31-i HETEROMOEPHY. 



In a variety of Codiceum variegatum a similar forma- 

 tion may bo seen to a minor extent. Even the common 

 Scolopendrium vulgare occasionally produces small 

 pitchers of this character, as in the varieties named 

 perafero-cornutum, Moore, and ijeraferum^ 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, in 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. xviii, 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 

 sinensiSf in which tubular petal-like structures are 



' Mooro, ' Nature Printed Ferns,' 8vo edition, vol. ii, p. 154, et p. 173. 

 - ' Flora (B. Z.),' 1821, vol. iv, p. 717, c. tab. 



