314 HETBROMORPHY. 
In a variety of Codieum variegatum a similar forma- 
tion may be seen to a minor extent. Hven the common 
Scolopendrium vulgare occasionally produces small 
pitchers of this character, as in the varieties named 
perafero-cornutwm, Moore, and peraferum, Woll.’ 
In carnations leaves may sometimes be seen from 
both surfaces, from which project long, sharp-pointed 
tubular spurs at irregular intervals. A very singular 
illustration of this is figured by Trattinick,’ in which 
the leaves, epicalyx, sepals, and petals, were all provided 
with tubular spurs. 
In Cephalotus follicularis rudimentary or imperfect 
pitchers may be frequently met with, im which the stalk 
of the leaf is tubular and bears at its extremity a very 
small rudimentary leaf-blade. It is not in all cases easy 
to trace the origin and true nature of the ascidium, as 
the venation is sometimes obscure. If there be a single 
well-marked midrib the probability is that the case is 
one of cohesion of the margins of the leaf; but if the 
veins are all of about equal size, and radiate from a 
common stalk, the pouch-like formation is probably 
due to dilatation and hollowing of the petiole. Again, 
when the result of a union of the margins of the 
leaf, the pitcher is generally less regular than when 
formed from the hollowed end of a leaf-stalk. Further 
information is especially needed as to the mode of 
development and formation of these tubular organs, so 
as to ascertain clearly when they are the result of a 
true cupping process, and when of cohesion of the 
margins of one or more leaves. (See Cohesion, p. 31. 
For “bibliographical references consult also A. Braun, 
‘Flora v. Bot. Zeit.,’ 1835, t. xvii, p. 41, Aristolochia.) 
Tubular formations in the flower—A similar formation of 
tubes happens in some double flowers; for instance, 
it is not infrequent in double flowers of Primula 
sinensis, in which tubular petal-like structures are 
' Moore, ‘ Nature Printed Ferns,’ 8vo edition, vol. ii, p. 154, et p. 173. 
> «Flora (B. Z.),’ 1821, vol. iv, p. 717, ¢. tab. 
