927
FILICES.
927
| Indusium altogether wanting | 6. Alsophila. |
| Indusium 2-valved, the upper valve continuous with the margin of the frond | 7. Dicksonia. |
| Suborder III. Polypodiaceæ. Sori dorsal or marginal, naked or furnished with an indusium. Sporangia with a short or long stalk, girt by an incomplete vertical ring, bursting transversely. Habit various. | |
| * Indusium present, at least when the sorus is young. | |
| † Sori dorsal or marginal. Indusium opening outwards, or towards the margin of the frond. | |
| Sori globose or oblong, submarginal. Indusium often cup-shaped, attached by a broad base and sometimes by the sides as well | 8. Davallia. |
| Sori subglobose, dorsal, remote from the margin. Indusium ovate-deltoid, membranous, attached by a broad base | 9. Cystopteris. |
| Sori linear, marginal. Indusium linear, membranous, opening outwards | 10. Lindsaya. |
| †† Sori variable in shape, linear to globose, marginal. Indusium composed of the more or less modified edge of the frond, which is reflexed over the sorus, opening inwards. | |
| Sori reniform or globose or oblong, distinct in the New Zealand species. Indusium an altered and reflexed lobe or tooth of the frond, bearing the sorus on its under-surface | 11. Adiantum. |
| Sori subglobose, distinct, in the notches of the ultimate divisions of the frond. Indusium a slightly modified and reflexed portion of the margin of the frond | 12. Hypolepis. |
| Sori subglobose or oblong, often confluent into linear masses. Indusium composed of the modified and reflexed margins of the frond | 13. Cheilanthes. |
| Sori confluent, forming a linear band extending along the greater part of the edge of the pinnæ, placed on the tips of the transverse veins | 14. Pellæa. |
| Sori linear, extending along the greater part of the edge of the pinnæ or segments, placed on an intramarginal longitudinal vein | 15. Pteris. |
| Sori linear, on the contracted pinnæ of fertile fronds differing much from the sterile ones, covering the whole under-surface | 16. Lomaria. |
| ††† Sori linear or oblong, dorsal (or submarginal when the frond is much divided). Indusium the same shape as the sorus, laterally attached to a vein, opening inwards (or towards the costa). | |
| Sori oblong, on short cross veinlets connecting the primary veins, parallel to ihe costa | 17. Doodia. |
| Sori oblong or linear, on the primary veins, oblique to the costa | 18. Asplenium. |
| †††† Sori globose, dorsal. Indusium orbicular or reniform, peltate or affixed by the sinus, opening all round the margin. | |
| Indusium orbicular and peltate | 19. Aspidium. |
