Mr. Gardner and Mr. Nevin on Vegetable Physiology. 553 



Mr. Bowman read a paper from Mr. Gardner, * On the internal 

 structure of the wood of Palms.' The attention of Mr. Gardner, who 

 is residing in Brazil, was directed to this subject by the remarks made 

 by Professor Lindley, in his 'Introduction to Botany.' In order to 

 test the truth of the theory of Mohl, he made several experiments on 

 the palms in his district. He made a vertical section of a palm, four 

 inches in circumference, and, by doing this, he could trace very plain- 

 ly woody fibres proceeding from the base of the leaves to the centre 

 of the stem, at an angle of 18 degrees j they then turned downwards 

 and outwards to within a few lines of the external cortical part of the 

 stem, running parallel with its axis. The distance between these two 

 points was about two feet and a half. The fibres were traced quite 

 distinctly up into the centre of the leaf. In answer to the questions 

 proposed by Lindley in his work, the author stated : — 1. That the 

 wood of palms was always hard and compact outside, gradually get- 

 ting softer towards the centre, the fibres of the upper leaves not de- 

 scending to so great a depth as the lower. 2. The wood is much hard- 

 er at the bottom than any other part of the stem, the inhabitants of 

 tropical climates using only this part for economical purposes. 



Professor Lindley observed, that this paper confirmed the views of 

 the structure both of endogens and exogens, which had been increa- 

 singly embraced by botanists. In the first place, the views of Mohl 

 on the structure of endogens were confirmed. There was, however, 

 a slight difference between Mr. Gardner and Professor Mohl ; the 

 latter having stated that the woody fibres of endogens terminated in 

 their cortical integument, whilst the former had traced them only 

 within a Yew lines of this point. In the next place, the paper confirm- 

 ed the theory of the formation of wood from the emanation of fibres 

 from the leaves. Whatever might be the difference between the ar- 

 rangement of the fibres of exogens and endogens, there could be no 

 doubt that their origin was the same. Mr. Gardner had referred, in 

 his paper, to the glandular disks on the woody fibre that were, at one 

 time, thought to characterize the order Coniferae. He would, how- 

 ever, draw the attention of the section to a fact that had lately been 

 discovered, and not hitherto published, that these glandular disks ex- 

 isted on all the woody fibres of plants that yielded resinous matter. 

 Brown first discovered them in the wood of Tasmania {Winter acece), 

 and Griffiths had since demonstrated them in Spherostema (Schizan~ 

 drece). 



Mr. Nevin detailed some experiments on vegetable physiology. 

 The experiments were performed on elms forty years of age, in Fe- 

 bruary, 1836. 



1 . The stem of the tree was denuded, in a circle, of its cortical in- 

 tegument alone, leaving the alburnum beneath uninjured. On the 

 May following the denuded part was filled upbythe exudation of bark 

 and wood from the upper surface of the wound, and the tree had not 

 suffered in growth. 



2. The bark and cambium were removed in the same manner. In 

 August 1837 this tree sickened, and there was no formation of wood 

 or bark in the wounded part. Two developments however, took place 



Third Series. Vol. 1 1 . No. 70. Dec. 1837. * B 



