1906] SHREVE—SARRACENIA PURPUREA 121 
the wing is just beginning to appear. Figs. 56-61 represent cross 
sections of the primordium at this age in the places indicated in 
fig. 55.. 
In older leaves, such as are represented in fig. 62, the base of the 
leaf primordium is stoutly crescentic in cross section. Through the 
groove at the inner side of the leaf base the next younger leaf appears 
(jigs. 55 and 62). The groove becomes narrower and more shallow 
as we pass up the leaf and ends just short of the bottom of the cavity 
of the pitcher (fig. 62). Above the end of the groove there is a short 
portion of the young leaf which is circular in cross section, above 
which in turn the narrow flattened outgrowth of the wing has become 
More conspicuous. The wing rudiment ends rather abruptly at a 
point where retardation of growth in diameter indicates the line of 
demarcation between the pitcher and cover. The cavity of the pitcher 
at this stage reaches as far as the upper end of the circular portion 
of the base. 
There have been many suggestions as to the homology of the parts 
of the pitchered leaf of Sarracenia. A view held by many is that 
the pitchered portion of the leaf is derived from the primordium of 
the petiole and the cover from the primordium of the lamina. Gokr- 
BEL (/. c.) points out that since there can be no distinction in the very 
young leaf of primordia of petiole and lamina there can be no line 
drawn as to what portions of the pitchered leaf “represent” these 
Structures. 
The anatomy of the mature leaf was first worked out by VoGL;° 
it has more recently been reviewed by GoEBEL (/. c.), and minor 
contributions have been made by ScHIMPER® (1882) and ZIPPERER 
(/. c.). The first leaf rudiments unfolded in the spring are aborted 
(fg. 62), consisting of the sheathing base surmounted by the minute 
retarded primordium of pitcher and cover. These are usually 
three in number, and may occur in plants which do not bloom, as 
well as in those which do. In the latter case the aborted leaves are 
those just above the one to which-the flower appears to be axillary. 
5 Die Blatter der Sarracenia purpurea. Sitzungsb. Wiener Akad. Wiss. Math.- 
Naturw. 50: 281-301. pls. 2. 1864. 
°Notizen iiber insectfressende Pflanzen. Bot. Zeit. 40:225-234, 241-248. 
Pl. 4 (figs. I~3). 1882. 
