610 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
cycle in the young fibro-vascular axis of Pter’s aguilina (photograph 1, 
plate 7). After six or more leaf-traces have been given off, the stelar 
tube encloses a core of fundamental tissue. The internal face of the 
young stelar tube is at first devoid of phloém and it is only subsequently 
that it appears, thus recalling the state of affairs described by Gwynne- 
Vaughan in P. japonica and P. tnvolucrata. At this stage the stelar 
tube would be described in accordance with Van Tieghem’s terminology 
as gamodesmic (gamomeristelic) : collateral strands occur even in the 
old stem; such a strand is figured by Kamienski.™ Photograph 8, 
plate 8, shows a transverse section of the stelar system of this species at 
a region where the internal phloém has already made its appearance. 
At 7’, a root is being given off; 7* is a radical stele which has already 
made its exit from the central cylinder ; 7' and 7? are foliar gaps ; oppo- 
site /' may be seen its corresponding leaf-trace. Photograph 9, plate 8, 
is similarly lettered. In this case the leaf-traces corresponding to two 
foliar gaps are to be seen. The stelar system of P.. farinosa is thus 
from the first, a tube, including primarily only a pericycle, and then 
fundamental tissue as well. The tube is, in the beginning, collateral, 
but becomes subsequently bicollateral through the appearance of inter- 
nal phloém. The stelar tube has gaps in its walls above the points of 
exit of leaf-traces. No such gaps occur opposite the outgoing radical 
strands. 
The writer’s examination of the development of P. farinosa leads to 
results similar to those obtained by Gwynne-Vaughan in the case of 
other so-called polystelic species of this genus, vzz., 1. That the stelar 
system in the young plant does not successively bifurcate, giving rise to 
a varying number of steles, as described by Van Tieghem, but from the 
first forms a stelar tube with foliar gaps. 2. That the stelar tube is 
primitively collateral and only subsequently becomes bicollateral; the 
development of the internal phloém would seem to be a compensation 
for the disappearance of secondary growth in the vascular system of 
these peculiar species of Primula. 
HALORHAGIDACE. 
The peculiar conformation of the fibro-vascular system of the genus 
Gunnera has been described by Reinke.” Subsequently the central 
cylinder of G. macrophylla has been somewhat exhaustively studied by 
25. Op. Cit., plate 6, fig. 3. 
26. Morpholog., Abhand. v. Reinke, Leipzig, 1873. 
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