. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. COURSE OF THE BUNDLES IN THE STEM. 257. Fig. 113. — Casuarina muricata. Scheme of the course of the vascu- lar bundles in the median longitu- dinal section of a young branch. I—4 successive whorls of leaves; bundles of whorl, 2 ending in node <7, 3 in *. 4 in c. &c. into the periphery of the stem, and there runs, parallel to it, in the cortex as far as the next node: it then curves inwards, and ranging itself with those of the same whorl of leaves around a narrow cylinder of p
. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. COURSE OF THE BUNDLES IN THE STEM. 257. Fig. 113. — Casuarina muricata. Scheme of the course of the vascu- lar bundles in the median longitu- dinal section of a young branch. I—4 successive whorls of leaves; bundles of whorl, 2 ending in node <7, 3 in *. 4 in c. &c. into the periphery of the stem, and there runs, parallel to it, in the cortex as far as the next node: it then curves inwards, and ranging itself with those of the same whorl of leaves around a narrow cylinder of pith, it descends per- pendicularly through a second internode. At the lower limit of this, i. e. at the 2nd node from the point of exit into the leaf, it is inserted (according to Low with a short fork) on the bundles which here pass out into the cortex. The transverse section of each internode thus shows 2 con- centric circles of an equal number of alternating bundles: the one peripheral, composed of the bundles of the trace of its own whorl of leaves, the other axile (forming the woody ring at a later period), consisting of the bundles of the trace of the next higher leaf. In Begonia angularis Raddi, Hildebrand^ found one bundle in the outer cortex of each of the six angles of the stem. All the six in one internode form together the trace of the next higher leaf, which includes | of the circumference of the stem. They pass perpendicularly downwards in the angles to the next lower node, and here curve into the ring of bundles. Their further course in the latter has not been investigated. Many internodes have less than six angles, and correspondingly fewer cortical bundles: others may be en- tirely without either. The same is the case with Begonia tomentosa, with this difference, that the number of the cortical bundles is 'indefinite' and often very large, while some of them often run through two internodes in the cortex. ylrceuthobium Oxycedri - has decussating pairs of le
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
