Some Observations on the Tuber of Phylloglossum. 
BY 
T. G. B. OSBORN. 
With Plate XXVIII and forty-three Figures in the Text. 
W HEN, towards the end of the growing season 1917- the opportunity 
offered to study Phylloglossum Drummondii in the field near Adelaide, 
it was felt that some observations of interest might be made upon the 
ecology of the plant, with special reference to the behaviour of the tuber as 
an organ of perennation. The scope of the inquiry was unexpectedly 
extended by the discovery that accidentally damaged or detached leaves 
might themselves form new tubers as they lay upon the soil near naturally 
growing plants. A series of observations was therefore made during the 
growing season (May to October) 1918, the results of which are also given 
here. Without wishing at this stage to reopen a discussion as to the 
morphology of Phylloglossum Drummondii , it is felt that the facts now 
presented throw some light on the nature of the tuber that is of importance 
in considering its morphology. 
Field Observations on Phylloglossum. 
The external morphology of Phylloglossum has been so many times 
described that a further account might be deemed superfluous. In the 
present paper, the tuber, formed the previous season, from which arise the 
stem, leaves, roots, and strobilus (should one be produced), and which is 
consequently in process of exhaustion, is termed the ; current tuber \ 1 
The term ‘ old tuber , is restricted to those of previous years, which 
may be found in the soil beside growing plants . 2 These may throw a light 
upon the past history of the plant near which they are found. 
On the Depth of Tuber Formation — Descriptive. 
On examining any large number of plants of Phylloglossum collected 
towards the end of their growing season, the two tubers are usually observed 
side by side at about the same depth below the ground-level. Unlike the 
1 Wernham, H. F. (1910) : Ann. Bot., xxiv, p. 335 . 
2 Thomas, A. P. W. (1902): Proc. Roy. Soc., London, lxix, p. 288 . 
[Annals of Botany, Vol. XXXIII. No. CXXXII. October, 1919.] 
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