364 Dr. A. Braun on the Vegetable Individual. 



axis, from w hose axils the flowers rise and form a third kiud of 

 shoot. 



On examiiiini; closer into the real orijjin of these differences, 

 we tind their ground to be a partition of the diff'erent steps of 

 the metamorphosis (of the formations) among difl'erent shoots. 

 True, there are many plants which go through the whole series 

 of formations, from the inferior* and the foliaeeous formations 

 up to flower and fruit ; but the cases are very numerous in which 

 this does not take place, and in which the single shoot is not 

 able to produce all the formations. Thus there are shoots which 

 are only able to realize the lower steps, and never attain to flowers 

 and fruit ; while others overleap all the inferior degrees and com- 

 mence innnediately with the formation of flowers. Hence, on 

 the one hand, we see the metamorphosis interrupted, a stoppage 

 taking place at a determinate step ; on the other, the metamor- 

 phosis attained by passing over the intermediate steps. Still 

 more remarkable are the cases in which the retardation is not 

 merely an interruption at a determinate step, but appears as a 

 real retrogression in the metamorphosis, whereby an alternate 

 rise and fall — an oscillation — usually takes ])lace, which may at 

 last pass over in victorious progress to the formation of flower 

 and fruit ; though in most instances it prevents the shoot in 

 question from ever attaining its end. HcUeburiui niger is an ex- 

 ample of the first case ; for after many years of inferior- and 

 foliaceous-leaf formation, at last it attains suj)erior leaves and 

 fruit by overleaping the formation of foliaceous-leaves which 

 until then had prevented its further progressf. Many of our 

 trees with true foliage present examples of the second case. 

 Their branches commence with bud-scales (inferior-leaves), the 

 succeeding foliaeeous branch ends with a terminal bud (thus 

 falling back to inferior-leaf formation), and in the next period of 

 vegetation they rise again to foliaceous-leaf formation i, — as in 



* On the terminology' of the leaf-formations, see Wydler, Bot. Zeit. 

 1844, .'^Htes Stiick, and A. Braun, Verjiingung, p. 66. (Henfrey's Transl. 

 Ray Soc. ISo.':!, p. 62.) 



t Analojrous cases occur in the branches in ^Esculus and many Maples 

 which attain to flowers. Among herbaceous ])Iants Anemone nemorosa and 

 Asariim Ettropeetim also belong here, and esj)eciaily remarkable is the Tulip, 

 the ])lants of which, not yet ripe for flowering, annually develope one single 

 foliaeeous leaf, followed by a central biul hidden in the middle of the bulb 

 and composed of several infenor-leaves. 'I'his bud preserves this position 

 in bulbs deep in the ground, but in those nearer the surface it is, as it were, 

 led out of the centre of the bulb, and sinks deeper into the earth, causing 

 an indentation of the surrounding base of the preceding leaf in form like a 

 spur, boring through the old Ijulb and j)enetrating vertically into the 

 ground, and at the same time sinking itself into a deeper stratum with the 

 spur ; — an arrangement explained, but not with sufficient clearness, by 

 Henr} in Nov. Act. Nat. Cur. vol. xxi. p. 275. t. 16 & 17. 



t In such librations. of course, the formation of the flower can onlv be 



