Prof, Buckman on Cnicus tuberosus. 151] 
lost for many years in one locality, and subsequently occur- 
ring in another; and yet, though the collecting botanist may 
perhaps felicitate us upon restoring this to the British flora, I 
have myself great hesitation in receiving it as a true and un- 
doubted species, the grounds for which I would shortly sum up 
as follows:— 
It occurs sparingly at Avebury, surrounded by the true Cnicus 
acaulis and Cnicus acanthoides in great abundance. 
Its most important distinctive character will be found in the 
radical tubers, which, in full-grown examples, are somewhat 
large and fleshy, and unilaterally placed on the rhizome. In 
smaller specimens the roots are long and flexile, but not ex- 
panded into tubers,—which is just the state in which they occur 
in the Cnicus acaulis. 
It is true that it cannot be described as acauline, as the stem 
is more than a foot in height; but this is also often the case with 
the true acaulis, as we have now before us examples of this spe- 
cies several inches high. , 
From these circumstances, in connexion with the rarity of the 
tuberous form in a plant that seeds so abundantly, each head of 
flowers being capable of perfecting as many as 150 seeds,— 
taking also into consideration the well-known sporting propen- 
sity of this genus,—I cannot help thinking this to be a hybrid; 
and from the fact of the abundance of the two forms before indi- 
cated in its immediate vicinity, we may not unreasonably look 
upon them as the origin of our tuberous type. ‘ 
There is perhaps no genus of plants more perplexing to the 
botanist than that of Carduus, which is now made to include 
Cnicus ; hence the variation in the number of species in our 
different floras; and thus Babington heads: his descriptions 
of them with the following significant note— many hybrids 
occur in this genus*;” and my friend Lees has kindly furnished 
me with the following note upon another disputed species, which 
bears directly upon this question :— 
_ “Tn August 1856, I found the Cnicus Forsteri of Smith, in 
a field near Crowle, Worcestershire. In the same marshy field 
was a considerable quantity of Cnicus pratensis and a very nu- 
merous growth of C. palustris. The position of Forster’s Thistle 
was between the C. pratensis and C. palustris, so as to give rise 
to an immediate suspicion of its hybridity ; and, upon examina- 
tion, the characters shown by C. Forstert were exactly interme- 
diate also. The leaves were much like those of C. palustris, 
while the stem and flowers were in small clusters, instead of 
being single as in the latter. Indeed, the result of my examina- 
tion convinced me that C. Forsteri could be only a hybrid; and 
* Manual of British Botany, 3rd edition. 
