1974 CLVI. FILICES. [Asplenium- 



22. A. decussatum (decussate), Swartz; Hook. Spec. Filic. iii. '2,10, Syn.. 

 Filic. 243 ; Bmth. Ft. Austr. vii. 751. Trunk very stout, erect, scaly. Fronds 3» 

 to 4ft. long, pinnate, with a tbick smooth rhachis, often proliferous. Pinnae often 

 thick coriaceous, shortly petiolate or attached by the midrib only, lanceolate,, 

 acuminate, 6in. to near 1ft. long, 1 to li-in. broad, shortly dentate or some of the 

 larger ones pinnatifid or almost pinnate. Primary veins proceeiing obliquely 

 from the midrib to the teeth or lobes, with secondary obliquely pinnate yeinlets- 

 often anastomosing. Sori linear, on the secondary veinlets, with the single or 

 double indusium of the section.— Bail. Litho. Ferns Ql. 121 ; Callipteii^ 

 proli/era, Bory ; Bail. Queensl. Ferns, 32. 



Hab.: Eookingham Bay, Jl'. Hill, Dallachy ; Daintree River, Fitzalan ; Bussell Biver;. 

 Bailey. 



Also in tropical Africa, the Malayan Archipelago and Pacific Islanda. 



29. ASPIDIUM, Swartz. 



(The indusium of some species shield-shaped.) 



Rhizome thick and shortly erect or creeping. Fronds once twice or thrice" 

 pinnate, rarely in species not Australian, simple, fiori orbicular, usually small, 

 variously dispersed over the under surface. Indusium orbicular, covering the 

 sorus when young, attached by the centre or by a point or in a sinus on one side, 

 so that when opened all round by the growth of the spore-cases it becomes 

 peltate or more or less reniform. 



A large genus, distributed over every part of the globe, closely allied to Polypoditim, with 

 nearly as great a variety of division and venation of the frond, differing only in the presence of 

 indusium which in several species disappears very early. 



Sect. I. XTephrolepis. — Fronds pinnate, with numerous nearly equal pinnae articulate on a 

 long rhachis. Sori in a regular row close to or not far from the margin. 



PinnsB rather rigid, obliquely truncate or cordate at the base. 



Pinnse rarely above lin. long, obliquely cordate . I. A. cordifoUum. 



PinnsB 2 to 5in., obliquely truncate at the base 2. A. exaltatum. 



PinnsB membranous, narrow and tapering at the base on one side, 

 broadly aurioulate on the other Z. A. i-amosum. 



Sect. II. ItepliroAivLlu.— Fronds pinnate. Pinnte pinnatifid with a pinnate vein leadincf 

 to each lobe, the veinlets under adjoining lobes uniting in a vein leading to the sinus. 

 Lower pinnae scarcely smaller than the others. 



Soi i in 2 rows near the margin of the lobes usually continued into the 



entire part i. A. unitum. 



Sori close to the margins of the lobes and not continued below the sinus 5. A. pteroides. 

 Lower pinnse gradually much smaller and distant. 

 Frbnds rarely above 2ft. long. Lobes of the pinna rather obtuse or 



acute 6. 4. molle. 



Fronds often 4 to 5tt. long. Lobes of the pinnse broad, very obtuse or 



truncate 7. 4. truncaUm. 



Sect. III. Sagrenia. — 

 Fronds deeply pinnatifid or pinnate, with reticulately veined pinnffi . . . 9. A. conflaens. 



Sect, IV. Polysticliuin. — Fronds twice or ihrice pinnate with lobed or toothed segments. 

 Indusium usually peltate. 

 Stipes very shaggy. Segments ovate-lanceolate, prickly toothed, with an 



angular lobe at the base 9. /(. aculeatum. 



Stipes slightly scaly. Segments, lanceolate, pinnatifid or pinnate, the 



teeth mostly aristate 10. A. aristatum. 



Sect. V. Xiastrea. — Fronds twice or thrice pinnate with lobed or toothed segments. Indu- 

 sium, usually reniform, often very small and soon disappearing, iometimes abortive. 



Fronds glabrous or pubescent. Segments acutely toothed or lobed. Sori 



near the midrib . . : 11. ^. decomporitum. 



Fronds villous, 3 to Tin. long 12. ^. acuminatum. 



var. villosum. 

 Segments acutely toothed or pinnatifid. Sori near the margin ... . .13. A. tenerum. 



