190 PHILOSOPHICAL NOTES ON 



taken as a bract-like appendage, as if the minute nodule were an 

 abortive bud. The underground shoots or stems of the vetch at 

 their nodes developed roots or trifid bracts (two stipules and an 

 abortive leaf ?) indifiPerently, although the above-ground stem never 

 develops roots at its nodes. I also observed that the roots on the 

 underground stems had, at their base, a cup-like appendage, which 

 may, perhaps, be the fusion of abortive bud-scales, like the in- 

 teguments of the seeds. There appears to be room for some 

 interesting experiments in connexion with these wild vetches. A 

 hundred or more seeds might be sown in as many small pots, one 

 seed in each. After germination the earth might be carefully 

 shaken off, and the root of each examined at intervals of a few days 

 or so, with the view of ascertaining the relation of the underground 

 buds to the roots. Possibly the root-buds might not be given off 

 till the green stem and leaves died off, and the warmth of the 

 returning spring stimulated the root into life again. This, how- 

 ever, might possibly be imitated by artificial heat. In such 

 experiments it might also be possible to obtain some clue as to the 

 nature of tlie nodules on the roots of the leguminiferse.* My 

 observations were made on the roots of the wild vetch of the 

 gardens, and it was impossible to ascertain whether the plants were 

 seedlings or the buddings of bits of roots left in the ground from 

 previous weedings, so that what I said in this connexion may be 

 worthless. 



8. In the underground shoot of a potato I saw buds with a 

 branched root on each side of the bud, like stipules, the bud 

 seeming like an abortive leaf. The shoot itself ended in the usual 

 tuber. Another underground shoot of the potato had nodes, which 

 gave off a bract subtending a developed bud, with a root on each 

 side. Other nodes had a third root. All the terminal buds were 

 bent backwards, like the barb of an arrow, apparently for easy 

 progress through the soil. In the potato, some of the underground 

 shoots develop a tuber at their extremity, and all the " eyes " are 

 gathered there, while the pedicel of the tuber is a long bare inter- 

 node. In other cases the long thin pedicel has buds on it. Other 

 shoots have buds and roots at every node, but do not develop 

 tubers. Then, when they reach the surface, they develop leaves 

 only. I have seen as many as six tubers emerge from a single node, 

 and many roots surrounding them, as if that point were a fusion 

 of nodes. At other times every bud of an underground branch is a 

 tuber. 



9. In the underground stem of the horse-radish the bracts 

 enclose a bud, on each side of which a root emerges. Sometimes 



* It is stated elsewhere these nodules are considered as products^of micro- 

 organisms. 



