through Self-adaptation to a Moist or Aquatic Habit. 729 
Miss Sargant, in her paper 1 2 3 4 On the Origin of the Seed-leaf in Mono¬ 
cotyledons 7 takes the present prevailing view that this class was not prece¬ 
dent to, but descended from Dicotyledons, and says, with regard to Allium , 
‘the second half of the root-stele might originally have been supplied by the 
trace of a second cotyledon opposite the first.’ 2 She also suggests that the 
two bundles of the cotyledon and hypocotyl of Anemarrhena may be traces 
representing the two distinct cotyledons of some ancestor. If this view is 
justified the 8 cotyledon’ of Anemarrhena , and probably that of all Mono¬ 
cotyledons, must be equivalent to both the seed-leaves of Dicotyledons.’ 3 
Miss Sargant would seem thus to consider that the single 8 cotyledon ’ of 
Monocotyledons results from a fusion of the two, characteristic of Dicotyle¬ 
dons ; but there is some ambiguity in her use of the term ‘ cotyledon 
Thus, in this sentence : ‘ Three bundles from each cotyledon [meaning the 
blade ] enter the petiolar cylinder.’ 4 But elsewhere, speaking of Eranthis 
hiemalis , she says : 4 The partial union of two cotyledons [meaning the 
petioles only ] is undisputed.’ 5 Again, ‘ The two cotyledons of Primitive 
Angiosperms have united to form the single member in Monocotyledons.’ G 
This change in the use of the term is a little confusing. R. Ficaria has been 
thought to indicate a fusion because its single cotyledon has often an 
emarginate blade, supposed to consist of two united ; but it sometimes has 
none, or again two sinus. Miss Sargant adds that each of the two strands 
in the petiolar cylinder of Eranthis gives rise to three just before entering 
the blade. But those of Anemarrhena supply none. This countenances the 
view I have expressed elsewhere, and maintained by certain botanists in 
1875, that the ordinary so-called ‘leaf’ of Monocotyledons with parallel 
venation is really homologous with the petiole only. 7 Others, as Sachs, 
regard the blade as arising directly from the sheath ; but no mention is made 
of the parallel venation, which, to my mind, decides the question. 
I would summarize my position as follows:— 
What is suppressed in the embryo of Monocotyledons consists of— 
1. The blade of the existing so-called single cotyledon, this being 
homologous with the petiole. 
2. Both the blade and th zpetiole of the missing cotyledon. 
What is retained consists of— 
j. The petiole only of the existing cotyledon. 
2. The single bundle of the petiole of the missing cotyledon (if present). 
1 New Phytologist, i, p. 107. 
2 op. cit., p. 109. 
3 op. cit., p. no. 
4 Origin of the Seed-leaf in Monocotyledons. New Phytologist, vol. i, p. in. 
5 op. cit., p. 113. 
6 Reconstruction, &c. Ann. Bot., xxii, p. 183. 
7 M. D. Clos mentions de Candolle and Treviranus, in Des elements morphologiques de la feuille 
chez les Monocotylifs. M^m. de TAcad. des Sci. Toulouse, 1875. 
