9 [ 1957 j
L A C T U C A virosa.
Strong-scented Lettuce.
SYNGENESIA Pohjgamia-aequalis.
Gen. Char. Rece.pt. naked. Cal. imbricated, cy*
lindrical, with a membranous margin. Down sim-
pie, on a foot-stalk.
Spec. Char. Leaves horizontal, finely toothed C*their
keel prickly.
Svn. Lactuca virosa. Linn. Sp. PI. 1119. Sm. Ft.
Brit. 819. Buds. 337. With. 677. Hull. 175.
Relh. 305. Siblh. 237» Lightf. 429. Woodv.
Suppl. t. 250.
L. sylvestris major, odore opii. Rail Syn. 161 ; and
L. sylvestris folio non laciniato. ib. 162.
T h IS, the largest of our wild lettuces, grows on open sunny
chalky banks and old flint walls, and sometimes on dry gravelly
banks. Our specimens were collected near Mackerell’s
tower, Norwich, and at Battersea. It is biennial, and flowers
from the end of July to the middle of September.
The whole plant abounds with a white milky juice, smelling
like opium and possessing the same narcotic qualities. It
issues suddenly in large drops from the calyx and more tender
leaves on the slightest touch. The stem is erect, wand-like,
round, sparingly leafy, prickly, brown or reddish, panicled at
the summit. Leaves smoothish, rather glaucous, finely and
sharply toothed ; the radical ones numerous,- obovate, undivided
; the rest smaller, clasping the stem, tnore or less
waved or sinuated. Main rib in all beset with straight parallel
prickles. Floral leaves heart-shaped, pointed. Flowers small,
palish yellow; their stalks bearing many small bracteas.
Calyx smooth. Seeds furrowed. Down rough.
Petiver’s figures induce us, with Dr. Stokes, to refer both
the above plants of Ray to this species, though the latter of
the two is mentioned in the Synopsis as if it belonged to L.
Scariola, t. 268. 8