Dr. A. Bi-aun on the Vegetable Individual. 353 



owes none of its essential parts to the branches*. This inde- 

 pendence of the branches is shown still more decisively in adven- 

 titious shoots, whose position is not predetermined by the leaves. 

 Originating at a later period, they take their rise, not from the 

 surface but from the cambium layer, — the internal tissue which 

 preserves the faculty of producing new growths. Hence, if they 

 would come to the light of day they must break through the bark. 

 Their origin has been particularly described by Treculf. W. Hof- 

 meister, however, as I have already remarked, succeeded in 

 tracing it in Equisetum back to the first cell, a cell in the interior 

 of the stem. As is the case with axillary buds, such adventitious 

 buds sometimes remain undeveloped for a long time (ten years 

 and more) without losing their vital activity ; a fact to which 

 attention has lately been called by C. Schimpcr j, in a Report ou 

 Exostoses. When this is the case they not unfrequently de- 

 velope into spherical or conical wood-kernels, which continue to 

 exist without any connexion with the ligneous body of the ma- 

 ternal stem ; this is especially the case in Beeches and Poplars. 

 The individual nature of the shoot is confirmed not only by 

 the mode, but by the place of its origin. While the organs of 

 the individual organism — the leaves of the plant — occupy a 

 position determined with geometrical accuracy, shoots, on the 

 contrary, can arise out of almost any part of the plant, — wherever 

 indeed any cambium exists ; and they may be even enticed by 

 art, out of places where they do not usually appear. There are 

 shoots from the stem, the root, and the leaves. In herbaceous 

 stems they appear in situations determined by the leaves (in the 

 axils of the leaves), while they may be found anywhere on old 

 woody stems § as adventitious buds, or on any part of the lig- 

 nified roots of most dicotyledonous woody growths, and even on 

 some monocotyledonous ones, as in Umbraculifer(E\\. Shoots 

 appear less frequently on the roots of herbaceous plants^. Shoot- 

 formation from leaves has often been discussed and described in 



* Unger, UeberdenBau des Dicotyledonen-Starames (1840), pp. 65, (JG. 



t Rccherchcs siu* I'orig. des bourg. adv. Ann. des Sc. Nat. viii. (1H47) 

 p. 2fi8. 



X In Sept. 1852, in the Versaramlung der Naturforscher in Wiesbaden. 



§ llarely scattered shoots appear on the herbaceous stem, and espe- 

 cially on the lirst internode under the cotyledons, as Iloeper (Enum. 

 Euphorb. 1824) first showed in Euphorbia, and Bernhardi in the germ 

 of hinariae. A specimen of Berjonia raanicata dipetala, cultivated in our 

 [Berlin] Botanical Garden, which is probably the same species as the 

 B. phylhiiianiaca of Martins, presents the case of a plant which produces 

 a multitude of shootlcts in the w hole leaf-region ; they arise from the sajjpy 

 stem which is not yet hardened, soon after the fall of the leaves. 



11 According to Rheede, Corypha umhracuUfera sends forth root-shoots 

 when the stem dies off, after the fruit has rij^ened. 



H I have often observed them in Linaria vulgaris, Helichrysumarenariutn, 

 Ann. ^ Mag. N. Hist. Ser. 2. Vol. xvi. 24 



