BOTANIC MATERIA MEDICA, 203 
Hedeoma, Ponnyroyal, Hedeoma Pulegio- 
ides.—Natural order Labiate. Said to be a na- 
tive of North America, but found growing in 
Europe. This little plant, with its creeping 
perennial root, sends up a stem very much 
‘branched, which is adorned with leaves ovate-. 
oblong in shape and about half an inch long; 
pubescent, and with rather long petioles of a 
light green color, having upon their surfaces a 
number of spots or pellucid dots; corolla small, 
of a light purple color, having two stamens and 
one pistil; calyx tubular. This common little 
plant is well known to every country boy, and 
contains some /annin, extractive matter and a 
volatile oil, of which we will speak later on. 
Like the rest of the mints, it is carminative, 
stimulant and emmenagogue in its medicinal ef- 
fects, and when found it is usually in one ounce 
compressed packages. It has been given in 
form of an infusion, but the only recognized 
officinal part of the plant is the oil. The name 
is said to be derived from the Greek hedeta- 
tag a pleasant odor, and the Latin pluler, a 
ea, 
Helianthemum, Frostweed or Frostwort, 
Helianthemum Canadense.—Natural order Cis- 
taceze. A low perennial, native of Europe, but 
found growing in many parts of North Amer- 
ica. The leaves are entire, quite small and 
lanceolate in shape, with frosty pubescence; in 
fact, the whole plant presents to the eye a white 
or frosty look. The flower, according to Prof. 
Gray, blooms for a day only; according to some 
the frostweed has two sets of flowers, the first 
solitary and terminal and quite large, the suc- 
