183 



St. Hilaire (Morphol. Veg. 142. 1840) and Duchartre (Elem. 

 Bot. 308. 1867) regarded the leaf as a pitchered petiole with a 

 lid which represents the true leaf. Baillon (Compt. Rend. 71 : 

 639. 1870) compared it to a peltate Nelumbian leaf and inter- 

 preted the lower part as the petiole, the pitcher with its wing as 

 corresponding to a ridge on the outer base of peltate leaves of 

 certain Nymphaeaceae, while the lid represents a terminal lobe. 

 Asa Gray described the pitcher as a phyllodium, the terminal lid 

 as the blade of the leaf. Macfarlane (Ann. Bot. 3 : 264. 1889) 

 describes it as the hollowed-out upper part of the midrib " in 

 front of which two elongated green leaflets have fused, producing 

 a prominent wing, a dorsal continuation of the pitchered midrib 

 in flattened form which gives off on either side two leaflets, the 

 whole constituting the lid." He bases this theory largely upon 

 the arrangement of the vascular bundles, which are in two parallel 

 rows with their xylem portions facing each other. Goebel 

 (/. c. 1 : yS. 1 891) criticizes this view, saying that the primor- 

 dium of the leaf resembles that of bud-scales with no differentia- 

 tion into petiole and blade. He regards the lid and pitcher 

 both as parts of the structure termed lamina in the ordi- 

 nary type of leaf. Bower (Ann. Bot. 4: 167. 1889) has 

 reviewed the theories of Macfarlane and Goebel and concluded 

 that " the leaf of Sarracenia is a simple phyllopodium, consisting 

 of (i) a basal sheathing portion, (2) a middle portion which 

 may be hollowed by involution of the upper surface, and bear 

 upon its upper surface a phyllodineous flap, and (3) the lid which 

 is the simple, flattened termination of the leaf." 



The leaves of seedlings, with the exception of the cotyledons, 

 develop as pitchers in all the species that have been examined, 

 Shreve (Bot. Gaz. 42: 118. 1906) describes the development 

 of seedling leaves of S. purpurea as follows : " The first epicoty- 

 ledonary leaf arises opposite the interval between the cotyledons. 

 It is finger-shaped with a somewhat broadened base. On 

 reaching a length about twice its diameter there begins a rapid 

 lateral outgrowth of the tissue of an 0-shaped area on the side of 

 the leaf rudiment which faces the growing point, giving rise to a 

 pit which is destined to become the cavity of the pitchered leaf. 



