Br. A. Braun on the Vegetable Individual. 353 



owes none of its essential parts to the branches^S 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 riso, not from the 

 surface ])ut 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. Schimper J, in a Report on 

 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 7^oot, 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<2\\. Shoots 

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

 formation from leaves has often been discussed and described in 



* Unger, Ueber denBau des Dicotyledonen-Stammes (1840), pp. 65, G6. 



t llecherches sur I'orig. des bourg. adv. Ann. des So. Nat. viii. (1847) 

 p. 268. 



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



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

 cially on the first internode under the cotyledons, as Roeper (Enum. 

 Eupliorb. 1824) first showed in Eujjhorbia, and Bernhardi in the germ 

 of Linarice. A specimen of Begonia manicata dipetala, cultivated in our 

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

 B. pliyllomaniaca of Mju-tius, presents the case of a plant which produces 

 a multitude of shootlets in the whole leaf-region ; they arise from the sappy 

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



II According to Rheede, Corypha umhraculifera sends forth root-shoots 

 when the stem dies oif, after the fruit has ripened. ^ "* 



% I have often observed them in Liiiaria vulgaris, Helichrysumarenariuf^fi 

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



