CH. XVIII] 



BOTRYOPTERIDEAE 



Fig. 311. Botryopleris mi/iosa. Transverse seclion of stem and leaf-bases, px, pro- 

 toxylem-group in stele; /./.i, leaf-trace in attached petiole; l.t.^, leaf-trace in 

 cortex; rt, roots, some in connection with stem, and others free. ( x about 8.) 

 S. Coll. 2314 (G.T.G.). (After Scott.) 



B 



¥\g. 312. Boiryopteris cylindrica, a form. A, Transverse section, showing imequal dichotomy. 

 In the smaller branch the double protoxylem is still very excentric : in the larger branch 

 there are three protoxylems. A root is being given off from this branch. B, Transverse 

 section of stem and petiole. In the stem there are either two or three internal protoxylems. 

 In the petiole there are two, almost confluent, on the lower (originally adaxial) side of the 

 bundle. In both specimens the delicate outer cortex is almost lost. ( x about 24.) S. Coll. 

 1906. (From photographs by Mr W. Tarns. After Scott.) 



