4io 
West.—On the Structure and Devetopment of 
Russow ( 18 ) accepted Frank’s explanation of the development of two 
kinds of canal, which arise by a schizogenous and a lysigenous process 
respectively. 
In the course of his investigations on the anatomy of the Marattiaceae, 
Ktihn ( 13 ) gave an account of the lysigenous development of the mucilage- 
canals in the roots of Angiopteris , Marattia , and Kaidfussia. 
But the first comparative account of the development of the mucilage- 
canals of the Marattiaceae was published by Brebner ( 2 ), who arrived 
at the conclusion that they are schizogenous intercellular spaces, which 
develop much in the same way as the well-known resin-canals of Pinus , 
Hedera , &c. A well-defined living secretory epithelium is generally 
developed around these intercellular spaces. In a more recent communi¬ 
cation ( 3 ) this author still maintains this view. 
Lutz ( 14 ) published a full account of the development of the mucilage- 
canals in Angiopteris evecta and in Marattia fraxinea, var., and attempted to 
reconcile the conflicting statements of the earlier investigators. This botanist 
distinguished between the typical mucilage-canals, which develop schizo- 
genously, and a second type of mucilage-canal, which arises by the solution 
of the terminal parting-walls of rows of tannin-cells. The tanniniferous 
contents of the latter are said to be gradually replaced by true mucilage. 1 
Farmer and Hill ( 9 ), on the other hand, ascribed a lysigenous develop¬ 
ment to the mucilage-canals which occur in the young sporophyte of 
Angiopteris evecta. 
In his well-known memoir on the Psaronieae and Marattiaceae 
Rudolph ( 17 ) alludes to and figures (l.c., p. 196, Taf. iii, Fig. %d) both 
types of secretory tissue described by Lutz. 
Campbell ( 4 ) observed lysigenous mucilage-canals in the stem of 
Danaea elliptica and of Danaea Jenmani , but states ( 1 . c., p. 181) with 
reference to Kaidfussia that the lysigenous origin of the canals is less 
evident than in Danaea , while it is not impossible that they may sometimes 
be of schizogenous origin. 
Charles (6) concluded that the mucilage-ducts in Marattia alata 
originate both schizogenously and lysigenously, generally the former. 
In view of the striking lack of agreement in existing accounts of 
the structure and development of the secretory tissues of the Marattiaceae, 
which suggests variation or vagueness in these structures, a reinvestigation 
of this point seemed desirable, since it might throw some light on the much- 
debated subject of the phylogeny and affinities of this group of Ferns 
(cf. Matte, 15 , p. 20 6 ; Seward, 19 , p. 217), including the interrelationships 
of the constituent genera. 
With this end in view the present investigation was undertaken. 
1 The results obtained by Lutz were adopted by Bitter ( 1 ) in his account of the Marattiaceae in 
Engler and Prantl, Die natiirlichen Pflanzenfamilien. 
