COURSE OF THE BUNDLES IN THE STEM. 



255 



rhizome of Nelumhium speciosum ^ The internode between the latter and the next 

 following scale leaf is elongated (as much as 4 feet), the others are short. The elongated 

 internode (Fig. 112) has six blunt angles, so that when horizontally placed one surface is 

 turned upwards (0), another downwards {u), and one edge to each side right and left. 

 It is traversed by 6 large air-canals (/), corresponding to the angles, one small axile one, and 

 two small ones, corresponding to the upper surface, and in regular cases (slight deviations 

 occur) by about 252 vascular bundles with a perpendicular course, the arrangement of 

 which in the transverse section is according to Wigand as follows. Firstly, an inner system 

 of twelve bundles, disposed in two concentric alternating circles (i and 2) of six each, at 

 equal distances from one another in each circle, in the inmost circle (i) one bundle is 

 opposite the upper, and one opposite the lower surface ; secondly, a middle system, 

 extending to the outer limit of the air-canals : it consists of four concentric rings (circles 

 3-6); in each of the circles 4, 5, 6, one bundle alternates with two air-canals: in circle 3, in 

 addition to the otherwise similar arrangement, there are on each side between each two 



Fig. li'a. — Scheme of the transverse section through the internode of a rhizome of Nelumbium speciosum, 

 after Wigand. o upper, tt lower side ; /air canals. The figures i — ri indicate the successive circles in which the 

 bundles are arranged. The bundles of the circles 3 and 5 have an orientation the reverse of that of the others, 

 which is indicated by direction of the dashes affixed to the round spots. 



lateral lower air-passages three bundles, and on each side between the two lateral upper 

 ones two bundles, that is six more bundles are present than in the other circles : the bundles 

 of four circles, with exception of the last-named six, form regular radial rows. Thirdly, the 

 peripheral system, between the outer side of the air-canals and the surface of the stem, 

 consists of 4-5 concentric circles of bundles (7-1 r), the inmost (7) having 18 bundles in 

 pairs alternating with the radial rows of the middle series and with the air-passages ; 

 the next (8) consisting of 45 bundles, of which two are between the two of one pair, and 



* According to Wigand, Nelumbium speciosum, Botan. Zeitg. 1871, p. 816, &c. See also 

 Trecul, Ann. Sci. Nat. 5 ser. I. p. 162, &c. 



