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XX. — Contributions towards a Knowledge of the Anatomy of the Lower 
Dicotyledons. III. The Anatomy of the Stem of the Calycanthacese. 
By Christine E. Quinlan, M.Sc., University College, Cork. Communicated 
by Professor R. J. Harvey-Gibson, C.B.E., D.L., M.A. (With One Plate.) 
(MS. received November 22, 1918. Read January 20, 1919. Issued separately May 21, 1919.) 
The present paper is the third of a series of researches on the anatomy of the 
lower Dicotyledons undertaken with the object of seeing what, if any, aid anatomy 
might give in determining the point of origin of the so-called Monocotyledons. It 
deals more especially with the anatomical and histological peculiarities of the stem 
of the Calycanthacese. 
Historical Summary. 
Mirbel (l), in 1828, drew attention to the occurrence of four cortical vascular 
bundles in the stem of Calycanthus jloridus, L., each consisting of phloem and 
xylem, inversely orientated, and with an arc of sclerenchyma on the outer margin. 
In 1833, Gaudichaud (2) found that, of the three petiolar bundles, the large median 
one enters the normal vascular ring, while the lateral bundles join the nearest 
cortical bundles; and his work was confirmed by Treviranus (4). In 1836, 
Lindley (3), and, later, Henfrey (5), discovered this was common to all the 
Calycanthacese. In 1860, Woronin (6) described the course of the cortical vascular 
bundles and their relation to the foliar bundles, confirming Gaudichaud as regards 
their mode of fusion, and pointing out that, at the node, a series of anastomoses 
occurs : (l) between the central vascular ring and each of the cortical bundles, 
(2) between the two opposite pairs of cortical bundles, (3) between the median and 
the lateral foliars at the base of the petiole, and (4) between the median foliar and 
the cortical bundles of the axis. In 1884, Lignier (7) showed that the median 
petiolar bundle gives off lateral branches which go to form the cortical bundles of 
the internode immediately superior, and pass out at a higher node. 
In 1885, Her ail (8) stated that the peripheral bundles of the stem of the 
Calycanthaceee were pericyclar in origin and eventually become pushed out into 
the cortex, and that the peripheral bundles of each internode supply the lateral 
bundles of the leaves situated at a lower level, the median one coming directly 
from the central cylinder and receiving a branch from the lateral bundles. In 
1887, Lignier denied the pericyclar origin of these bundles and stated that the 
bundles originate, and are always situated, in the cortex. In 1904, Van Tieghem (9) 
held that in Chimonanthus the peripheral bundles were pericyclic, but in all species 
of Calycanthus purely cortical. 
TRANS. ROY. SOC. EDIN., VOL. LII, PART III (NO. 20). 
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