486 Osborn. — Some Observations on the Tuber of Phylloglossum. 
perennating organs of many geophytes, these two structures, products of 
successive seasons’ activities, are not directly connected. The new tuber is 
linked to the current one only by its stalk, which is given off from the 
stem of the plant usually some distance above the current tuber. Clearly, 
then, the new tuber is produced sunken in the soil because of the downward 
growth of its stalk. Whilst the growth is usually of such an amount as to 
cause the two tubers to lie side by side, this is by no means always the 
case. 
Not infrequently plants are found in the condition shown in Text-fig. 1. 
Here the new tuber is produced at the end of a relatively short stalk, and is 
Text-fig. i. Four-leaved sterile plant showing current tuber buried about 18 mm. New 
tuber formed on short stalk at shallower depth (Oct. 1917). x 3^. 
Text-fig. 2. Two-leaved sterile plant with current tuber 4 mm. below ground-level. New 
tuber formed on long stalk. Sunken about 11 mm. (Oct. 1917). x 3|. 
Text-fig. 3. Single-leaved plant with current tuber partially exposed. New tuber as yet 
scarcely swollen, but sunken to 7 mm. (Sept. 14, 1918). x 3|. 
thus placed vertically in the soil several millimetres nearer the surface than 
the current tuber. 
Or again, specimens may be found in which the current tuber lies just 
below the surface of the soil (Text-fig. 2 ) or even partially exposed (Text- 
fig. 3). Here the new tuber is produced at the end of a relatively long 
