234 PHILOSOPHICAL NOTES OX 



Fig. 88 is part of an apricot leaf. It shows one of the glands 

 reverted to leaflet; and Fig. 89 shows both glands reverted to 

 leaflets. In the two latter cases there were other glands on the 

 petiole. This feature varies much in the different cultivated 

 varieties. In some kinds of cherry the petiole glands are entirely 

 suppressed ; those of Fig. 85 are taken from a variety which had 

 them large and prominent on the petiole. Sometimes they were 

 opposite eacli other, and sometimes at different levels, as shown in 

 this figiu'e.* 



[NTow the two anther cells of the reverted stamens (^, /?, and d) 

 in Fif. 83 appear just to correspond to the glands on the petiole 

 of the cherrv leaf, and are very probably homologous with them. 



An ovule, though potentially a complex body, is initially only 

 a simple cell, like a tooth-gland. The tooth-gland is only an 

 arrested ovule, and the petiole gland only an amalgamation of 

 arrested ovules. Potentially, then, these petiole glands may be 

 either pollen sacs, or nests of ovules. Whether they develop into 

 this or that would depend on the course that circumstances give 

 them. The reverted stamens, although antheroid in structure, 

 occupv the position of amalgamated glands on the margins of 

 leaves and there would appear no good reason to consider these 

 two bodies as other than the same thing. In case of the total 

 suppression of one petiole gland, we would have the reverted 

 stamen (d), Fig. 83. This would not improbably correspond to 

 the one-celled anther of mallow and Grlobe amaranth. 



Teeth- o-lands are to be found on most leaf -like appendages in 

 their youno- state, stipules, leaves and leaflets, bud-scales, and also 

 as terminations of hairs in the so-called glandular hairs. 



Where stipules turn into glands, as in Impatiens (Fig. 43, 

 G. Henslow's " Floral Structures "), their morphology may be 

 similar to that of petiole glands, viz., a fusion of the teeth -glands, 

 with suppression of the stipule-blade. 



The stamens of Polygahi vulgaris, shown in Fig. 90, are 

 probably a fusion of the filaments ; but their anthers being one- 

 celled, they illustrate what I mean by the glands on the tips of 

 leaf-teeth, corresponding to ovules or pollen sacs. Now stamens 

 are sometimes seen to revert to carpels, with ovules on their 



* In the Garden of 26th April 1879, W. W. speculates on the function 

 of these petiole glands, but docs not alhule to their vwrphology. 



