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348 WHAT IS THE THAMES-SIDE BRASSICA ?
Apparently, there is the excellent authority of Mr. Syme for the
name which is adopted in the ' piora of Middlesex ;' but Mr. J. T.
Syme's use of the name is quoted from a record in the ' Phytologist
so long back as 1852. I recognize in the present Mr. Boswell-Syme,
of 'English Botany,' third edition, our best living authority for the
nomenclature and description of British plants. And I propose here
to show, in reliance on his own words, that lie could not possibly now
refer the Thames-side plant to Napus, although he may erroneously
have done so in 1853, through not then having become familiar with
it in its early growth,—say, between August and April. In the third
edition of ' English Botany,' in which the descriptions of our Britisii
plants are so ably re-written by its editor, we find an aggregate Bras-
slca folymorplia subdivided into three segregates or subspecies, which
are thus distinguished by their diagnostic characters and places of
growth :—
(1.) Brassica Napus.—Leaves all glaucous and glabrous. Elowers
remaining till the corymb expands into a short raceme.—A weed in
cultivated ground, or more frequently the remains of a field of Rape-
or Cole-seed.
(2.) Brassica campestris.— Leaves all glaucous, the radical ones
hispid, the rest glabrous. Flowers falling off before the corymb
lengthens into a raceme.—A weed in cultivated ground, and by the
banks of rivers and ditches. "Swedish Turnip."
(3.) Brassica Rapa.—Radical leaves green not glaucous, hispid
stem leaves glaucous and glabrous. Elowers falling off before the
corymb lengthens into a raceme.—A straggler in cultivated ground,
usually the remains of a field of Turnips. " The Turnip."
The editor remarks on the difficulty of distinguishing his third sub-
species from the other two, and he states that B. campestris is the
only one which can be considered at all " well established " in this
country. Yet, if the characters assigned to the first subspecies are
correct, it should be easy to show that the Thames-side plant cannot
be Napus, whatever else it may be pronounced. Its radical leaves are
neither glaucous nor glabrous, being dark grass-green and much his-
pid ; and the petals fall early, leaving the elongated raceme formed of
young pods, not of flowers. How thus can it be Napus? Surely
not because it wants all the three distinctive characters attributed to
Napus ! Moreover, it is not simply " a weed in cultivated ground,"
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