green and glabrate above.” 
Careful scrutiny of the diagnoses which describe the characters in one 
plant but fail to bring out their contrasts with parallel characters of the 
other,' shows no difference (except the pubescence) which might not 
1 А, argentea 
“Stolons 1-5 dm. long, white-silky 
with ascending or spreading hairs.” 
"Basal leaves 1-2 dm. long, pinnate, 
with 11-25 larger leaflets and smaller 
ones interposed; rachis with long white, 
at first ascending, soon spreading hairs." 
“ Larger leaflets 1-3 cm. long, obovate, 
rounded at the apex, serrate with 7—20 
ovate or ovate-lanceolate teeth, white-silky 
on both sides or a little greener above, the 
smaller ones less than 1 cm. long and 
few-toothed." 
*'Pedicels 2-7 cm. long, white-silky.”’ 
"Hypanthium and calyx white-silky, 
the former 5-8 mm. wide." 
“Bractlets oblong or elliptic, 4-6 mm. 
Iong, usually entire, about equaling the 
ovate or ovate-lanceolate sepals.” 
“Petals obovate or broadly oval, 6-9 
mm. long." 
“ Achenes 2 mm, long, brown, obliquely 
obovate, corky, with a deep groove,” 
A. Anserina, 
“ Main stem almost none, from a cluster 
of fascicled roots and producing numerous 
runners 3-6 dm. long." 
"Leaves 1-2 dm. long, interruptedly 
pinnate, with 9-31 larger leaflets and 
smaller interposed, in the typical form 
spreading or flat on the ground, slightly 
silky and green above, white-silky and 
tomentose beneath." 
* Larger leaflets 1—4 cm. long, oblong or 
oblanceolate, usually acute, deeply and 
sharply serrate with  linear-lanceolate 
teeth in the European and eastern Ameri- 
can form, more obovate, rounded at the 
apex and with broader ovate or triangular 
teeth in the Rocky Mountain form." 
“Flowers 1-2 cm. in diameter, on pedi- 
cels 3-10 cm, long." 
“Bractlets simple and lanceolate, or 
often broader, ovate-lanceolate, toothed 
or divided, generally a little longer than 
the broadly ovate sepals.” 
"Petals oval, 7-10 mm. long." 
“ Achenes numerous, corky, very thick, 
grooved at the upper end." 
