DESCRIPTION OF ILLUSTRATIONS , ETC. 
47 
Fig. 5. Common Scale Fern ( Ceterach officinaruvi). 
Fig. 6. Common Polypody ( Polypodium vulgare). 
Fig. 7. Wall Rue or Wall Spleenwort ( Asplenium Ruta-muraria). 
Fig. 8. Common Maiden-hair Spleenwort {Asplenium Trickomanes ). 
Fig. 9. b, Sporangium, c, Annulus, d, Spores from different species of fern. 
Fig. 10. a, Showing reniform indusium of male fern, d, Various spores from 
native and foreign ferns, illustrative of their various forms and structure. 
Fig. 11. a, Spore of Pteris aquilina. b, c, Growth of the spore, d, Prothallus, 
or pro-embryo of Pteris, magnified : 1, root-fibres ; 2, antheridia ; 3, same 
after discharging contents ; 4, pistillidia or archegonia ; 5, natural size of pro¬ 
thallus. e, Pistillidium of Pteris, magnified : 1, spermatic filament; 2, embryo- 
sac. f. Development of the embryo of a fern : 1, leaf; 2, root; 3, bud ; 4, leaf¬ 
stalk. g, Young seedling fern, Pteris. h, Antheridium containing spiral sper¬ 
matic filaments, i, A spermatic filament more highly magnified. 
Fig. 12. a, Section of root, Pteris aquilina. b, Scalariform tissue in situ, 
slightly magnified, c, The same tissue more highly magnified. 
Fig. 13. Round-leaved Sundew [Drosera rotundi/olia). 
Fig. 14. Money-wort, Loose-strife [Lysimachia Nummularia). 
SYNOPSIS of the Groups of British Ferns, including 
the Minor Sections. 
POLYPODIACE^E. 
This large group of ferns are chiefly remarkable from their leaves being rolled 
up in a circinate manner whilst the frond is young, and also by the spore-cases 
containing within their structure an elastic ring called the annulus (see fig. 9). 
The following minor sections comprise the order 
Polypodies. 
Round clusters of spore-cases having no special cover, indusium (fig. 10, a) 
(fig- 1). 
Gymnogrammes. 
Linear clusters of spore-cases having no special cover (fig. 2). 
Aspidies. 
Sori, or spore-cases having indusium of a circular form generally springing 
from the back of the veins (fig. 3). 
