448 Miscellaneous. 



On the Development of the Leaves of the Sarraceniae. 

 By M. H. Baillon. 



The exceptionally formed leaves borne by the Sarracenice are well 

 known as regards their external configuration and the long horn- 

 shaped bag which forms their principal part ; the lid, of variable 

 form, which surmounts, and even the sort of projecting ridge which 

 extends throughout the length of their inner margin, have been 

 well distinguished. But botanists are not agreed as to the interpre- 

 tation of these different regions of the leaf. The most generally 

 accepted opinion upon this point is that put forward by A. Saint- 

 Hilaire and M. Duchartre, amongst others. The former (Morphol. 

 Veget. p. 142) supposes the winged margins of the petiole of Citrus 

 hysirix or of Dioncea approximated and amalgamated, and says that 

 we shall then have the leaf of Sarracenia, formed of an elongated 

 urn (the true petiole) and a lid (the true leaf) ; and the second of 

 these authors likewise says (Elem. de Bot. p. 308) that the ascidium 

 of these plants is generally regarded as formed by the petiole, and 

 their posterior lip or operculum as representing the limb. 



Organogenetic observations alone could show how much of these 

 interpretations was to be admitted. We have therefore studied the 

 development of the leaves in S. pui-purea, which is frequently culti- 

 vated in this country. In their earliest stage these leaves are rejire- 

 sented by small mamilla), the surface of which is at first convex. 

 A little later the base of these organs becomes slightly dilated, and 

 concave within : this is the first rudiment of the sheath, a portion of 

 the leaf which, as we shall see, has nothing to do with the cavity of 

 the pitcher of the Sarnicema. This vaginal portion, which will 

 subsequently acquire a considerable development, behaves here in 

 the same way as in all plants in which it exists, and has no influence 

 upon the composition of the pitcher. The first indication of the 

 latter is a small depression, a sort of pit, at first very slightly marked, 

 which is produced at the top and a little on the inside of the cone 

 which represents the young leaf. This depression is really due only 

 to an inequality of development in the various portions of the apex 

 of the leaf ; and the inequality occurs rather late towards the apex 

 of a leaf of which the petiolar and vaginal portions already exist. 

 In this respect the leaves of the Sarracenke behave nearly like those 

 of the Nymphseaccfe, with which they have so many other analogies. 



At this age the yotmg leaves of the Sarracenice have the same 

 appearance as those of Nepenthes, but for a very different reason, if 

 we admit, with Dr. J, D. Hooker, that the pitchers of the latter are 

 the result of the great development of a gland. Here it is certainly 

 the upper surface of the limb that is at this period reduced to a jwt; 

 and this depression is lined with an epidermis which is the upper 

 epidermis of the leaf, which is developed in proportion as the pit 

 becomes lai'ger, and which subsequently even becomes covered with 

 hairs, the secreting faculty of which has been noticed bj' many ob- 

 servers. The more the pit becomes hollowed out, the more does the 

 limb of the leaf acquire the appearance of certain peltate leaves, 



