through Self-adaptation to a Moist or Aquatic Habit. 733 
Professor Vines adds: ‘ Some few Dicotyledons have closed bundles, 
i. e. without cambium in the stem, e. g. Adoxa, Ranunculus Ficaria , Nym- 
phaeaceae, Myriophyllum , Utricularia, &c.’ Such, of course, agree with all 
Monocotyledons. 
With regard to the similar and the usual condition of monocotyledonous 
stem-bundles, MM. G. Bonnier and Leclerc du Sablon observe: ‘ Chaque 
faisceau est entoure d’une gaine continue de fibres a parois epaissies et 
lignifiees qui ont la meme origine que le parenchyme qui les entoure. . . . Les 
faisceaux offrent une disposition analogue dans certaines Dicotyledones, telles 
que les Ranoncules, Thalictrum , beaucoup d’autres plantes de la famille 
des Ranonculacees et quelques autres encore.’ 1 
Podophyllum peltatum has been described by Mr. Holm, 2 who notes the 
following facts. The petioles of the cotyledons are united into a long tube. 
Such is characteristic of many geophilous plants with a moist soil, as species 
of Anemone and other genera of Ranunculaceae. The vascular system of 
the stem recalls that of a Monocotyledon. The radical leaves are net- 
veined, but their petioles are expanded at the base into a sheath, from which 
many traces enter the subterranean stem. 3 This gives rise to the dispersed 
strands in the stem. The traces in the erect stem have lost their cambium 
and are ‘ closed ’ like those of a Monocotyledon. Cambium, however, is 
found in the bundles of the rhizome; these are arranged in a single circle, 
but without interfascular cambium. 
This species of Podophyllum grows in swampy woods in the Southern 
States of North America. It has a (5-leaved perianth. 
The origin of the coherent petioles may perhaps be traced to the 
ring found on the axis, whence the cotyledons arise, the two crescents of 
which cohere by their edges. This crescent or ring, as stated, is seen in 
Nymphaeaceae. 
Though the rhizome of Nymphaea first suggested the similarity to the 
scattered bundles of Monocotyledons, it is by no means confined to sub¬ 
merged rhizomes. Mr. Worsdell, for example, figures the flowering stems 
of Anemone rivularis, Caltha palustris, Podophyllum peltatum, and Hydrastis 
canadensisP To these petioles may be added those of Thalictrum flavum 
and Rheum. 
As the ‘ closed ’ bundles of Monocotyledons and of certain Dicotyle- 
1 Coursde Botanique, pp. 182-4 & > Figs* 258, 259 (Monocotyledons), Fig. 260 (b) Thalictrum. 
A slight discrepancy seems to be noticeable between Vines’s and Bonnier’s descriptions in the 
words I have italicized in the account of the latter botanist; for while Vines regards the bundle 
sheath as due to the endoderm , which it certainly is in many cases, Bonnier attributes it to the 
medulla or ground tissue of the root. I would venture to suggest that both cases may occur in 
different plants. 
2 Bot. Gaz., xxvii, 1899, P* 4 r 9- 
3 See my paper, On the Origin of the Sheathing Petiole, p. 499. 
4 A Study of the Vascular System in certain Orders of Ranales. Ann. of Bot., xxii, PI. 
32, 33- 
3 c 
