5 1 6 Osborn . — Some Observations on the Tuber of Phylloglossum. 
Lang, W. H. (1915) : Address to the Botanical Section. Brit. Ass. Report, Manchester, 1915, 
pp. 701-18. 
Osborn, T. G. B. (1918) : On the Habitat and Method of Occurrence in South Australia of Two 
Genera of Lycopods hitherto unrecorded for the State. Trans. Roy. Soc., S. Aus., 
vol. xlii, pp. 1-1 2. 
Robertson, A. (1906) : The Droppers of Tulipa and Erythroniuin . Ann. Bot., vol. xx, 
pp. 429-40. 
Sampson, K. (1916) : The Morphology of Phylloglossum Drummondii , Kunze. Ann. Bot., 
vol. xxx, pp. 314-31. 
(1916) : Note on a Sporeling of Phylloglossum attached to a Prothallus. Ibid., 
pp. 605-7. 
Thomas, A. P. W. (1902) : Preliminary Account of the Prothallium of Phylloglossum. Proc. Roy. 
Soc., London, vol. lxix, pp. 285-91. 
Wernham, H. F. (1910) : The Morphology of Phylloglossum Diummondii. Ann. Bot., vol. xxiv, 
PP- 335-47- 
EXPLANATION OF PLATE XXVIII. 
Illustrating Mr. Osborn’s paper on Some Observations on the Tuber of Phylloglossum. 
All figures x 20. 
c.m. = cell mass ; g.p. = growing-point ; t.s. — tuber stalk ; v.b. = vascular bundle of detached 
leaf ; v.s. = ‘ vascular supply ’ in tuber stalk. 
Photo 1. Transverse section of leaf showing considerable cell mass. A growing-point has 
begun to differentiate. 
Photo 2. Transverse section of leaf showing cell mass. The proliferation of individual epider- 
mal cells is shown on left. Two growing-points are differentiating, and the cell mass between 
them shows a continuous anticlinal wall for several cell rows. Some rhizoids ( r.h .) have developed 
on left side. 
Photo 3. Longitudinal section (somewhat oblique) of leaf found in field (Text-fig. 10), showing 
differentiation of growing-point on cell mass. The greater part of this is of epidermal origin, but 
secondary divisions have occurred in two mesophyll layers. 
Photo 4. Longitudinal section of leaf, showing large cell mass and unusually marked secondary 
development in mesophyll. Note the injured surface of this leaf is oblique. 
Photo 5. Longitudinal section of leaf with small cell mass and stalk of tuber. The essentially 
epidermal origin of the adventitious structure formed in regeneration is seen. 
Photo 6. Transverse section of leaf with irregularly lobed cell mass. The larger lobe has 
formed a growing-point which has invaginated and lies at the base of a short pit, the channel. 
Photo 7. Longitudinal section of leaf and adventitious tuber after three months’ growth. The 
tuber has swollen and the growing-point is situated in a chamber at the upper pole. The tuber as yet 
shows no differentiation, nor is there any ‘ vascular supply ’ in the stalk. 
Photo 8. Transverse section of leaf bearing adventitious tuber, which is nearly fully developed. 
Storage tissue, tuber coat, and growing-point are all visible, and rhizoids are present on the tuber 
and stalk. 
Photo 9. Longitudinal section of leaf and adventitious tuber at about the same stage as that in 
Photo 8. The bend on the tuber stalk is accidental. 
Photo 10. Somewhat tangential section of same leaf as Photo 9, showing ‘tracheides’ of 
‘ vascular supply ’ in the cell mass, and tuber stalk, with expansion at the distal end of the latter. 
The opening of the channel to the exterior ( o.c .) is seen. 
Photo 11. Longitudinal section of adventitious growth from detached leaf (Text-fig. 20) with 
tuber coat, bearing rhizoids, storage tissue, and growing-point. The ‘ leaflet ’ (/.) is seen passing out 
of the plane of the section on left. 
Photo 12. Transverse section of leaf (Text-fig. 25) bearing many cell masses, one of which is 
becoming tuberous {i.b.) directly, without fanning a definite apex. 
