830 



ANNUAL REGISTER, 1809. 



root, that organ possesses, in com- 

 mon with the stem and branches, 

 the power of producing buds, and of 

 emitting fibrous roots, and when 

 it is detached from the tree, the 

 buds ahvays spring near its upper 

 end, and the roots near the oppo- 

 site extremity, as in the cuttings 

 above-mentioned. The alburnum 

 of the root is also similar to that 

 of other parts of the tree, except 

 that it is more porous, probably 

 owing to the presence of abundant 

 moisture, during the period in 

 which it is deposited.* And possi- 

 bly the same cause may retain the 

 wood of the root permanently in 

 the state of alburnum ; fori have 

 shown in a former memoir, that if 

 the mould be taken away, so that 

 the parts of the larger roots, which 

 adjoin the trunk, be exposed to the 

 air, such parts are subsequently 

 found to contain much heart- 

 wood.t 



I would wish the preceding ob- 

 servations to be considered as ex- 

 tending to trees only, and exclusive 

 of the palm tribe ; but I believe 

 they are nevertheless generally ap- 

 plicable to perennial herbaceous 

 plants, and that the buds and 

 fibrous roots of these originate from 

 substances which correspond with 

 the alburnum and bark of trees. 

 It is obvious, that the roots 

 which bulbs emit in the spring, 

 are generated by the sap which 

 descends from the bulb, when 

 that retains its natural position ; 

 and such tuberous rooted plants 

 as the potatoe offer rathera seeming 

 than a real obstacle to the hypothe- 

 sis I am endeavouring to establish. 

 The buds of these are generally 



formed beneath the soil ; but I 

 have shown, in a former memoir, 

 that the buds on every part of 

 the stem may be made to gener- 

 ate tubers, which are similar to 

 those usually formed beneath the 

 soil ; and I have subsequently seen, 

 in many instances, such emitted 

 by a re- produced bud, without, 

 the calix of a blossom, which 

 had failed to produce fruit ; but 

 I have never, under any circum- 

 stances, been able to obtain tu- 

 bers from the fibrous roots of the 

 plant. 



The tube, therefore, appears to 

 differ little from a branch, which has 

 dilated instead of extending itself, 

 except that it becomes capable of 

 retaining life duringa longer period ; 

 and when I have laboured through 

 a whole summer to counteract the 

 natural habits of the plant, a pro- 

 fusion of blossoms has, in many in- 

 stances, sprung from the buds of a 

 tuber. 



The runners also, which, ac- 

 cording to the natural habit of the 

 plant, give existence to the tubers 

 beneath the soil, are very similar 

 in organization to the stem of the 

 plant, and readily emit leaves, and 

 become converted into perfect 

 stems, in a few days, if the cur- 

 rent of ascending sap be diverted 

 into them ; and the mode in which 

 the tuber is formed above, and 

 beneath the soil, is precisely the 

 same. And when the sap, which 

 has been deposited at rest during 

 the autumn and winter, is again 

 called into action to feed the buds, 

 which elongate into parts of the 

 stems of the future plants in the 

 spring, fibrous roots are emitted 



from 



Phil. Trans, for 1801. 



t Ibid. 



