LEITNERIA FLORIDANA. 83 
protoplasm, sieve tubes should be found.* Thetwo systems 
thus map out the bundles, in cross-section, into a series of 
quadrangles. 
Throughout, like the wood, the cortex is destitute of 
secretion passages. The cork, which is formed immedi- 
ately next the epidermis ¢ during the first summer, cuts off 
a bark which does not become very thick, and is inter- 
ruptedly stratified by the intercalation of masses of con- 
densed cells between layers of more open cells.{ Grit 
cells are entirely absent, and I have not satisfied myself that 
the primary cortical parenchyma is added to below the 
cork by the formation of phelloderm from the inner limits 
of the latter. 
In sections just below the nodes, fibro-vascular bundles 
may be found running obliquely upwards through the 
cortex, from the xylem to the leaf scars. The tracheary 
elements of these bundles are spirally marked as in the 
primary xylem next the pith, and they are unaccompanied 
by secretion passages. So far as I have observed, their 
transit through the cortex is effected in a vertical distance 
little greater than the thickness of the latter, so that they 
* Van Tieghem and Lecomte (J. c. 181) speak of these tangential bands 
as consisting of ‘tubes criblés,’’ and it is clearly in them that the sieve 
tissue should be found; but notwithstanding repeated examination of 
sections from fresh, dry and alcoholic material, which had been subjected 
to treatment which renders the sieve tubes of Tilia, Magnolia, Ulmus and 
other trees very evident, I have quite failed to demonstrate sieve plates 
in the cortex of this species. 
+ So far as can be judged from specimens still retaining the epidermis, 
but with fifteen or twenty layers of cork cells, the first subepidermal 
layer of cortical cells becomes active as phellogen; but as this is formed 
in the early summer of the first year, while I have been able to study only 
very young shoots and those which had ended the season’s growth, I 
have been unable to get a preparation showing the first segmentation, 
which would afford conclusive information on this point. 
¢t This is to be compared with the annual cork layers described for 
Balsamifluae by Reinsch, Engler’s Bot. Jahrb. xi. 367. 
§ The occurrence of true cortical bundles in various groups of plants 
is discussed by DeBary, Vergl. Anat. 266; Mueller, Engler’s Jahrb. ii. 
449; Gilg, Ber. Deutsch. Bot. Ges. xi. 21; Burck, Ann. Jard, Bot. Buiten- 
zorg, vi. 156; Heim, Thesis, 18, etc. 
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