[ 1803 ]
THLASPI hirtum.
Hairy Mithridate Mustard,
/ S .
TETRADYNAMIA Siliculosa.
Gen. Char. Pouch notched, inversely heart-shaped,
with several seeds: valves boat-like, their keels
forming the border: partition contrary to the
valves.
Spec. Char. Pouch elliptic-oblong, often hairy, bordered
at the upper part. Stem-leaves arrow-shaped, Jioary,
Style elongated.
Syn. Thlaspi hirtum: Linn. Sp. PI. 901. Sm. Ft.
Brit. 684.
T . vaccariee incano folio perenne. Rail Syn. SO5,
ed. 2. 175.
C o n FIDING in the accuracy of Ray, I Could not but admit
this plant into the Flora Britannica, though Hudson’s T, hirtum
was proved, by an authentic specimen, to be only camr
pestre with hairy fruit. In 1800 Mr. J. Mackay sent me the
true plant from Perthshire, found by Mr. Miller; and the
following year I received a variety with smooth fruit, gathered
in Perthshire and Angusshire by Mr. G. Donn. At length
fresh wild specimens, but with smooth fruit likewise, discovered
by the Rev. G. R. Leathes at Brows ton, Suffolk, have
been sent Mr. Sowerby.'
This species differs from T. campestre, t. 1385, in having
a perennial woody root, more oblong and less tumid pouches,
whose sides are often very hairy, and when destitute of hairs
are but obscurely dotted, never so scaly as in that species.
The petals also are much larger, and more conspicuous. But
for a new and decisive mark I am obliged to Mr. Leathes, who
justly observes that the elongated style, projecting far beyond
the lobes of the pouch, will always distinguish this plant from
the campestre, whose short style is just equal tp those lobes.
Being perennial, the hirtum flowers in June, a month
6 weeks before the other.