358 MR H. C DAVIE ON 



manner. Gymnogramma Pearcei, Ceropteris calomelanos, and C. calomelanos, var. 

 chrysophylla, show the marginal type in one of its varietal forms (cf. above, p. 352). 

 The marginal type also occurs in Pellsea hastata (Thbg.) Prantl and P. rotundifolia 

 (Forst.) Hk., Cryptogramma crispa (L.) R. Br., and in Cheilanthes argentea (Gmel.) 

 Kze. and C. myriophylla, Desv., var. elegans (PL XXXV. fig. 21). In these Ferns the 

 leaf-trace has a compact mass of tracheides, four-sided and wider on the adaxial than 

 on the abaxial side of the petiole. The margin is simply nipped off to supply 

 the pinnae. 



This form of leaf- trace appears also in Notholsena affinis (Mett.) Moore and N. 

 bonariensis (Willd.) C. Chr., and the pinna-trace departs in the Pellaia- Cheilanthes 

 fashion. But in Notholsena sinuata (Lag.) Klf. the leaf-trace is binary, the adaxial 

 ends of each strand being distinctly hooked. Here the pinna-trace comes from the 

 back of the hook and leaves a fairly long gap in the side of the leaf-trace strand after 

 it has left it. 



Two sharply contrasted types of pinna-supply are seen in Pteris and the genera 

 associated with it. Pteris cretiea, L., P. biaurita, L., and P. umbrosa, R. Br., have 

 an ordinary marginal pinna-supply. But Histiopteris incisa (PI. XXXIV. fig. 15 and 

 PI. XXXV. fig. 16) joins Pteris (Litobrochia) macilenta, A. Rich., and Hypolepis 

 tenuifolia (Forst.) Bernh. in showing a combination of extramarginal and marginal 

 types, the pinna-trace being built up of two parts, one coming extramarginally from 

 the corner of the arch of the leaf-trace, the other marginally from its extremity. 



This can only be related to what appears in the Cyatheaceae, in Aspidium Moorei 

 and in Leptochilus cuspidatus. It bears no resemblance whatever to the process of 

 pinna-supply in other species of Pteris. 



In the Polypodiaceae we have a consistent adherence to the marginal type of 

 pinna-supply. Polypodium aureum, L., P. vulgare, L., P. phymatodes, L., P. 

 brasiliense, Poir., P. Schneideri, hort., Veitch, and Drynaria rigidula (Sw.) Bedd. 

 (PI. XXXV. fig. 20), all have their pinna-traces simply nipped off from the edges of 

 the leaf-trace bundles, and never give any suggestion of an extramarginal tendency. 



Turning to the Eusporangiate Ferns, we find that the Marattiacese stand by them- 

 selves in their method of giving their pinnae a vascular supply. In Angiopteris 

 evecta (Forst.) Hoffm. and in Marattia attenuata, Lab., the pinnae are supplied by 

 several separate vascular strands. In the petiole there is a complete ring of vascular 

 strands near the periphery, while the central portion is occupied, in Angiopteris* by 

 a single wide vascular strand, in Marattia by five or six strands in two groups, four 

 or five strands making a curved set towards the abaxial face of the petiole, and one 

 being situated below them towards the adaxial face. In both Ferns the pinnae are 

 supplied by the strands at the corner of the leaf-trace nearest to the pinna, by one or 

 two strands from the abaxial and adaxial edges of the peripheral set, and by one 

 strand cut off' from the strand or strands in the central position (text-figs. 4 and 5). 



* In rather small leaves. 



