Noteworthy anatomical and physiological researches. 
The function of the secondary tissues in arborescent 
monocotyledons.! 
The secondary growth in the aerial and terrestrial stems of 
the arborescent’ monocotyledons has already been studied by 
various authors, as for instance: Karsten, Millardet, Mirbel, 
Nigeli, Réseler and Wossidlo®, These investigations have 
been mostly restricted to the mere origin and development of 
the secondary meristem, while the study of the function of 
this tissue has been rather neglected. 
The few authors, in whose works mention has been made of 
function, agree, however, in considering the secondary tissue 
as giving rise to a supporting apparatus for the stem, which 
often attains a considerable size in the Liliacez, for instance, — 
Dracena and Cordyline. 
The structure of monocotyledons in which a secondary 
growth takes place exhibits two characteristic cases: the cells 
main thin. There is no doubt that the first case shows 
function of support, while in the other case an entirely differ | 
ent and highly important function is attributed to this thin 
walled parenchyma. In Cohnia flabelliformis, for tmstanct 
the rhizome consists almost entirely of unlignified secondafy 
parenchyma. These cells contain a considerable quantity of 
a fatty oil, which constitutes an important nutritive depost 
especially for the development of adventitious buds. It 
otherwise rare to find such deposits of fatty oils in the 
rhizomes. 
A similar thin-walled parenchyma of secondary origin wii 
also observed in Vucca gloriosa, especially in the rhizome 
the cell-content was in this case a kind of sugar. Dioscoré# 
sativa shows the presence of broad layers of secondary tie 
sues, which form the principal element of the rhizome, a$ de 
scribed by De Bary’ as characteristic of other Dioscoreace® 
The cells contained here large deposits of starch. 
*De Corvemoy, Sur le réle des tissus secondaires A réserves des monocotjle 
dones arborescentes (Comptes Rendus 117: 1 32. 1893). 
*For citations see the original paper. 
*De Bary, Vergleichende Anatomie der Vegetationsorgane der 
men und Farne 60. Leipzig, 1877. 
‘s 
Phanerogy 
