certain Species of the Genus Chris tisonia. 1 1 9 
usually, into two or more diverging bundles, which dip away 
into the cortex. These ‘ proteid-bundles,’ from the above 
description of their structure, perhaps act as storehouses 
for the spoils of the haustorium. By traversing the greatly- 
enlarged cortex in all directions they aid in distributing the 
nutriment through the tissue of the tuber so formed, thus 
supplying the young lateral roots and stems, which so fre- 
quently have their birth in this organ, with abundance of 
food-substances. The xylem of these bundles eventually 
unites with that of the root-cylinder, which— so filled does 
the tuber become with the ‘ proteid-bundles’ — is often scarcely 
distinguishable in some obscure corner. The tuber thus 
becomes the most important centre of the plant, as the place 
of origin of the haustorium (which I am about to describe), 
the storehouse of the food-substances derived by its means? 
and the birthplace of many young roots and stems. 
The haustorium is of exogenous origin, being formed by 
a superficial outgrowth from the tuber. The Bamboo-root 
may be attached for about an inch along the surface of 
a tuber (Fig. 3), several haustoria being sent into it. Most 
frequently it was found attached at a single narrow point with 
a single haustorium attacking it. The cells of the external 
layer of the root adjacent to the haustorium, or those at all 
contiguous to the host-root, some of which are produced into 
papillae, or grow out together to form multicellular protu- 
berances, have, usually, thick outer walls of a dark-brown tinge. 
They serve to attach the root of the parasite to that of 
the host. 
The lateral and apical cells of the haustorium have purple 
contents and conspicuous nuclei, and are very active in dis- 
solving the cortical cells of the host ; the latter, surrounding 
the haustorium, are often densely filled with starch-grains ; 
these also occur in numbers in the cortical cells of the 
haustorium, and also become stored up in the tuber. The 
xylem of the haustorium consists of slender, narrow, spirally- 
thickened elements ; surrounding these are slightly elongated 
cells with dense protoplasmic contents and very prominent 
