Osborn . — Some Observations on the Tuber of Phy l log loss u m . 5 1 5 
Summary. 
1. Phylloglossum Drummondii occurs in South Australia as a member 
of the geophytic element in the flora of an area subject to prolonged summer 
desiccation. 
2. The examination of a number of living plants has shown that, whilst 
the average depth of the current tuber is about 1 c.m., owing to various 
accidental causes it may range from a surface position to a depth of at 
least 2 cm. 
3. Whatever the depth of the current tuber, the growing plant tends to 
form its new tuber at an average depth of 1 cm. This adjustment is effected 
by variation in length of the tuber stalk. 
4. A new method of vegetative reproduction is described for Phyllo- 
glossum. This consists in regeneration from leaves, injured or detached by 
accidental causes. 
5. In regeneration there is first produced an adventitious cell mass, at 
or near the proximal end of the leaf and arising from the abaxial surface. 
This cell mass is regarded as the protocorm. 
6. From a growing-point differentiated on the cell mass a tuber 
develops which resembles that formed by the normal plant. 
7. Reasons are advanced for regarding the protocorm and tuber as two 
distinct and independent structures. 
8. The results of the investigation emphasize the biological value of 
the tuber, and morphological interpretations, based on anatomical evidence 
only, should be accepted with caution. 
I am greatly indebted to Professor W. H. Lang, F.R.S., for his kindness 
in seeing this paper through the press. 
Botanical Department, 
University of Adelaide. 
Literature cited. 
Bower, F. O. (1885) : On the Development and Morphology of Phylloglossum Drummondii. 
Phil. Trans. Roy. Soc., London, vol. clxxvi, pp. 665-78. 
— (1908) : The Origin of a Land Flora. 
(1914): Address to the Botanical Section. Brit. Ass. Report, Australia, 1914, 
pp. 560-72. 
Goebel, K. (1900) : Organography of Plants. Part I. General Organography. 
(1905): Organography of Plants. Part II. Special Organography. 
Holloway, J. E. (1914) : Preliminary Note on the Protocorm of Lycopodium laterale , R. Br, 
Trans, and Proc. N.Z. Inst., vol. xlvii, pp. 73—5. 
(1915): Studies in the New Zealand Species of Lycopodium. Part I. Ibid., 
vol. xlviii, pp. 253-303. 
. (1916) : Studies in the New Zealand Species ot Lycopodium. Part II. Methods 
of Vegetative Reproduction. Ibid., vol. xlix, pp. 80-93. 
