THE PRESENT FLORA OF WEST HAM WASTES. 179
Leontodon autumnalis L. Autumnal Hawksbit. A. A few
plants. F.
Taraxacum vulgare Lam. Dandelion. B. A few plants. F.
Lactuca sativa L. Garden Lettuce. B. A dozen plants or
more, attaining four feet in height ; an escape from cultivation.
This is extremely variable both in the bristly or smooth character
of the leaves, and in the colour, shape and roughness of the
achenes. As those who grow lettuces know, Winter Lettuces,
whether with the "Cos" or "Cabbage" type of leaf, have
brown achenes, rough at the apex : while Summer Lettuces, also
with either type of leaf, have more slender pale grey achenes,
nearly smooth at the apex. It has been suggested that L. sativa
is the cultivated form of L. serriola L (syn. L. Scariola L.) the wild
prickly lettuce, and in Bentham and Hooker's British Flora it is
inferred that L. sativa, L. serriola and L. virosa may be varieties
of a single species. Lettuce has been cultivated in Europe
from remote antiquity.
Sonchus asper Hill. Rough Sowthistle. A, B. Abundant.
F.
5. oleraceus L. Common Sowthistle. A, B. Abundant. F.
Tragopogon pratensis L. Goat's-beard. B. A single plant.
F.
Symphytum officinale L. Comfrey. A, B. A few plants
forming winter rosettes.
Calystegia sepium Brown. Large Bindweed. A, B. Not
unfrequent.
Convolvulus arvensis L. Corn Bindweed. A, B. Frequent.
Solanum Dulcamara L. Bitter-sweet. A. Frequent.
S. nigrum L. Black Nightshade. A, B. A few plants.
S. lycopersicum L. Tomato. A, B. A few plants, garden
escapes of this Tropical American plant.
Lycopus europaeus L. Gipsywort. A, B. Growing between
bricks in the walls, and along the streams, in some cases attaining
four feet in height. The upper leaves of this plant are coarsely
toothed, and the lower ones are often pinnatifid; the leaves of
the winter-buds, which are usually more or less buried in water
or mud, are stiffly pectinate with broad midribs, while the leaves
of the creeping stems are thick, strapshaped and entire. I learn
from my friend Dr. Agnes Arber that pectinate leaves are some-
times formed on plants growing on dry ground. Submerged