224 
Notes. 
It may be further pointed out that the dorsal position of the 
sporangia is not quite universal in the Filicinae. Thus, it has been 
ascertained 1 that ventral, as well as dorsal, sporangia are normally 
borne by the sporophyll of Acrostichum ( Olfersia ) cervinum , and the 
same thing has been observed as an abnormality in various other 
Ferns, such as Scolopendrium vulgar Polypodium anomalum , &c. It 
appears also from Goebel's researches 2 that the sporangia of Marsilia 
and Pilularia are ventral. 
S. H. VINES, Oxford. 
OI THE OCCURRENCE OF STARCH IN THE ONION. 
- — The leaves of the onion are known to be somewhat exceptional in 
that they do not form starch in the process of assimilation, glucose, 
which is present in large quantities in the mesophyll-cells, apparently 
taking its place. Many other plants behave in a similar way, the 
chlorophyll-corpuscles of their leaves forming no starch in the normal 
process of assimilation, but by placing the plant or its leaves under 
unusual conditions in connection with its nutrition, starch may, in 
almost every case, be made to appear in larger or smaller quantities. 
Thus in the Musaceae, where oil might seem to take the place of 
starch as a product of assimilation in the mesophyll-cells, Godlewski 3 
has shown that by isolating small pieces of healthy young leaves for a 
few hours in an atmosphere containing from six to eight per cent, of 
carbon dioxide, the mesophyll-cells become crowded with starch. 
Bohm 4 by laying the leaves in twenty per cent, sugar solution 
succeeded in bringing about formation of starch in a number of 
Monocotyledons, Galanthus , Hyacinthus , &c., in the leaves of which 
starch does not normally occur, but which, like the onion, contain a 
great deal of glucose. 
He was, however, unsuccessful with the onion, both when he used 
a twenty per cent, sugar-solution, and in an atmosphere containing 
five per cent, of C0 2 . Schimper 5 , in his account of the formation and 
travelling of the carbohydrate in foliage-leaves, concludes that in some 
1 See Kunze, in Bot. Zeit. 1848 ; Moore, On some Suprasoriferous Ferns, in Journ. 
Linn. Soc. II, 1858 ; Braun, Die Frage nach der Gymnospermie der Cycadeen, 
inMonatsber. d. k. Akad. d. Wiss. Berlin, 1875, p. 352. 
2 Goebel, Entwicklungsgeschichte der Sporangien, in Bot. Zeitg., 1882, p. 776. 
3 Flora, 1877, P- 2I 5 - 4 Bot. Zeit. 1883. 5 Bot. Zeit. 1885. 
