1Fronds pinnate or bipinnate, or elongate and lobed to a winged rachis
1'Fronds simple, not elongate if deeply lobed
2Rachis not wholly winged
2'Rachis wholly winged (also part of stipe) or the wing not quite continuous in mature plants
3Suprabasal pinnae deeply lobed or pinnate in fronds of mature plants
3'Suprabasal pinnae, if any, entire or nearly so in fronds of mature plants; pinnules, if any, narrow, entire or nearly so
4Rachis very dark and at length glossy
4'Rachis not very dark nor at length glossy
5Sori small, irregularly scattered
5'Sori larger, in one row on each side of main veins or of costules near apices of pinna-lobes
6Indusia small; sori not confluent
6'Indusia lacking; sori sometimes confluent
7Thick hairs on upper surface confined to sinuses
7'Thick hairs between veins generally on upper surface
8Lobes of basal pinnae deeply lobulate
8'Lobes of basal pinnae entire or nearly so
9Suprabasal pinnae shallowly lobed apart from the acute basal lobes
9'Suprabasal pinnae deeply lobed with acute to acuminate lobes
10Basal pinnae of largest fronds 30 cm or more long bearing at most 1 pair of pinnules; suprabasal pinnae lacking pinnules
10'Basal pinnae of largest fronds less than 30 cm long, bearing 2 pairs of pinnules; 2 pairs of suprabasal pinnae each with 1 pair of pinnules.
11Basal pinnae to 30 cm long; lower surface of costae and veins bearing hairs more than 0.5 mm long
11'Basal pinnae to 60 cm long bearing a pair of stalked pinnules; all parts of lower surface bearing minute hairs with spherical tips
12Fronds strongly dimorphous; sterile pinnae broad and shallowly lobed
12'Fronds not strongly dimorphous; pinnae deeply lobed
13Sori all near margins of pinna-lobes
13'Sori mostly not near margin
14Some sori on free veinlets in areoles, or on branches of free veins near apices of pinna-lobes
14'Sori all on connected veins
15Basal pinnae to more than 30 cm long; lobes of upper pinnae acuminate and deeply lobed
15'Basal pinnae shorter, lobes of upper pinnae obtuse, at most crenate
16Basal scales 7 × 1.5 mm, thin, light brown; lamina very firm.
16'Basal scales to 15 × 1 mm, firm, dark; lamina thin, translucent
17Sori indusiate; basal acroscopic lobes of pinnae not longer than the next lobes.
17'Sori exindusiate; basal acroscopic lobes of pinnae much elongate
18Thick hairs lacking between veins on upper surface; indusia glabrous 40. T. keckii b. Thick hairs present between veins on upper surface; indusia fringed with hairs
19Basal pinnae bearing narrow pinnules
19'Basal pinnae lacking free pinnules
20Caudex long-creeping; lamina to 80 cm long
20'Caudex short, erect; lamina much shorter
21Lamina to 25 cm or more long; pinnae 2-4 pairs, pinnules entire or minutely denticulate; rachis hairy on upper surface
21'Lamina to 10 cm long; pinnae 1 pair, deeply crenate-lobate, each with 1 pinnule; no hairs on rachis
22Distal parts of lower pinnae entire; almost all sori in 2 rows between main veins
22'Distal parts of lower pinnae irregularly obliquely lobed; sori small, numerous, irregularly scattered
23Fertile pinnae much contracted, covered beneath with sporangia
23'Fertile pinnae not very narrow, most sori distinct
24Pinnae of fertile frond 1 pair, c. 1 cm long
24'Pinnae of fertile frond several pairs, much longer
25Fertile pinnae to 1.5 cm wide, sterile to 3.5 cm
25'Fertile pinnae much wider where fronds are dimorphous
26Pinnae (including basal ones) all narrowly decurrent
26'Pinnae not all narrowly decurrent
27No buds at bases of pinnae; indusia very small, not distinct on mature sori
27'Buds present at bases of pinnae; indusia distinct
28A large acuminate lobe present on acroscopic base of pinnae, at least on basal ones
28'Acroscopic basal lobes lacking
29Sori irregularly arranged, some elongate or coalescent
29'Sori not coalescent, or if so in 2 rows between main veins
30Suprabasal pinnae narrowed at their bases
30'Suprabasal pinnae with broadly rounded to cordate bases
31Sori mostly not confluent, some with small indusa; buds present at bases of upper pinnae
31'Sori mostly confluent, no indusia, no buds
32Many sori running along veins; no indusa
32'Sori all on free veinlets in areoles, none linear; small indusia present
33Sori near margins only; pinnae 1 pair
33'Sori not only near margins; pinnae more than 1 pair
34Sori in 1 row on each side of main veins, or with occasional additional ones es pecially near costae
34'Sori not only in 1 row on each side of main veins
35Sori on free veinlets in areoles
35'Sori not all on free veins in areoles
36Sori much elongate
36'Sori not or little elongate
37Areoles in fertile pinnae each with a single veinlet
37'Aréoles in fertile pinnae mosdy containing forked veinlets
38Basal pinnae unlobed; indusia not peltate
38'Basal pinnae lobed; indusia peltate
39Stipe and rachis dark and glossy
39'Stipe and rachis not dark and glossy
40Pinnae not auricled on acroscopic side
40'Pinnae auricled on the acroscopic side
41Pinnae commonly 25 cm long; basal scales 1.5-3 mm wide.
41'Pinnae to 17 cm long; basal scales not over 1 mm wide
42Basal scales not contorted; middle pinnae to 3 cm wide
42'Basal scales much contorted; pinnae to 5 cm wide
43Basal pinnae bearing at least 1 large basiscopic lobe
43'Basal pinnae unlobed
44Bases of pinnae broad, cordate on basiscopic side
44'Bases of pinnae subequally cuneate
45Fertile pinnae 3-5 cm wide; indusia not peltate
45'Fertile pinnae 2-3.5 cm wide; indusia peltate
46Fronds with a simple or trilobed apex and 1 pair of unlobed pinnae
46'Fronds mostly with several pairs of pinnae, basal ones lobed
47Sori regularly spaced and separate
47'Sori irregular, often ± elongate and confluent
48Indusia large; bases of pinnae cordate on basiscopic side
48'Indusia very small; bases of pinnae cuneate to rounded both sides
49Stipes not very dark; basal pinnae with 2 basiscopic lobes.
49'Stipes nearly black; basal pinnae with one large basiscopic lobe
50Pinnae to 2 cm wide, no buds on rachis; sori often elongate or confluent parallel to main veins
50'Pinnae wider; buds present at bases of pinnae; lower sori elongate at right angles to main veins
51Caudex erect or suberect; stipes tufted
51'Caudex long-creeping, fronds seriate
52Pinnae commonly 5 cm or more wide
52'Pinnae not or little over 2 cm wide
53Buds present on upper surface of midrib of apical lamina or at bases of pinnae.
53'Buds lacking in either position
54Pinnae to 4 pairs; scales not twisted, few persistent above bases of stipes
54'Pinnae 1 pair; scales twisted, to 20 mm long, many persistent above bases of stipes
55Pinnae 1 pair
55'Pinnae to at least 3 pairs
56Rachis very dark and glossy; apical lamina 5-lobed
56'Rachis otherwise; apical lamina 3-lobed
57Bases of pinnae narrowly cuneate
57'Bases of pinnae rounded to subcordate on basiscopic side.
58Pinnae to 5 pairs
58'Pinnae 1 or 2 pairs
59Buds present on upper surface of costa of apical lamina; small indusia present
59'Buds lacking; no indusia
60Pinnae commonly to 3 cm wide, their bases narrowly cuneate
60'Pinnae commonly 6 cm wide, their basiscopic bases rounded
61Pinnae or pinna-like lobes of fertile fronds 3 mm wide, wholly covered beneath by sporangia
61'Pinnae or pinna-like lobes of fertile fronds much wider; sori distinctly separate.
62Rachis-wing not quite continuous; one pair of pinnae present.
62'Rachis-wing quite continuous, decurrent below lowest lobes
63At least the sori remote from costae in 1 row on each side of main veins; indusia conspicuous
63'Sori otherwise arranged; indusia in most cases small or lacking
64All sori in a regular row on each side of main veins
64'Some additional sori, inegularly shaped and arranged, present between the two rows near the costa. Hybrid of 58. T. repanda and 101. T. hilocarpa
65Unwinged stipe very short, winged part broad; lobes of lamina well-spaced
65'Unwinged stipe longer, upper part of wing not broad; lobes of lamina not widely spaced
66Fertile lobes of lamina to 20 × 2 cm. Hybrid of
66'Fertile lobes of lamina to 30 × 6 cm
67Many sori ± confluent
67'Sori not confluent
68Sori indusiate, confluent ones a minority
68'Sori exindusiate, confluent ones many, irregular
69Indusia large with stiff hairs on them
69'Indusia not thus hairy, small or lacking
70Sori very numerous, each consisting of few sporangia; lower surface between veins hairy throughout
70'Sori larger; lower surface not hairy
71Sori indusiate; indusia small but conspicuous
71'Sori exindusiate or with occasional rudimentary indusia
72Wing continuous throughout rachis and also most of the stipe; no buds
72'Wing formed by narrowly decurrent bases of pinnae, not continuous on mature plants; buds present on rachis near pinna-bases
73Lobes of frond narrowly acuminate
73'Lobes of frond abruptly short-acuminate
74Fronds simple with a broad, often cordate base, entire or variously lobed
74'Fronds simple, in most cases unlobed, narrowed towards base
75Lamina ± deeply lobed
75'Lamina entire or crenate
76Sori distinctly and persistentiy indusiate
76'Sori exindusiate, or indusia minute
77Lamina hairy on all parts of lower surf ace of fertile fronds
77'Lamina of fertile fronds glabrous on lower surface
78Apices of lobes obtuse
78'Apices of lobes acuminate
79Sori near margin only
79'Sori generally distributed on fronds of mature plants
80Stipe to 5 cm long; fronds not dimorphous; indusia bearing hairs
80'Stipes to 20 cm long; fertile fronds contracted indusia not hairy
81Fronds trilobed, lateral lobes lacking basal lobules
81'Fronds 5-lobed, or 3-lobed with basiscopic lobules on lateral lobes
82Lateral lobes acuminate, similar in shape to apical lamina
82'Lateral lobes very short, abruptly acute
83Lamina to 19 cm long; scales hair-pointed
83'Lamina to 28 cm long; scales not hair-pointed
84Sori small, nearly all discrete, rarely coalescent, sometimes with small indusia
84'Sori often elongate along veins, exindusiate
85Sori indusiate
85'Sori exindusiate
86Both surfaces covered with short erect hairs
86'Both surfaces glabrous
87Surface between veins densely hairy on both sides
87'Surface between veins glabrous on both sides
88Free included veinlets present in areoles; sori mostly punctate.
88'Free veinlets rare in costal areoles; sori mostly elongate
89Fronds, both sterile and fertile, sometimes deeply lobed; sterile fronds hairy on veins beneath; simple fertile fronds and the lobes of others commonly 3 mm wide
89'Fronds, both sterile and fertile, unlobed (margins at most sinuous), sterile fronds glabrous beneath, fertile commonly 8 mm wide