418 BOTANICAL GAZETTE — [JUNE 
In the later part of the rainy season the emptied tuber- -portion 
dies off with all the roots, and the following year the new tuber 
sends up its leaf about 1™ away from the mother plant. The 
formation of horizontal contractile roots seems to repeat itself 
several times in the same individual. 
This mode of loosening crowded colonies by the action of 
horizontal roots occurs, according to Kerner von Marilaun (Plant 
Life 2:769. 1891), also in Muscari racemosum and Ornithogalum 
nutans. 1 have not yet had an opportunity of seeing it in these 
species. But it is by no means a frequent phenomenon, and 
does not occur at all in most of the bulbous plants, as Kerner 
assumes in the quoted passage. From my own experience, con- 
_tractile roots of strictly horizontal direction seem to be very 
fare, and therefore their occurrence in Brodiaea is the more 
noteworthy. — 
Bee Reviewing the ten species examined, we can state that, 
3 although they are geophilous herbs of similar organization, they 
nevertheless show extremely different modes of burying them- 
selves. From this point of view we may arrange these — 
in three groups: 
The first group includes Clintonia, Prosartes, and Fritillaria. 
n these the rhizome alone, by its movement of growth, deter- 
mines the location of the plant in the earth. It develops hori-_ 
n ind is not influenced in a mechanical way by the doa 
contractile. a 
group is formed by Lita: Scoliopus, and Tril- . 
e growth of the horizontally developing rhizome 
sina ch smaller degree the location of the plant. — 
. influence of the contractile Posts in — 
