1Glands present between veins on upper surface of pinnae.
1'Glands lacking or rare on upper surface of pinnae.
2Six or more pairs of lower pinnae gradually reduced
2'Transition to reduced basal pinnae (if any) abrupt or subabrupt.
3Sori elongate.
3'Sori not elongate.
4No basal reduced pinnae
4'Basal reduced pinnae present.
5Middle pinnae sessile
5'Middle pinnae with stalks 3-10 mm long
6Sori exindusiate.
6'Sori indusiate.
7Basal veins quite free
7'Basal veins anastomosing.
8Pinnae to 10 x 1.5 cm; reduced pinnae at least 5 pairs
8'Pinnae to 21 x 2.5 cm; reduced pinnae 2-3 pairs
9Reduced pinnae c. 30 pairs
9'Reduced pinnae rarely more than 12 pairs.
10Lower surface of rachis and costae quite glabrous, or with very short hairs on costae only.
10'Hairs present throughout lower surface of rachis and costae.
11Fronds dimorphous; reduced pinnae all minute
11'Fronds not dimorphous; reduced pinnae conspicuous
12Sporangia copiously setiferous, rarely also with a gland.
12'Sporangia usually bearing glands, sometimes with 1-2 setae.
13Pinnae c. 7 pairs, to 13 x 2.7 cm
13'Pinnae, if only 7 pairs, much smaller.
14One pair of veins anastomosing, next pair to sinus-membrane.
14'1½-2 pairs anastomosing, pairs to sinus-membrane.
15Reduced pinnae 0-3 pairs.
15'Reduced pinnae on well-grown plants at least 5 pairs.
16Pinnae not more than 10 pairs, reduced ones usually lacking.
16'Pinnae at least 20 pairs, reduced ones always present.
17Pinnae lobed not more than half-way to costa
17'Pinnae lobed fully
18Pinnae not more than 4 cm wide, their lobes not acute.
18'Pinnae to 7 cm wide, deeply lobed, lobes narrowly acute
19Pinnae crenate to subentire.
19'Pinnae lobed at least 3 towards costa.
20Pinnae subentire; sinus-membrane hardly detectable
20'Pinnae crenate, at least distally; sinus-membrane evident.
21Pinnae to 3.5 x 1.0 cm; reduced pinnae all very small
21'Pinnae (at least sterile ones) to 7 cm or more long, upper reduced pinnae at least 7 mm long.
22Pinnae to 12-15 cm long; sinus-membrane distally widened and translucent.
22'Pinnae to 8 cm lon^; sinus-membrane distally not widened nor translucent
23Bases of pinnae cuneate, not auricled nor dilated; costules at 45° to costa
23'Bases of pinnae truncate, lower ones auricled and dilated; costules at c. 60° to costa
24Aerophores elongate
24'Aerophores not elongate.
25Bases of pinnae, at least lower ones, dilated both sides.
25'Bases of pinnae not dilated.
26Hairs on lower surface of rachis and costae erect, to 1 mm long on sterile fronds
26'Hairs on lower surface of rachis and costae shorter, antrorse or appressed
27Only 1 pair of veins truly anastomosing, second acroscopic vein sometimes touching sinus-membrane.
27'At least 12 pairs of veins truly anastomosing and 1 vein touching sinus-membrane.
28Basal pinnae much narrowed at their bases
28'Basal pinnae not or little narrowed at their bases.
29Reduced pinnae all very small
29'Reduced pinnae to 1.5 cm or more long.
30Hairs on lower surface of rachis and costae less than 0.1 mm long; no setae on sporangia
30'Hairs on lower surface of rachis and costae 0.2 mm or more long; sporangia setiferous
31Pinnae lobed 4 towards costa, lower ones auricled on acroscopic base
31'Pinnae lobed not over I, lower ones not auricled.
32Pinnae lobed fully 2, widest in distal half
32'Pinnae in most cases lobed less than 2, not widened distally.
33Fertile pinnae little more than 2 cm wide; 14-21 pairs of veins truly anastomosing.
33'Fertile pinnae commonly 2.5-3.0 cm wide; 3-31 pairs of veins truly anastomosing
34Reduced pinnae 3-5 pairs, all very small
34'Reduced pinnae commonly 8 pairs or more, upper ones at least 1 x 1 cm, rounded
35Glands present on lower surface of pinnae between veins.
35'Glands between veins on lower surface of pinnae lacking.
36Pinnae 2-4 cm long, 3-4 mm wide, subentire, several lower pairs gradually reduced
36'Pinnae, if subentire, much wider; transition to reduced basal pinnae ± abrupt.
37Sporangia bearing several setae, sometimes also a gland.
37'Sporangia in most cases bearing glands, sometimes a seta with the glands.
38Normal pinnae 3-4 pairs, 11 x 4 cm or larger; reduced pinnae 12-15 pairs
38'Normal pinnae more numerous or smaller.
39Pinnae opposite, 6-7 pairs, 10 x 2.7 cm or larger
39'Not this combination of characters.
40Sori exindusiate.
40'Sori indusiate.
41Pinnae c. 12 x 1.5 cm, lobed over 1/2, reduced pinnae 15 pairs.
41'Pinnae c. 6 x 1.8 cm, lobed less than 1/2; reduced pinnae 2 pairs
42Reduced pinnae 1-2 pairs, normal pinnae 2-4 pairs 3.5 cm long
42'Not this combination of characters.
43Reduced pinnae at least 6 pairs; transition to large pinnae abrupt.
43'Reduced pinnae not more than 4 pairs, transition not abrupt.
44Reduced pinnae 25-30 pairs
44'Reduced pinnae rarely more than 12 pairs.
45Pinnae lobed conspicuously more than 1/2 way to costa.
45'Pinnae lobed about 1/2 or little more deeply.
46Pinnae c. 12 pairs, 12.5 x 2.4 cm
46'Pinnae 25-30 pairs, proportionately narrower.
47Pinnae to 21 x 2.5 cm
47'Pinnae to 16 x 1.5 cm
48Reduced pinnae all small, to 3 mm long
48'Reduced pinnae all conspicuous
49Texture rigid; pinna-lobes dentate at vein-ends
49'Texture thin; pinna-lobes entire
50Pinnae subentire, very narrowly cuneate at basiscopic base
50'Pinnae otherwise.
51Reduced pinnae 0-2(-3) pairs, small, irregularly spaced.
51'Reduced pinnae at least 4 pairs, regularly spaced; transition to normal pinnae gradual or abrupt.
52Basal veins free
52'Basal veins anastomosing.
531 or 2 pairs of pinnae 6-8 cm long and 1 pair very small
53'Normal pinnae several pairs.
54Upper surface of pinnae bearing appressed hairs between veins.
54'Upper surface of pinnae lacking appressed hairs between veins.
55Free pinnae 3-4 pairs below long apical lamina
55'Free pinnae more numerous; apical lamina not elongate.
56Sterile pinnae not more than 3.5 x 1.2 cm.
56'Sterile pinnae to 8 x 1.8 cm
57Hairs on lower surfaces all short and mostly appressed.
57'Hairs on lower surface of rachis and costae erect, to 1 mm long.
58Pinnae 12-15 pairs, 3.5 cm long, symmetrically many-lobed.
58'Pinnae 5 pairs, c. 16 cm long, with few irregular lobes
59Pinnae 7-10 x 1 cm
59'Pinnae not over 5.5 cm long, more than 1 cm wide.
60Pinnae not dimorphous; apical lamina narrow, 10 cm long.
60'Pinnae dimorphous; apical lamina broadly triangular, shorter.
61Aerophores distinctly elongate.
61'Aerophores not or slightly elongate.
62Basal veins quite free, not meeting at sinus
62'Basal veins meeting at sinus, or anastomosing below it.
63Pinnae entire or slightly crenate.
63'Pinnae distinctly lobed.
64Pinnae c. 5x1 cm, distinctly crenate; transition to 15 pairs of reduced pinnae subabrupt
64'Pinnae larger, almost entire; 12 pairs of lower pinnae gradually reduced
65Appressed hairs present between veins on upper surface of pinnae.
65'No appressed hairs on upper surface between veins.
6612 pairs of lower pinnae gradually reduced and 20 pairs of smaller ones
66'Subabrupt transition to reduced lower pinnae.
67Pinnae lobed not or little more than 1/2 way to costa.
67'Pinnae lobed conspicuously more than ½ way to costa.
68Reduced pinnae conspicuous, upper ones 1-3 cm long.
68'Reduced pinnae all very small.
69Pinnae 12 x 1.6 to 20 x 2 cm, gradually acuminate; lower surface of costae glabrous or with sparse short hairs
69'Pinnae to 14x2.5 cm, abruptly short-acuminate; lower surface of costae densely covered with appressed hairs
70Lower surface of rachis and costae almost glabrous
70'Lower surface of rachis and costae bearing hairs to 1 mm long.
71Largest pinnae commonly 15-20 cm long; hairs on rachis pale.
71'Largest pinnae 7 x 1.5 cm; hairs on rachis brown
72Hairs on lower surface of costules antrorsely appressed.
72'Hairs on lower surface of costules not antrorse.
73Sori supramedial; pinnae to 2.5 cm wide.
73'Sori inframedial; pinnae to 1.5 cm wide
74Basal normal pinnae not narrowed at base
74'Several pairs of lower pinnae much narrowed at their bases.
75Reduced pinnae all conspicuous, lowest 5 mm long
75'Reduced pinnae all small, uppermost 5 mm long.
76Dark hairs on both sides of rachis
76'Pallid hairs on both sides of rachis.
77Lowest pinnae little narrowed at base; reduced pinnae evident.
77'Lower pinnae much narrowed at base; all reduced pinnae minute
78Hairs on lower surface of costules copious, closely appressed.
78'Hairs on lower surface of costules short, not appressed.
79Reduced pinnae all very small, basal normal pinnae narrowed at base.
79'Reduced pinnae conspicuous, many 10-15 mm long; basal normal pinnae not narrowed at base
80Pinnae lobed less than ½ towards costa
80'Pinnae lobed about ¾
81Sori indusiate; sporangia glandular, rarely with a seta.
81'Sori exindusiate; neither glands nor setae on sporangia.
82Lowest normal pinnae narrowed at base
82'Lowest normal pinnae not narrowed at base.
83Pinnae thin, lobed to 2 mm from costa
83'Pinnae subcoriaceous, lobed little more than 1/2
84Basal veins both passing to sides of sinus-membrane or uniting just below it, not or rarely forming a distinct excurrent vein.
84'Basal veins uniting to form an excurrent vein, at least near base of pinna.
85Reduced pinnae all with distinct lamina; costules 2.5 mm apart.
85'Reduced pinnae without distinct lamina; costules 4 mm apart.
86Sori supramedial; caudex a long-creeping rhizome
86'Sori medial or inframedial; caudex not long-creeping.
87Pinnae to 2.5 cm long; dark hairs on upper surface of rachis.
87'Not this combination of characters.
88Lower surface of rachis glabrous or nearly so; hairs on lower surface of base of costae none or very short.
88'Lower surface of rachis and costae hairy throughout.
89Reduced pinnae all very small.
89'Reduced pinnae: upper ones 1.5-2 cm long, lower gradually smaller.
90Largest pinnae c. 6 cm long
90'Largest pinnae at least 10 cm long.
91Fertile pinnae to 16x2 cm, lobed at most 5/8
91'Fertile pinnae to 26 x 3 cm, lobed ¾
92Pinnae lobed to a depth of 2 mm
92'Pinnae lobed at least 1 way to costa
93Pinnae crenate.
93'Pinnae distinctly lobed.
94Pinnae not more than 4.5 x 1.4 cm; veins 4-5 pairs, 1-12 pairs anastomosing.
94'Sterile pinnae to 8 x 1.7 cm; 22 pairs of veins anastomosing; sinus-membrane very short
95Pinnae 5-6 pairs
95'Pinnae 18 pairs
96Fronds dimorphous; sterile pinnae to 25 x 3.5 cm.
96'Fronds not or little dimorphous, pinnae not over 2.5 cm wide.
97Pinnae to 9.5 x 0.8-0.9 cm
97'Pinnae proportionately wider, to at least 1.5 cm wide.
98Lowest normal pinnae much narrowed at base
98'Lowest normal pinnae not narrowed at base.
99Hairs 1 mm long on lower surface of rachis and costae; indusia with long hairs.
99'Hairs in most cases less than 0.5 mm long on lower surface of rachis and costae; glands present on indusia.
100Pinnae lobed less than ½ way to costa
100'Pinnae lobed more than ½ way to costa.
101Reduced pinnae c. 5 pairs
101'Reduced pinnae many pairs
102Lowest veins sometimes both touching sides of sinus-membrane; pinnae lobed ⅔-¾
102'Lowest veins always anastomosing; pinnae lobed c. 3/5.
103Pinnae rigid, lobes of larger ones toothed distally; reduced pinnae not over 8 pairs.
103'Pinnae thin, lobes not toothed; reduced pinnae 12-15 pairs.
104Reduced pinnae 4-5 pairs; upper surface of pinnae bearing appressed hairs between veins
104'Reduced pinnae 8 pairs; upper surface of pinnae lacking appressed hairs
105Hairs on lower surface of costae not appressed.
105'Lower surface of costae covered with closely appressed hairs
106Hairs on lower surface of costae all very short.
106'Some hairs 0.5 mm or more long on lower surface of costae
107Glands present on lower surface of costules and veins.
107'Glands lacking on lower surface of costules and veins.
108Pinnae 3-4 pairs, to 1.1 x 0.5 cm, basal pinnae somewhat reduced.
108'Pinnae more numerous or larger, or several pairs reduced basal pinnae.
109All pinnae with narrowly cuneate basiscopic base
109'Pinnae symmetrically broadly cuneate or truncate at base.
110Few to many pairs of lower pinnae gradually reduced.
110'Transition to reduced basal pinnae (if any) abrupt or nearly so.
111Pinnae subentire to crenate.
111'Pinnae lobed 5-5 towards costa.
112Pinnae to 3.5 x 1.0 cm; pinna-lobes with strongly reflexed edges.
112'Pinnae larger, edges of lobes not strongly reflexed.
113Sporangia setiferous; 12-14 pairs of lower pinnae gradually reduced.
113'Sporangia not setiferous; 4-5 pairs of lower pinnae gradually reduced.
114Sori exindusiate; lower surface of costae and costules glabrous
114'Sori indusiate; short hairs abundant on lower surface of rachis and costae
1151-4 pairs of basal pinnae gradually reduced
115'Many pairs of basal reduced pinnae.
1167-12 pairs of lower pinnae gradually reduced with subabrupt change to 12 pairs much smaller
116'Similar transition but 2-6 pairs of small basal pinnae
117Reduced pinnae 0-3 pairs.
117'Reduced pinnae at least 4 pairs.
118Pinna-lobes strongly concave beneath
118'Pinnae-lobes not concave beneath.
119Pinnae widened distally
119'Pinnae not widened distally.
120Caudex short-creeping; pinnae lobed c. 5 towards costa.
120'Caudex slender, erect; pinnae crenate
121Fronds not dimorphous; sori supramedial.
121'Fronds dimorphous; sori medial
122Pinnae 3.5 x 1.4 cm, narrowed evenly to apex
122'Pinnae larger, abruptly short-acuminate
123Aerophores elongate.
123'Aerophores not elongate.
124Pinnae crenate.
124'Pinnae lobed at least 2/5 towards costa.
125Hairs on lower surface of costae minute
125'Hairs on lower surface of costae appressed
126Hairs on lower surface of costules appressed
126'Hairs on lower surface of costules not appressed.
127Reduced pinnae 20-30 pairs; normal pinnae lobed less than 2 way to costa.
127'Reduced pinnae not more than 12 pairs; normal pinnae lobed 1/2 way to costa or more deeply.
128Reduced pinnae acuminate
128'Reduced pinnae with rounded tips.
129Pinnae lobed 4 to costa.
129'Pinnae lobed about 2 to costa.
130Basal veins anastomosing; upper reduced pinnae 12 mm long.
130'Basal veins free; upper reduced pinnae 3 mm long.
131Pinnae c. 6.5 x 1.3 cm, lowest narrowed at base; indusia glabrous
131'Pinnae c. 11x2 cm, lowest not narrowed at base; indusia bearing long hairs
132Sori elongate
132'Sori not or little elongate.
133Reduced pinnae c. 30 pairs, deflexed, overlapping.
133'Reduced pinnae not over 12 pairs, not overlapping.
134Reduced pinnae acuminate; normal pinnae 20 cm long
134'Reduced pinnae with rounded tips; normal pinnae smaller.
135Sori supramedial.
135'Sori not supramedial.
136Pinnae lobed ¾, sporangia setiferous
136'Pinnae lobed less than ½; sporangia glandular
137Pinnae lobed more than ½
137'Pinnae crenate or lobed less than 1/2.
138Sori indusiate; sporangia with glands.
138'Sori exindusiate; sporangia setiferous
139Pinnae not over 1 cm wide; indusia very small or lacking.
139'Pinnae more than 1 cm wide; indusia all distinct.
140Some hairs on lower surface of rachis and costae 1 mm or more long.
140'Hairs on lower surface of rachis and costae all very short.
141Pinnae commonly more than 2 cm wide, crenate to a depth of 1 mm.
141'Pinnae to 1.7 cm wide, distinctly lobed
142Apex of frond pinna-like, crenate to base
142'Apex of frond deeply lobed at base
143Largest reduced pinnae 2 mm long
143'Largest reduced pinnae at least 7 mm long.
144Sporangia not setiferous.
144'Sporangia setiferous
145Pinnae opposite; caudex 40 cm tall
145'Pinnae not opposite; caudex suberect
146Reduced pinnae c. 30 pairs.
146'Reduced pinnae much fewer.
147Reduced pinnae acuminate
147'Reduced pinnae with rounded tips
148Sporangia bearing glands (sometimes a seta also).
148'Sporangia lacking glands, in most cases bearing setae.
149Hairs on lower surface of costules appressed.
149'Hairs on lower surface of costules not appressed.
150Aerophores elongate.
150'Aerophores not elongate.
151Several pairs of lower pinnae gradually reduced
151'Transition to reduced pinnae ± abrupt.
152Upper reduced pinnae 12 mm, lowest 6 mm long
152'All reduced pinnae very short.
153Pinnae lobed less than 1/2
153'Pinnae lobed more than 1/2.
154Indusia large, firm
154'Indusia small, thin.
155Basal veins anastomosing, second acroscopic vein to sinus-membrane
155'Basal veins often connivent at sinus-membrane, next veins both to margin
156Basal acroscopic vein ending beside sinus-membrane, basiscopic vein at margin above base of sinus.
156'Basal veins both touching sinus-membrane or uniting below it.
157Pinnae 15-20 pairs; reduced pinnae 4-7 pairs
157'Pinnae to 30 pairs; reduced pinnae 2-3 pairs
158Gradual transition to reduced pinnae at base of frond.
158'Abrupt transition to very small reduced pinnae
159Indusia present
159'Indusia absent
160Basal veins not connivent below sinus.
160'Basal veins connivent below sinus or uniting to form an excurrent vein.
161Pinnae deeply lobed.
161'Pinnae almost entire
162Pinnae to 3.6 x 1.0 cm; veins 3-4 pairs
162'Pinnae to 10 x 1.5 cm; veins 9-10 pairs
163Pinnae to 4.2 x 1.1 cm; sori elongate with small indusia
163'Pinnae in most cases much larger; sori otherwise.
164Ten or more pairs of basal pinnae gradually reduced.
164'Abrupt transition to reduced pinnae if present.
165Pinna-margins sinuous or slightly crenate
165'Pinnae deeply lobed
166Reduced pinnae 0-4 pairs on mature plants.
166'Reduced pinnae at least 6 pairs on mature plants.
167Pinnae almost entire, 3.5 cm or more wide
167'Pinnae distinctly lobed, narrower.
168Pinnae lobed more than 1/2
168'Pinnae lobed less than 1/2
169Sori supramedial.
169'Sori medial or inframedial.
170Caudex a long-creeping rhizome
170'Caudex short, erect
171Pinnae crenate
171'Pinnae lobed at least 2/5.
172Pinnae lobed more than 1/2
172'Pinnae lobed less than 1/2
173Aerophores elongate.
173'Aerophores not elongate.
174Pinnae entire or slightly crenate; veins 18-20 pairs
174'Pinnae distinctly lobed; veins rarely more than 12 pairs.
175Pinnae lobed less than ½.
175'Pinnae lobed more than ½.
176Hairs on lower surface of costae and costules appressed.
176'Hairs on lower surface of costae and costules not appressed.
177Lower 12-15 pairs of pinnae gradually reduced, lowest 1 cm long
177'Transition to small pinnae at base of frond abrupt
178Reduced pinnae more than 12 pairs; sporangia not setiferous.
178'Reduced pinnae to 5 pairs; sporangia setiferous
179Sporangia always with several setae.
179'Sporangia rarely with a seta.
180Basal 2-3 pairs of pinnae somewhat narrowed at their bases.
180'All pinnae in lower half of frond narrowed at their bases, lowest much narrowed
181Pinnae to 11 x 2.1 cm, lobed 3/5-2/3; hairs on lower surface of costules antrorse
181'Pinnae to 17 x 2.8 cm, lobed more than 3/4; hairs on lower surface of costules erect
182Pinnae lobed 3/4 or more deeply; reduced pinnae all very small.
182'Pinnae lobed at most 2/3; reduced pinnae 1-1.5 cm long
183Lower surface of rachis glabrous
183'Lower surface of rachis densely covered with erect brown hairs.
184Sporangia not setiferous.
184'Sporangia setiferous.
185Pinnae not or little more than 5 cm long.
185'Pinnae more than 10 cm long.
186Pinnae crenate; sori inframedial.
186'Pinnae lobed more than 1/2; sori supramedial
187Pinnae 10-20 pairs; 2-3 pairs of lower ones gradually reduced.
187'Pinnae to 30 pairs; abrupt change to reduced ones at base.
188Caudex slender, erect; pinnae slightly crenate distally.
188'Caudex very short; pinnae crenate throughout
189No reduced pinnae; normal pinnae distinctly stalked
189'At least 5 pairs lower pinnae gradually or abruptly reduced; all pinnae sessile.
190Sori elongate and indusiate.
190'Sori not elongate, or if so exindusiate.
191Normal pinnae not or little more than 2 cm wide; upper reduced pinnae 4 mm long
191'Normal pinnae commonly 2.5-3.5 cm wide; reduced pinnae much larger
192Abrupt transition to 6 pairs of very small basal pinnae
192'Basal pinnae not very small.
193Rachis quite glabrous on lower surface; pinnae almost entire.
193'Rachis hairy on lower surface; pinnae crenate or lobed throughout
194Caudex terrestrial and long-creeping, or scandent.
194'Caudex various, not long-creeping nor scandent.
195Caudex terrestrial; indusia distinct
195'Caudex scandent; indusia very small or lacking.
196Several pairs of lower pinnae gradually smaller and auricled on acroscopic base
196'Transition to basal reduced pinnae abrupt.
197Lower 1-5 pairs of pinnae gradually reduced.
197'At least 3 pairs of reduced pinnae distinct from normal ones.
198Pinnae to 2 cm long; no indusia
198'Pinnae to at least 4 cm long; indusia present
199Pinnae lobed 1/2 way to costa or more deeply.
199'Pinnae lobed less than 1/2 way to costa.
200Reduced pinnae 20 pairs, all very small
200'Reduced pinnae to 12 pairs, all conspicuous.
201Caudex short, erect; pinnae lobed 1/2
201'Caudex tall, slender, if free-standing; pinnae lobed 2/3-3/4
202Pinnae to 3.5 cm long, slightly crenate
202'Pinnae in most cases larger, deeply crenate or lobed.
203Stipe 40-50 cm long; reduced pinnae 3 pairs, small.
203'Stipe much shorter; reduced pinnae more numerous, conspicuous.
204Pinnae crenate; no long hairs on lower surface of rachis and costae.
204'Pinnae distinctly lobed; long hairs usually present on lower surface of rachis and costae.
205Caudex erect; largest fertile pinnae 17 x 2.5 cm
205'Caudex short-creeping; largest pinnae 8 x 2 cm
206Stipe-scales 1 mm long; pinnae to 4 x 1 cm
206'Stipe-scales 7 mm long; pinnae to 12 x 2 cm