Potervum. | XXXVI, ROSACEA. 141 
X. POTERIUM. POTERIUM. 
Herbs, with a perennial stock, ascending or erect annual stems, and 
pinnate leaves. Flowers without petals, in dense, globular or ovate 
heads at the ends of long peduncles, as in Sangmsorba, but most fre- 
quently monccious. Calyx in the males 4-lobed, the stamens numerous, 
with long filaments. Calyx in the female tubular, contracted at the 
mouth, with 4 small deciduous teeth. After flowering it becomes quad- 
rangular, closely enclosing 1 or rarely 2 1-seeded carpels. 
A small genus, chiefly south European and western Asiatic, gene- 
rally preferring drier and more rocky situations than the Sangwisorbas. 
1. P. Sanguisorba, Linn. (fig. 327). Salad Burnet.—A glabrous or 
very slightly downy perennial, much like the Sanguisorba but smaller, 
the stem seldom above a foot high. Leaflets small, ovate, deeply 
toothed, often 15 to 19 to each leaf. Heads of flowers smaller and 
more globular than in Sanguzsorba, of a light green colour, very seldom 
acquiring a purplish tinge. Lower flowers all males, with the numerous 
stamens projecting in hanging tufts; upper flowers female, with a long 
style ending in a purple, tufted stigma. Ripe calyx from 1 to 2 lines 
long, more or less distinctly quadrangular, and irregularly wrinkled and 
pitted. 
In dry pastures and clefts of limestone rocks, in central and southern 
Europe, and temperate Russian Asia, extending northwards into southern 
Sweden. In Britain, generally spread over the limestone districts of 
England, but scarce in Scotland and Ireland. The ripe calyx or fruit 
varies in size and in the prominence of the wrinkles, constituting in the 
eyes of southern botanists several distinct species ; one of these, with 
the ripe calyx near 2 lines long, and very distinctly pitted and marked 
with little asperities, is P. muricatum, Spach. 
XI. AGRIMONIA. AGRIMONY. 
Herbs, with a perennial stock, erect stems, pinnate leaves with dis- 
tinct segments or leaflets, and yellow flowers in long, terminal, simple, 
loose spikes. Calyx 5-toothed. Petals 5. Stamens few. Carpels 
usually 2, enclosed within the dry, persistent calyx, which is covered, 
when ripe, with hooked bristles. 
The genus comprises but very few European, north Asiatic, and 
North American species, easily known by their inflorescence and their 
fruit. 
1, A. Eupatoria, Linn. (fig. 328). Agrimony.—Stems 2 or 3 feet 
high, more or less clothed, as well as the leaves, with soft hairs. Lower 
leaves often 6 inches long, with from 5 to 9 distinct, ovate, coarsely 
toothed leaflets, about an inch long, intermixed with a number of much 
smaller ones; the upper leaves gradually smaller, with fewer leaflets. 
Spike long and leafless, but each flower in the axil of a small 3-cleft 
bract, with 2 smaller 3-toothed bracteoles on the very short pedicel. 
Tube of the calyx hairy and erect when in flower, turned downwards 
after flowering, when it becomes thickly covered at the top with hooked, 
green or reddish bristles, forming a small burr. Petals rather small, 
oblong. Stamens short, often not more than 6 or 7, but sometimes 
twice that number. | 
On roadsides, waste places, borders of fields, &c., over nearly the 
