Prof. Ch. Morren on the Morphology of the Ascidia. 307 



be represented by the inner surface of the ascidium. Let us 

 attend to this fact because we shall return to it by and by. 



Dr. Lindley, however, with the skill which characterizes all 

 his literary productions, adds, that it would be wrong to sup- 

 pose that all pitchers are by nature petioles ; he even figures 

 Dischidia Rafflesiana, the leaves of which are evidently united 

 at their margins to form the singular hollow organs of this 

 plant. In Marcgravia and Norantea it is no longer the leaves, 

 properly so called, which form the ascidia, but the bracts 

 united likewise by their margins. In this last case it is the 

 blade which constitutes the organ. 



There would then be two systems of ascidia, petiolar, and 

 lamellar or limbar, the latter formed by the cohesion of the 

 margins of the blade, the former by the cohesion of the mar- 

 gins of the wings of a petiole. In none of these cases would 

 it be a petiole hollowed in the interior and rendered fistular, 

 being at the same time open; in like manner as the pedicels and 

 the leaves of the garlics are, remaining closed. M. Alphonse 

 DeCandoUe also thinks that it is the petiole which unites toge- 

 ther the two margins of its wings to form the ascidium in Ne- 

 penthes and in Sarracenia^, This opinion was moreover con- 

 formable to the theory of M. DeCandolle, senior, who also 

 regards the lid as the representative of the blade, and the 

 pitcher as a dilatation of the petiole ; but adds, that in the 

 present state of the science, it will always be difficult to form 

 a decided opinion with respect to this subject f. M. DeCan- 

 dolle, senior, however mentions small cups formed at the ex- 

 pense of the tendrils in Vicia, and others which arose from the 

 expansion of the medial nerve prolonged beyond the blade of 

 the leaf in cabbages. 



That which M. DeCandolle says of the Vicia naturally brings 

 back the question to where it was left by Willdenow J, who con- 

 nects the pitchers to the ochreae oi Polygonece, to the spathes, 

 to the ramenta, and to the stipules on one hand, and on the 

 other hand to the aeriferous vesicles of the Utriculariae, to the 

 ligula, the involucra and other analogous organs. But this 



* Introduction a I'etude de la botanique, suites k BufFon, t. i. p. 88. 



t Organographie, vol. i. p. 320. 



I Grundriss der Krauterkunde, § 52. p. 94. (ed. 1802). 



z 2 



