DEVELOPMENT OF THE MEMBERS OF ONE BRANCH-SVSTEM. 



165 



I-'IG. \^~,.—Po/yL;oi!atuin 



tltijio 



luiij^L-r rliizonie consistinjj of 



(HI : a front jiicce of a 

 four annual jrrowthb. ^ seen in profile,^ from above; all the adventitious roots have been cut 

 off. their poiition being indicated by the roundish warts. The numbers 1864, 1865, 1866 denote 

 the ycari in which the respective pieces of the sympodium have grown. 



year indicated. In the same manner \\\\\ the bud ;/ + 3 now become further developed ; 

 it springs from the aSil of the leaf, the scar (insertion) of which is denoted by 9". 1 he 

 basal portion of the 

 shoot which proceeds 

 fr/)m it will add a 

 new piece to the 

 sympodium, its ter- 

 minal part will grow 

 upwards and de- 

 velope leaves and 

 flower*;, and will then 

 die off. Just as ;; + 3 

 sprang from a leaf- 

 axil as a lateral shoot 

 from « + 2, so did 

 this also spring from 

 « + r. Each of these 

 shoots produced on 

 its basal portion nine 

 membranous colour- 

 less scale-like leaves' 

 which are still par- 

 tially retained in 

 n + 3, while in «, 

 « + I, and n + 2, only 



their scars are to be seen ; the numbers 1-9 indicate these in each year's growth. The 

 new lateral shoot arises each year in the axil of the ninth and last scale-leaf, the suc- 

 ceeding leaves of which are then foliage-leaves on slender elongated internodes, while 

 those of the basal portion between the membranous scale-leaves become thick and 

 short. The leaves are in two rows on the basal parts, alternately right and left, as 

 may be seen by their scars ; if the position of the ninth leaf of the segment n is called 

 left, then that of the segment « + i is right, that of the segment n + 2 left ; the shoots 

 which continue the syiiipodium are thus again alternately right and left ; and hence the 

 sympodium is in this case a scorpioid cyme. 



It is evident that the processes of growth would remain precisely the same, if, at the 

 close of each vegetative period, after the bud for the next year had attained sufficient 

 vigour, the whole shoot, including its basal portion, had died off and decayed ; then, of 

 course, no sympodium would be formed, but the development of the underground buds 

 would nevertheless be sympodial. This occurs, for instance, in our native tuber-forming 

 species of Ophrys, but with the difference that if a sympodium were actually formed, it 

 would be a hclicoid cyme. The processes in Colchicum are similar but somewhat more 

 complicated. 



The explanation of processes of growth of this nature requires much space, as the 

 above example shows; I must refer therefore to the labours of Irmisch mentioned 

 below 2. Where the leaves are clearly developed in Monocotyledons and Dicotyledons 

 —and it is only in a few forms of inflorescence that this is not the case— it is almost 

 always easy to understand the true nature of a branch-system even without microscopic 

 examination ; because, ^^■ith but few exceptions, the branching is axillary ; the position 



' i NiederbUUter or ' Cataphyllary leaves' of Henfrey; Braun's Rejuvenescence in Nature; in 

 Ray 80c. , Botanical and Physiological Memoirs, p. 4, 1853.] 



■' Irmisch, Knollen und Zwiebelgewachse. Berlin 1850. — Biologie und Morphologie der 

 Orchideen. Leipzig 1853.— Beitrage zur Morphologic der Pllanzen. Halle 1854, 1856.— Papers m 

 the Botanische Zeitung and the Regensburg ' Flora.' [Henfrey, Bot. Gaz. 1850, 1^51.] 



