FILICES. 19 



FAMILY yill. 4tsiiiiin<laceae. Ring rudimentary, consisting 

 of a roundisli lateral group of thickened cells only; stomium apical. 

 Indusium wanting. — Engl. & Prantl, 1. c, fig 203; Hk. Bk., 1. c, tab. 

 VIII, fig. 62r, 63&, d. 



h. SERIES II. Exannulatae. Sporangia rather large, without a 

 ring; walls of the sporangia more than 1 cell thick; antheridia 

 immersed in the prothallium, archegonia immersed or nearly so. 

 (Marattiineae). 



FAMILY IX. llarattiaceae. Sori consisting of 6— 60 sporangia 

 which are either free and placed in 2 close rows or concrete in circular, 

 oblong, linear or 2-valved synangia. — Engl. & Prantl, 1. c, fig. 239 ; Hk. 

 Bk., 1. c, tab. IX, fig. 69—72. 

 B. CLASS II. TXJJ3ET«,ITHj^LLOS.^E. Prothalhum white, 



tuberous, hypogeous or immersed in the substratum; antheridia 



immersed in the prothallium ; archegonia immersed or nearly so. 



(OpMoglossineae) . 



FAMILY X. Ophioglossaceae. Sporangia large, without a 

 ring, having walls several cells thick, not garthered in sori but placed on 

 stalked, much contracted, non-foliaceous, spiciform or paniculiform fertile 

 segments originating from the stipe, the base, the centre or the margin 

 of the normal-shaped foliaceous barren segment of the frond. — Engl. & 

 Prantl, 1. c, fig. 259 A—B, 260 F; Hk. Bk., tab. IX, fig. 73—75. 



Key to the families ('). 



Sporangia small, with a wall only 1 layer of cells thick; ring 



present, complete, incomplete or rudimentary, very rarely wanting. 



(Leptosporangiatae). 



b. Sporangia scattered irregularly along the few longitudinal 



veins. VIL Parkei'iaceae. P. 75L 



h.b. Sporangia collected in sori, crowded over the parenchyma or 



placed in close rows, rarely solitary on the veins or scattered 



laxly between them. 



(') The pages mentioned after the names of the families refer to the Handbook, 

 not to this supplement. 



