444, MR. G. BREBNER ON THE 
On the Mucilage-Canals of the Marattiacee. By GroRGE 
Bresyer, late Marshall Scholar in Biological Research, 
Royal College of Science, London. (Communicated by 
D. H. Scorr, M.A., Ph.D., F.L.S.) 
{Read 15th March, 1894.] 
(Pirate XXXVII.) 
Durty the course of an investigation of the comparative anatomy 
of the frond in the Marattiacee—the results of which are yet to 
be published—the mucilage-canals were seen to be well developed 
and, from their prominence in all the species examined, attracted 
special attention. Consultation of the literature revealed that, 
according to the most recently published work on the subject, 
these canals were considered to be lysigenous in origin—that is to 
say, the secretion was believed to be produced at the expense of 
the original protoplasmic body of certain early specialized cells, 
the cavity arising by the subsequent solution of their walls. R. 
Kihn, in his valuable contribution to the anatomy of the Marat- 
tiacee etc.*, came to that conclusion f, and his results appear to 
have been generally accepted, as they seemed to be conclusive 
for the cases examined by him. They were obtained from an 
examination of the roots of Kaulfussia, Angiopteris, and Ma- 
rattia. Previous observers ¢ had given varying accounts of the 
development, some considering the canals to be schizogenous— 
2. e. resulting from the separation of the walls of special meri- 
stematic groups of cells at or near the centre of the group; the 
meristematic cells themselves being differentiated as a secretory 
epithelium—others holding them to be Jysigenous in origin; but 
no very thorough examination seems to have been made in this 
group of plants previous to Kiibn’s work. 
The adult condition of the canals in the frond of all the species 
* “Untersuchungen iiber die Anatomie der Marattiaceen und anderer 
Gefasskryptogamen,” Flora, 1889. 
Tt Loe. cit. p. 481. 
t H. Karsten, “ Die Vegetationsorgane der Palmen,” Schriften der konig- 
lichen Akademie der Wissenschaften, 1847, p. 1382. Vriese et Harting, ‘ Mono- 
graphie des Marattiacées,’ 1853, p. 52. Wigand, “ Ueber die Desorganisation 
der Pflanzenzelle etc.,” Jahrb. fiir wissensch. Bot., Bd. iii. 1863, p. 150. Frank, 
“Ueber die anatomische Bedeutung der Entstehung der vegetabilischen 
Schleime,” Jahrb. fiir wissensch. Bot., Bd. v. 1866-1867, p. 183. Russow, 
‘Vergleichende Untersuchungen,’ 1872, p. 106 et seg. De Bary, ‘Comparative 
Anatomy of the Phanerogams and Ferns,’ Engl. Ed., 1884, p. 204. 
