COURSE OF THE BUNDLES IN THE STEM. 259 



inner ring ; partly sma!I bundles, the origin of which remains to be decided ; these pass 

 close beneath the epidermis, and are connected with one another by oblique branches. 

 A thorough investigation is in progress ^ 



In the Melastomacex the course of the cortical bundles is partly the same as the 

 above, and partly similar to that in Calycanthus. It may here be described in connection 

 with the other peculiarities of arrangement of the bundles in this family (comp. p. 256)'^. 



The stem has four angles, and bears decussate pairs of opposite leaves : those of one 

 pair are either equal, or, as in many Centradenias, of unequal size. Each pair faces two 

 opposed surfaces of the stem : these may be called the surfaces belonging to that pair, 

 and the others the intervening surfaces. In the simplest case investigated the trace of the 

 single leaf which enters the node consists of three bundles, one median and two lateral : 

 in many species it consists of more than three, through multiplication of the lateral bundles 

 on each side. The bundles which enter the stem pass, in many species, directly into 

 the bundle-ring without forming cortical bundles : Sonerila margaritacea, Medinilla 

 farinosa, Sieboldii, magnifica, Cyanophyllum magnificum, Clidemia parviflora, Miconia 

 purpurascens, Lasiandra Hoibrenkii-\ In the other investigated species the median 

 bundle always enters the bundle-ring, usually without, rarely after previously giving off 

 cortical bundles ; the lateral ones either run, as in Calycanthus, down the angles of the 

 stem as cortical bundles, or they enter the ring, after having given off cortical bundles as 

 branches. The cortical bundles are always connected at the node both with one another 

 and with those which pass to the ring, by a transverse girdle of horizontal branches : they 

 run from this to the next lower transverse girdle, and insert themselves on the latter. 

 In the ring the bundles of the trace always pass down through several internodes, they 

 pectinate in various ways with those of lower pairs of leaves, remaining simple, or 

 splitting into shanks. For numerous differences of arrangement according to the 

 number of bundles and the species, compare Vochting, /. c. 



The cortical bundles are always derived, as above stated, from the bundles of the 

 trace. In the simplest case (Centradenia rosea, Fig. 114) they are the lateral bundles 

 of the three-bundled trace. From the base of the leaf one stronger median bundle 

 w,— W4) and two weaker lateral ones enter the node. All the median bundles are arranged 

 in the ring: they pursue an individual course, directly, or with slight curvature at the 

 nodes, through three internodes (two according to Vochting), and then unite laterally with 

 such as come from lower nodes. The lateral bundles give off one branch on each side 

 at the node, which runs transversely through the outer cortex, the one to the out-going 

 median bundle of the same leaf, the other to a similar one, which comes from the 

 iiearest lateral bundle of the opposite leaf. These branches together form the transverse 

 girdle of the node, which girdle is further connected with the out-going portions of the 

 bundles by small branches. From the point of departure of the branches of the girdle 

 each lateral bundle runs perpendicularly through the cortex of the corner of the stem, 

 and inserts itself on the transverse girdle of the next lower node. 



As an example of the other case, i. e. that cortical bundles and transverse girdles are 

 branches of the bundles entering the ring, Osbeckia canescens (Figs. 115, 116) may be 

 described. A strong median bundle nii - ;«4 enters from each leaf, into the corresponding 

 side of the internode, and here descends perpendicularly, in the bundle-ring : in the 

 next lower node it splits into two shanks (wj and wj), which enclose between them the 

 united lateral bundle, which there enters the stem: these shanks may be further followed 

 down three internodes. A strong lateral bundle passes from each leaf almost horizontally 

 through the cortex into the middle of each of the intervening sides : it here unites with 



* E. Zacharias, Ueber die Anatomic des Stammes der Gattung Nepenthes, Stiassburg, 1877. 



- Vochting, Bau, &c. d. Melastomaceen, in Hanstein's 13ot., Abhandl. III. Compare also 

 Criiger, Botan. Zeitg. 1850, p. 178. — Sanio, Ibid. 1865, p. 179. — Hildebrand, Begoniaceenstamme, p. i. 



^ The names quoted are partly derived from Vochting's work, and partly garden names, for the 

 correctness of which I will not answer. 



S 2 



