Terrestrial ferns of small to medium size. Rhizome short- to moderately long-creeping, solenostelic with a sclerotic medullary strand, or if slender then protostelic with a solid fibrovascular bundle with internal phloem, (Lindsaeoid protostele), bearing basally attached, concolourous, elongate to acicular scales, the scales sometimes uniseriate apically and appearing as hairs. Fronds long-stipitate, the stipe with a single V- or U-shaped vascular bundle, abaxially terete, adaxially grooved upwards, the grooves and edgescontinuous with those of the higher order branches, the lamina leathery, pinnately to tripinnately compound, oblong-lanceolate to deltoid in outline, the apical pinnae gradually reduced, or +/- the same as the lateral pinnae, strongly anadromous, ultimate free segments with a costa or costule, the veins free, simple or forked, terminating short of the margin. Sori +/- submarginal, terminal on a single vein or uniting 2 veins, the indusium attached basally and +/- at the sides, opening towards the apical margin, paraphyses several-celled; sporangia with a triseriate stalk, the annulus longitudinal, interrupted, of c.15 thickened cells. Spores monolete, smooth.
| 1a. |
Lamina simply pinnate with a conform terminal pinna |
2 |
|
Lamina more strongly dissected |
3 |
| 2a. |
Petiole and rachis dark, abaxially +/- sharply biangular, pale-margined, often sulcate; sori close to the margin, mostly binerval, on the acroscopic margin of a serration; margins with a single level of serration. |
T. longipinnulum |
|
Petiole and rachis purplish-brown, terete or abaxially obtuse-biangular, not pale-margined, not sulcate; sori remote from the margin, mostly uninerval, within a crenation; margins with 2 levals of crenation. |
T. melanesicum |
| 3a. |
Primary rachis abaxially sharply carinate; at least a considerable upper portion of the stipe abaxially binangular |
T. denhamii |
|
Primary rachis abaxially terete or biangular, or if obtusely carinate then the stipe not (or only at the apex) sharply biangular |
4 |
| 4a. |
Primary rachis dark, at least at the base; secondary rachises pale; pinnae pinnate-pinnataifid or subbipinnate; sori longest in the direction of the vein |
T. stenocarpum |
|
Primary rachis pale, or if dark then the secondary rachises not abruptly pale; lamina often more incised |
5 |
| 5a. |
All axes, except the primary, green-margined to the base, or almost so (ie. The lamina only once fully pinnate, then pinnatifid; secondary axes abaxially rounded. |
T. buniifolium |
|
Lamina mostly fully bipinnate; secondary rachises, if green-margined, abaxially carinate |
6 |
| 6a. |
Secondary rachises abaxially black, with 2 pale lateral or 1 pale median ridge; lamina bipinnate or almost so, with superficially crenate-lobed pinnules |
T. atratum |
|
Secondary rachises abaxially various, but not black with pale ridges; lamina often bipinnate-pinnatifid |
7 |
| 7a. |
Primary rachis and indusia black; ultimate lobes with very broad and prominent veins occupying 1/3-3/4 of their width |
T. obtusatlum |
|
Primary rachis and indusia pale to dark brown; ultimate lobes with immersed, or if slightly prominent then relatively much narrower veins |
8 |
| 8a. |
Indusia c. twice as long in the direction of the vein as across it, c.1/3 mm across; the margin bordening the apical sorus of the segment usually denticulate; texture herbaceous |
T. denhamii |
|
Indusium wider across the direction of the vein, or if only c.1/3 mm across then +/- isodiametric; the margin bordering the apical sorus entire, or no apical sorus; texture firmer |
9 |
| 9a. |
Larger segments pinnatifid, each lobe with a sorus overtopped by part of the lobe |
T. amboinense |
|
Larger segmetns (except for basal pinnaee) crenate, each lobe with a terminal or subterminal sorus |
T. novoguineense |
