Biodiversity Data Journal :
Taxonomic paper
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Corresponding author:
Academic editor: Daniele Cicuzza
Received: 10 Apr 2015 | Accepted: 10 Jul 2015 | Published: 15 Jul 2015
© 2015 Komla Abotsi, Aboudou Radji, Germinal Rouhan, Jean-Yves Dubuisson, Kouami Kokou
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Abotsi K, Radji A, Rouhan G, Dubuisson J, Kokou K (2015) The Pteridaceae family diversity in Togo. Biodiversity Data Journal 3: e5078. https://doi.org/10.3897/BDJ.3.e5078
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The Pteridaceae family is the largest fern family in Togo by its specific and generic diversity. Like all other families of ferns in the country, Pteridaceae are poorly studied and has no identification key. The objective of this study is to perform a taxonomic revision and list establishment of this family of leptosporangiate ferns in the light of current available knowledge about the family. Pteridaceae was also assessed in terms of its diversity and conservation status, this was conducted through the recent field data and the existing herbaria specimens. The current study permits to confirm the presence of Pteris similis Kuhn. which brought the number of Pteridaceae to 17 in Togo.
This study provides first local scientific information about the fern flora of Togo. It confirmed the presence of Pteris similis Kuhn. in Togo and brought the Pteridaceae family diversity to 17 species. A species identification key is provided for the easy identification of the Pteridaceae of Togo.
Pteridaceae, diversity, revision, identification key, Togo
Ferns have been studied, in the past century, mainly using morphological traits whereas more light have been brought to the group with the recent development of cytology and molecular phylogeny (
As a large family of leptosporangiate ferns (about 10% of the Monilophytes), Pteridaceae undergone several taxonomic and nomenclatural updates (
The Pteridaceae occupies aquatic and terrestrial environments. They are usually terrestrial, but sometimes aquatic, epilithic and epiphytic. However they abound in the humid tropics, the family includes several cosmopolitan species. They have a long or short rhizome, creeping, ascending, sub-erected or erected, and have splinters (more rarely hairs). They have a monomorphic limb, hemi- or rarely dimorphic, simple, pinnate, pedaled, sometimes decurrent; free and simple veins, or sometimes anastomosed, forming a network. The Sporangia are grouped in marginal or intra-marginal sori, without true indusium, often protected by the reflected margin of the lamina, or arranged along the vein. Each sporangia has a vertical and interrupted annulus, with a little or no visible receptacle.
The family is well present in Togo but few studies hitherto focused on it. The current data of the country's biodiversity (
Recent revisions of the family are not taken into account neither at the herbarium of the University of Lomé nor in the flora of Togo. Many names have then been placed in synonymy in recent databases (
The current study aims at updating the Pteridaceae list and taxonomy in Togo. An identification key was created to facilitate the identification of the identified species.
The study area is Togo. It is located in the Gulf of Guinea, and surface covers approximately 56 785 km2. Its forest surface is counts among the least in the West African sub-region.
Three main types of climate are found in Togo. In the North, there is the tropical climate with variations increasingly wet, going to the South. The southern coastal area has a sub-equatorial climate. A transitional climate between these two types is found in the mountains of the south. Togo has varied soils. There are five main soil classes (
Togo ecological zones.
Ecological Zone 1: Refers to the Northern Plains. It enjoys a Sudanese climate characterized by an average of 6 to 7 months of drought. Rainfall varies from 800 to 1000 mm and water per year. The temperatures are between 17 and 39° C. The predominant vegetation is the Sudan savanna with few islands of dry forests and gallery forests. The soil is tropical ferruginous, sandy.Ecological Zone 2: It is covered with a mosaic of dry forests of mountain and forest galleries. The climate is Sudano-Guinean. The rainy season extends from April to October and the dry season is characterized by the presence of the Harmattan, a dry and cold wind. Rainfall is irregular and reaches 1200-1300 mm of water per year. The soils are thin and contain a high proportion of coarse elements. Ferruginous tropical soils are also present.Ecological Zone 3: It corresponds to the Guinean savannas of central area plains enjoying a tropical climate with a rainy season extends from May to October. Rainfall varies between 1200 and 1500 mm per year. The temperature is between 25 and 40° C. The soils are mainly ferruginous. Semi-deciduous forests are found in the southern part and dry forests in the northern part.Ecological Zone 4: This corresponds to the southern part of the Mount "Togo" and has a sub-equatorial climate of transition, characterized by a long rainy season from March to October with a small interruption in August or September. Rainfall varies between 1300 and 1600 mm per year. The vegetation is constitute of rainforests, on deep red lateritic soils.Ecological Zone 5: It is the South of the coastal plains area, with a sub-equatorial climate, characterized by a lack of rainfall in it's southern part. Rainfall varies from 800 mm at the coast up to 1200 mm per year at the northern limit of the zone. The vegetation is composed by a mosaic of savannah, farmland and dry forests (
There have been new harvest in the ecologic zone 4 of Togo in order to enrich the plant materials available for this study.
The study is based on new harvests from the ecological zone 4 (215 specimens) and specimens from herbaria of the University of Lomé (TOGO) (87 specimens) and the National Museum of Natural History in Paris (P) (122 specimens).
New harvests were conducted along the banks of the natural ecosystem's streams in the study area along a topographic gradient. As many others authors,
Data from this new inventory is coupled with ecological and geographical data from previously performed harvests between 1973 and 1994 across the country and available in the RIHA data base (African Herbaria Computer Network) of the herbarium of Lomé.
Each harvest consists of one or more photos of the whole plant in its habitat, a herbarium specimen represented by the whole plant (or a fragment then comprising parts of all organs) and a piece of lamina in silica gel (
The morphological observations of all available specimens (new specimens and old herbarium collections) enabled the establishment of a list of morphological descriptors which have been added to the ecological characteristics of each species (Table
List of descriptors with their discriminating power.
The index value is the ratio between the number of couples with no common values and the total number of couples. For example, the value of the descriptor "habitat" index is 0.12 corresponding to 16 couples with no common values and a total number of 136 available couples.
Descriptors |
XPER |
1. type of habitat |
16/136 (0.12) |
2. type of terrestrial habitat |
21/120 (0.18) |
3. biotope |
30/136 (0.22) |
4. fronds dimorphism |
52/136 (0.38) |
5. type of dimorphism |
0/6 (0.0) |
6. frond length |
39/136 (0.29) |
7. frond width |
85/136 (0.63) |
8. fronds insertion on the rhizome |
60/136 (0.44) |
9. limb general shape |
102/136 (0.75) |
10. limb length |
56/136 (0.41) |
11. limb width |
82/136 (0.6) |
12. limb length/width ratio |
83/136 (0.61) |
13. limb texture |
72/136 (0.53) |
14. number of limb divisions |
90/136 (0.66) |
15. pinnae length |
38/105 (0.36) |
16. pinnae width |
29/105 (0.28) |
17. pinnae length/width ratio |
44/105 (0.42) |
18. pinnae dimorphism |
36/105 (0.34) |
19. position of the dimorphism |
28/66 (0.42) |
20. basal pinnae basiscopical development |
0/10 (0.0) |
21. terminal pinnae shape |
7/28 (0.25) |
22. pinnae general shape |
38/105 (0.36) |
23. pinnae base shape |
76/105 (0.72) |
24. pinnule general shape |
24/45 (0.53) |
25. pinnae insertion on the rachis |
54/105 (0.51) |
26. pinnae stipe length |
16/28 (0.57) |
27. winged frond |
56/105 (0.53) |
28. frond 3-branched |
10/21 (0.48) |
29. type of veins organization |
96/136 (0.71) |
30. type of dichotomy |
5/15 (0.33) |
31. veins organization |
4/15 (0.27) |
32. limb margin |
83/136 (0.61) |
33. stipe color |
84/136 (0.62) |
34. stipe length |
55/136 (0.4) |
35. rhizome size |
42/136 (0.31) |
36. rhizome habit |
36/136 (0.26) |
37. roots insertion on the rhizome |
0/136 (0.0) |
38. frond type |
0/136 (0.0) |
39. sporangia organization |
30/136 (0.22) |
40. sori position |
14/105 (0.13) |
41. sori position in relation to veins |
0/0 (0.0) |
42. sori position in relation to lamina |
33/91 (0.36) |
43. sori shape |
54/105 (0.51) |
44. indusium |
86/136 (0.63) |
45. indusium opening |
0/1 (0.0) |
46. indusium shape |
0/1 (0.0) |
47. indusium texture |
0/1 (0.0) |
48. covering |
30/136 (0.22) |
49. position of covering |
6/105 (0.06) |
50. rhizome covering |
0/91 (0.0) |
51. rhizome scale’s shape |
48/91 (0.53) |
52. rhizome scale’s color |
32/91 (0.35) |
53. stipe covering |
15/36 (0.42) |
54. stipe scale density |
12/21 (0.57) |
55. stipe muricule size |
0/0 (0.0) |
56. stipe hairs density |
0/0 (0.0) |
57. length of stipe hairs |
0/0 (0.0) |
58. limb covering |
0/6 (0.0) |
59. type of covering |
6/6 (1.0) |
60. limb muricule size |
0/0 (0.0) |
61. farinose coat color |
0/0 (0.0) |
62. limb hairs density |
0/0 (0.0) |
Xper² is a free software for management, editing, and analysis of taxonomic knowledge bases (
All species identified as a result of the study and the identification of all available specimens were then associated with the states of the descriptors that characterize them. This same approach was also used by
The different states of retained descriptors were used to create a dichotomous identification key of the Togolese Pteridaceae family species. For this purpose, the specimens were segregated into two groups according to their similarities and dissimilarities. Within each group, two groups are newly created and so on until the species rank. The key nodes are defined by the dissimilarities while the branches are defined by the similarities between species.
Geographic data were collected from herbarium specimen labels and new harvests sheets in order to edit a distribution map of the Pteridaceae family in Togo.
Acrostichum inaequale Willd, A. guineense Gaudich, Chrysodium inaequale (Willd.) Fée, C. vulgare Fée, C. aureum (L) Mett
Native
Togo (Ecological Zone 5), USA, U.S. Virgin Isl., Costa Rica, Galapagos, Puerto Rico, Hispaniola, Jamaica, Cuba, Nicaragua, Barbados, Mexico, Belize, Guatemala, Honduras, Panama, Colombia, Venezuela, Ecuador, Peru, Brazil, Trinidad, Guadeloupe, Martinique, St. Lucia, Grenada, Barbados, Guyana, Surinam, French Guiana, Cayman Isl., Bahamas, Turks & Caicos Isl., Isla del Coco, Australia, South Africa, Zambia, Mozambique, SE-Zimbabwe, Kenya, Tanzania, Zanzibar, Pemba Isl., Principe Isl., Sao Tomé, Bioko Isl., Senegal, Guinea-Bissau, Guinea, Gambia, Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, Equatorial Guinea, Gabon, Angola, Madagascar, Mauritius, La Réunion, Micronesia, Palau Isl., Fiji, Western Samoa, American Samoa, Marianas, Society Isl., Tonga, New Caledonia, Niue, Austral Isl., China, Taiwan, Ryukyu Isl., peninsular Malaysia, India, Andaman Isl., Nicobar Isl., Philippines, Sri Lanka, Vietnam, Thailand, Cambodia, Sulawesi
Acrostichum aureum is a fern with erect rhizome and fronds in clumps. Young fronds are entire while adults are pinnate, measuring 1 to over 2m in length. The petiole is 30-50 cm long, rigid and naked. The leaf blade is oblong-lanceolate, about 50 cm to 2 m long, with lanceolate pinnae. The pinnae are 20-30 cm long for 3-5 cm wide, alternate, spaced about 3 cm, with cuneate-oblique base. The upper pinnae are sessile while basal pinnae are stalked (Fig.
Acrostichum dichotomum Forssk., A. radiatum (Sw.) Poir, Acropteris radiata (Sw.) Link, Pteris radiata (Sw.) Bojer, Asplenium polydactylon Webb., A. radiatum Sw, Actiniopteris australis Sim., A. australis var. radiata (Sw.) C. Chr
Togo (Ecological Zone 2), South Africa, Namibia, Swaziland, Botswana, Zimbabwe, Mozambique, Zambia, D.R.Congo, Zimbabwe, Uganda, Kenya, Tanzania, Zanzibar, Djibouti, Mali, Nigeria, Cameroon, Somalia, Madagascar, Comores, Seychelles, La Réunion, Mauritius, Angola, Sudan, SE-Egypt, Ethiopia, N-Yemen, Saudi Arabia, India, Sri Lanka, Iran, Afghanistan, Pakistan, Nepal, Burma, Cape Verde Isl.
Small fern with an erect rhizome and fronds in clumps, with lanceolate scales toothed at their base, Actiniopteris radiata has a petiole of 5-15 cm long, sparsely scaly (Fig.
Adiantum capillus-gorgonis Webb, A. caudatum sensu Hook, A. caudatum var. hirsutum Kuhn, A. zollingeri sensu Carruth.
Togo (Ecological Zone 4), South Africa, Swaziland, Namibia, Zimbabwe, Zambia, Malawi, Mozambique, Ghana, Nigeria, Uganda, Kenya, Tanzania, Somalia, Madagascar, Ivory Coast, Angola, Ethiopia, N-Yemen, S-Yemen, Oman, Saudi Arabia, Pakistan, Galapagos, Jammu & Kashmir, India, Cape Verde Isl.
Adiantum incisum has a short and erect rhizome (Fig.
Adiantum philippense L., A. lunulata Burm., A. lunatum Cav., A. arcuatum Sw.
Togo (Ecological Zones 3 and 4), China, Taiwan, Australia, Jammu & Kashmir, India, Andaman Isl., Myanmar, Philippines, Thailand, Laos, Cambodia, Vietnam, peninsular Malaysia, Sulawesi, Sri Lanka, Nepal, Moluccas, Oman, S-Yemen, Zimbabwe, Mozambique, South Africa, Zambia, Malawi, Chad, Tanzania, Sao Tomé, Bioko Isl., Senegal, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Benin, Niger, Nigeria, Cameroon, Central African Republic, Sao Tome, Congo, D.R.Congo, Angola, Ethiopia, Sudan, Madagascar, Comores, Burkina Faso, Mali, Sudan, Southern Marianas, Fiji, Micronesia, Palau Isl., Western Samoa, Cuba, Cape Verde Isl.
Adiantum lunulatum has a short rhizome, slightly erect or creeping, wearing dark brown scales of about 3 mm long. The fronds are arched and arranged in tufts (Fig.
Adiantum chevalieri Christ.
Adiantum schweinfurthii is a fern with a short rhizome, with brown scales, linear-lanceolate, long-acuminate, entire. The fronds are in clumps, pinnate, oblong-lanceolate, 12-34 cm long (Fig.
Adiantum prionophyllum var. γ Hook., A. tetraphyllum sensu Hook & Bak., A. tetraphyllum var. obtusum Kuhn., A. tetraphyllum var. vogelii (Keyserl.) Bonap.
Togo (Ecological Zones 4 and 5), Uganda, Zanzibar, Principe Isl., Bioko Isl., Senegal, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Benin, Nigeria, Cameroon, Central African Republic, Equatorial Guinea, Gabon, Congo, D.R.Congo, Angola
Adiantum vogelii is a fairly large fern with developed creeping rhizome, up to 70 cm long, bearing piliform black scales of 2 to 3 mm long (Fig.
Acrostichum siliquosum L., Pteris thalictroides (L.) Sw., P. siliquosum (L.) P. Beauv., P. cornuta P. Beauv., Ceratopteris gaudichaudii Brongn., C. cornuta (P. Beauv.) Lepr, C. siliquosa (L.) Copel, C. thalictroides var. thalictroides, C. thalictroides var. cornuta (P. Beauv.) Schelpe
Ceratopteris thalictroides is an annual aquatic fern, with dimorphic pale-green fronds, irregularly pinnate. Sterile fronds are wider than the fertile fronds. They have a thin texture and are traversed by anastomosing veins. The sterile fronds have a stem of 8 to 25 cm long, ovate to deltoid lamina, 20 to 40 cm long and 7-30 cm wide, pinnate, pinnatifid or 2-3-pinnatifid, with winding lobes. The terminal segments are triangular to lanceolate, hairless. The fertile fronds have a stem of more than 40 cm long, a limb of 24-50 cm long and 12-30 cm wide, 2-4-pinnate, with linear ultimate segments of more than 4 cm long for 1-2 mm wide, glabrous. The sporangia are located along the veins. They are protected by a marginal entire pseudo-indusium, membranous, formed by the reflected margin of the lamina, with 30-70 thickened cells (Fig.
Doryopteris nicklesii Tardieu., Pellaea geraniifolia (Raddi) Fée
Doryopteris concolor var. nicklesii is a terrestrial fern, with closely spaced fronds, deltoids, measuring 10-35 cm long and 5-15 cm wide. The lamina is bipinnatifid. Pinnae measure 2-6 cm long and 0.7 to 3 cm wide. The petiole is covered by scattered scales. The sori, linear, protected by false indusia, are continuous at the edges of the leaf blade except at the bottom of sinus. Doryopteris concolor var. nicklesii usually grows on the banks of rivers in rainforest.
Doryopteris concolor var kirkii (Hook.) Wiss., D. concolor (Langsd. & Fisch.) Kuhn, Cheilanthes kirkii Hook, C. argentea sensu Peter F.D., Pellaea geraniifolia sensu Oliv, Adiantum palmatum Schumach. Beskr.
Togo (Ecological Zone 4), South Africa, Namibia, Swaziland, Botswana, Zambia, Zimbabwe, Malawi, Mozambique, Angola, Cameroon, Central African Republic, Liberia, Tanzania, Uganda, Madagascar, Comores, Guinea, Ivory Coast, Ghana, Nigeria, Socotra, Ethiopia, S-India, Sri Lanka, Philippines, Vietnam, Sulawesi, Fiji, Society Isl., Tonga, New Caledonia, Western Samoa, American Samoa, Marquesas Isl., Austral Isl., Australia, Taiwan, China
Doryopteris kirkii has a short rhizome, closely spaced fronds, wearing very thickened scales in the center and very thin at the edges (Fig.
Vittaria guineensis Desv, V. congoensis H.Christ, V. guineensis var. cancellata Hieron. Pteris guineensis (Desv) Desv
Haplopteris guineensis var. guineensis is a small epiphytic fern, with a shortly creeping rhizome covered by scales, black and lanceolate, darker in the center, with a colorless light. The frond is linear-lanceolate, 10 to 60 cm long and 0.4 to 1.2 cm width. The stipe is 2-5 cm long, blackish at the base. The end of the leaf blade is acute, mucronnate, with terminal hydathode. Midrib only appears only at the base of the frond. The lateral ribs are not visible, except for the young fronds. The sori are marginal, immersed. The plant usually grows on the trunks of trees in the gallery forests and rainforests.
Pellaea doniana Hook, Pteris doniana (Hook.) Kuhn, Pteridella doniana (Hook.) Kuhn.
Togo (Ecological Zones 3 and 4), Burundi, Ghana, Malawi, Tanzania, Uganda, Zambia, Kenya, Mozambique, Seychelles, Principe Isl., Sao Tomé, Chad, Senegal, Guinea, Sierra Leone, Liberia, Ivory Coast, Benin, Bioko Isl., Nigeria, Cameroon, Central African Republic, Annobon Isl., Congo, D.R.Congo, Angola, Mali, Sudan
Pellaea dura is a fern with erect rhizome, with fronds in clumps, from 19 to 60 (-100) cm long, with narrow scales, pale and colorless to light (Fig.
Acrostichum calomelanos. L., A. ebeneum L, Gymnogramma calomelanos (Link) Kaulf., G. distans Link., Ceropteris calomelanos (L) Underw., Pityrogramma chamaesorus Domin., P. insularis Domin.
Togo (Ecological Zones 2 and 4), Bahamas, Mexico, Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Venezuela, Ecuador, Peru, Bolivia, Brazil, Paraguay, Uruguay, St. Martin, St. Barthelemy, Antigua, Saba, St. Eustatius, St. Kitts, Montserrat, Guadeloupe, Marie Galante, Dominica, Martinique, St. Lucia, St. Vincent, Grenada, Barbados, Guyana, Surinam, French Guiana, Puerto Rico, Cuba, Jamaica, Hispaniola, Vieques Isl., Virgin Isl., Curacao, Isla del Coco, Australia (I), Taiwan (I), Ryukyu Isl. (I), China (I), Mozambique (I), Gabon (I), Uganda (I), Tanzania (I), Bioko Isl. (I), Sao Tomé and Principe (I), Senegal (I), Guinea (I), Sierra Leone (I), Liberia (I), Ivory Coast (I), Ghana (I), Nigeria (I), Cameroon (I), Gabon (I), Congo (I), Angola (I), D.R.Congo, Zambia (I), Madagascar (I), Mauritius (I), La Réunion (I), Comores (I), Seychelles (I), Burkina Faso (I), Marquesas Isl. (I), Society Isl. (I), Southern Marianas (I), Fiji (I), Palau Isl. (I), Micronesia (I), Hawaii (I), Malaysia (I), Borneo (I), Thailand (I), India (I), Sri Lanka (I), Andaman Isl. (I), Nicobar Isl. (I), Cambodia (I), Vietnam (I), Laos (I), Philippines (I), Sulawesi (I), Moluccas (I), USA (I)
Pityrogramma calomelanos var. calomelanos has a short rhizome, of about 8 mm diameter, wearing linear scales of more than 4 mm long, entire, brown clear. The fronds are arranged in tufts, erect to arching (Fig.
Pteris spinulifera Schum.
Togo (Ecological Zone 4), Gabon, Comores, Uganda, Kenya, Tanzania, Pemba Isl., Principe Isl., Sao Tomé, Bioko Isl., Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Benin, Nigeria, Cameroon, Central African Republic, Equatorial Guinea, Congo, D.R.Congo, Angola, Burundi, Sudan, Seychelles
The rhizome of Pteris atrovirens is short and covered by dark lanceolate scales of about 4 mm long, with pale margins. The fronds are organized in tufts, from 0.25 to 1 m long. The petiole is 20 to 50 cm long, straw-colored, reddish or purple at the base. The leaf blade is elliptic-lanceolate, 20-50 cm long and 15-60 cm wide, bipinnatifid, composed of 5 to 7 pairs of lateral pinnae. Upper pinnae are opposed. The middle ones are alternate, short-stalked or subsessile, cuneate at the base, divided into about 15 rounded segments, oblong, toothed at the top, separated by narrow sinus (Fig.
Pteris johnstonii Bak, P. aethiopica Christ, P. atrovirens var. cervonii Bonap, P. burtonii var. aethiopica (Christ) Tardieu.
Togo (Ecological Zones 2, 4 and 5), Guinea, Sierra Leone, Tanzania, Principe Isl., Bioko Isl., Ivory Coast, Liberia, Ghana, Nigeria, Cameroon, Central African Republic, Gabon, Congo, D.R.Congo, Angola, Burundi
The rhizome of Pteris burtonii is short, erect, covered with black scales, with pale margins, lanceolate to linear-lanceolate (3 to 4 mm long). The fronds are tufted, 0.3 to 1m long (Fig.
Pteris congoensis Christ., P. spinulifera sensu Tardieu.
Togo (Ecological Zone 4), Uganda, Tanzania, Principe Isl., Sao Tomé, Bioko Isl., Guinea, Mali, Sierra Leone, Liberia, Ivory Coast, Ghana, Benin, Nigeria, Cameroon, Central African Republic, Gabon, Congo, D.R.Congo, Angola, Sudan
Pteris similis is a terrestrial fern, with an erect rhizome (up to 15 cm), with fronds in clumps, coverd by black scales, linear or linear-lanceolate. The fronds are solitary or tufted, reaching 1.8 to 4 (-6) m tall, often rooting at the apex (Fig.
Pteris kamerunensis Hieron., P. quadriaurita sensu Sim., P. biaurita sensu Sim.
Togo (Ecological Zones 2, 3, 4 and 5), Principe Isl., Bioko Isl., Senegal, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, Central African Republic, Gabon, Congo, Angola, Sudan, Madagascar, Mali
Pteris togoensis is a terrestrial fern, with erect or shortly creeping rhizome. Fronds are scaly, in clumps, often reaching over 1m long (Fig.
Pteris marginata Bory., Litobrochia tripartita (Sw.) Presl
Togo (Ecological Zone 4), Australia, Taiwan, China, Singapore, Borneo, S-India, Andaman Isl., Nicobar Isl., Sri Lanka, peninsular Malaysia, Philippines, Thailand, Sulawesi, Sumatra, Laos, Nepal, Vietnam, Java, Moluccas, Uganda, Kenya, Tanzania, Zanzibar, Principe Isl., Sao Tomé, Chagos Arch., Galega Isl., Bioko Isl., Guinea, Sierra Leone, Ivory Coast, Ghana, Benin, Liberia, Nigeria, Cameroon, Central African Republic, Equatorial Guinea, Gabon, Congo, Madagascar, La Réunion, Comores, Seychelles, Mauritius, Angola, Marianas, Fiji, Palau Isl., Micronesia, Marshall Isl., Nauru, Gilbert Isl., Tonga, New Caledonia, American Samoa, Western Samoa, Tuvalu, Society Isl., Austral Isl., Niue, Marquesas Isl., Costa Rica (I), Costa Rica (I), Panama (I), Colombia (I), Venezuela (I), Brazil (I), Ecuador (I), Peru (I), St. Lucia (I), Puerto Rico (I), Jamaica (I), Surinam (I), French Guiana (I), Mexico (I), USA (I)
Pteris tripartita is a big fern, terrestrial or epiphytic, with erect, short and thick rhizome, bearing large scales. The fronds are in clumps, 1.5 to 2.5m high (Fig.
Key to the Pteridaceae species of Togo |
||
1 | Aquatic plant, partially or totally submerged | 2 |
– | Terrestrial plant, epiphytic, or lithophyte | 3 |
2 | Mangrove plant, lamina coriaceous, oblong-lanceolate, pinnate, lower pinnae short-stalked and terminal pinnae sessile, acrostichoids sori (sporangia covering completely the lower surface of the lamina) | Acrostichum aureum |
– | Fresh water plant, completely submerged, lamina membranous, lanceolate, fertile frond, 2-4 pinnate, sporangia protected by the reflected margin of lamina | Ceratopteris thalictroides |
3 | Frond entire or flabellate | 4 |
– | Frond pinnate, pinnatifid, multi-pinnate or multi-pinnatifid | 5 |
4 | Plant epilithic, lamina fan-shaped, flabellate, coriaceous, stipe sparsely scaled | Actiniopteris radiata |
– | Epiphytic plant, lamina linear-lanceolate, stipe blackish at the base, marginal sori immersed | Haplopteris guineensis var. guineensis |
5 | Frond pinnate | 6 |
– | Frond multi-pinnate or multi-pinnatifid | 9 |
6 | Pinnae long-stalked | Adiantum lunulatum |
– | Pinnae sessile or sub-sessile | 7 |
7 | Pinnae deeply or slightly incised, generally hairy, becoming smaller at the top of the leaf, blade oblong to deltoid, rachis and stipe dark brown, densely hairy | Adiantum incisum |
– | Pinnae entire or lobed, oblong, oval or lanceolate, glabrous, stipe and rachis black and shiny | 8 |
8 | Sori linear, protected by the reflected margin of lamina, terminal pinnae similar to lateral ones, lamina dark green, with coriaceous texture | Pellaea dura |
– | Sori oblong-kidney shaped, pinnae lobed and serrated feathers on the upper margin, light green leaf blade, papery textured lamina | Adiantum schweinfurthii |
9 | Sori moon crescent shaped, rhomboid-dimidiate pinnae, lamina upper margin incised | Adiantum vogelii |
– | Sori linear, pinnule rhomboidal, non-dimidiate | 10 |
10 | Stipe black | 11 |
– | Stipe not black | 13 |
11 | Limb oblong-lanceolate, not winged, covered by a white powdery layer on the underside | Pityrogramma calomelanos var. calomelanos |
– | Limb deltoid, broadly winged, 3-branched at the base, sori marginal | 12 |
12 | Sori linear, interrupted | Doryopteris kirkii |
– | Sori linear, continuous over the entire margin of the lamina, except at the base of sinus | Doryopteris concolor var. nicklesii |
13 | Limb oval-deltoid light green, 3-pinnate, equal pinnae, lamina herbaceous, stipe tri-branched at the base of the limb | Pteris tripartita |
– | Limb lanceolate to deltoid, oblong, elliptic or oval, basal pinnae developed basiscopically, stipe not branched | 14 |
14 | Sori linear or not reaching the bottom of the base or the apex of the pinnae, stipe reddish at the base | Pteris togoensis |
– | Sori U-shaped, interrupted at the top of pinnae | 15 |
15 | Frond deltoid, more or less lanceolate, brown stipe, simple or pinnatifid pinnae, both types can coexist on the same frond, oblong-lanceolate | Pteris burtonii |
– | Frond not deltoid, stipe straw colored, pinnatifid pinnae only | 16 |
16 | Stipe channeled, muricate, purplish or brownish at the base, pinnae and pinnule oblong-lanceolate, lamina proliferous | Pteris similis |
– | Stipe reddish at the base, pinnae oblong, pinnule oblong-falcate, limb non-proliferous | Pteris atrovirens |
From all the studied specimens, 17 species have been identified, belonging to the Pteridaceae family. They are distributed into 9 genera which are themselves distributed into 4 subfamilies (Fig.
Pteris similis Kuhn was harvested in a riparian forest at Dikpéléou in Adélé region (ASM 0162). This collection confirms the presence of this undocumented species in Togo. The complete list of taxa, their synonyms and their distribution in Togo are indicated in the checklist. The geographic data on the family helped to map species distribution for the whole country (Fig.
The recognition and distinction of taxa within the Pteridaceae species of Togo is based on their habitat, the shape and divisions of their limb, the organization of sporangia in sori, their shape and position. The nature and position of coverings, and exudates are also very decisive. However, the dimensions of the sporophyte are less crucial than the previous characters.
Most of recorded species (14 species of 17 in total) are represented in the ecological zone 4. Some among them are unique to this area (Adiantum incisum, Doryopteris kirkii, Haplopteris guineensis var. guineensis, Pteris atrovirens, Pteris similis and Pteris tripartita). On the other side, Actiniopteris radiata and Acrostichum aureum are respectively exclusive to the ecological zones 2 and 5. The entire chain of the mountains of Togo is rich: 16 species out of 17. This distribution shows the role played by biodiversity refuges such as mountains (
Three families in the RIHA database of the herbarium of Lomé correspond to the current delimitation of the Pteridaceae (
RIHA data |
Current data |
||
Family |
Species name |
Family |
Species name |
Pteridaceae |
Acrostichum aureum L. |
Pteridaceae |
Acrostichum aureum L. |
Adiantaceae |
Actiniopteris radiata (Sw.) Link. |
Pteridaceae |
Actiniopteris radiata (Sw.) Link. |
Adiantaceae |
Adiantum incisum Forssk. |
Pteridaceae |
Adiantum incisum Forssk. |
Adiantaceae |
Adiantum philippense L. |
Pteridaceae |
Adiantum lunulatum Burm. |
Adiantaceae |
Adiantum schweinfurthii Kuhn. |
Pteridaceae |
Adiantum schweinfurthii Kuhn. |
Adiantaceae |
Adiantum vogelii Mett. ex Keyserl. |
Pteridaceae |
Adiantum vogelii Mett.ex Keyserl. |
Adiantaceae |
Ceratopteris cornuta (Beauv) Lepr. |
Pteridaceae |
Ceratopteris thalictroides (L) Brongn. |
Adiantaceae |
Doryopteris concolor var kirkii (Hook.) Alston. |
Pteridaceae |
Doryopteris kirkii (Hook.) Alston. |
Adiantaceae |
Doryopteris concolor var nicklesii (Tard.) Schelpe |
Pteridaceae |
Doryopteris concolor var nicklesii (Tard.) Schelpe |
Adiantaceae |
Pellaea doniana J.Sm. ex Hook. |
Pteridaceae |
Pellaea dura (Willd.) Hook. |
Adiantaceae |
Pellaea doniniana Link |
- |
- |
Adiantaceae |
Pityrogramma calomelanos var. calomelanos |
Pteridaceae |
Pityrogramma calomelanos var. calomelanos |
Adiantaceae |
Nephrolepis bisserata (Sw.) Schott. |
Nephrolepidaceae |
Nephrolepis bisserata (Sw.) Schott. |
Adiantaceae |
Nephrolepis undulata (Afzel. ex Sw.) J.Sm. |
Nephrolepidaceae |
Nephrolepis undulata (Afzel. ex Sw) J.Sm. |
Vittariaceae |
Vittaria guineensis var camerooniana |
Pteridaceae |
Haplopteris guineensis var guineensis |
Pteridaceae |
Pteris atrovirens Wild. |
Pteridaceae |
Pteris atrovirens Wild. |
Pteridaceae |
Pteris burtonii Bak. |
Pteridaceae |
Pteris burtonii Bak. |
Pteridaceae |
Pteris marginata Bory. |
Pteridaceae |
Pteris tripartita Sw. |
Pteridaceae |
Pteris togoensis Hieron. |
Pteridaceae |
Pteris togoensis Hieron. |
- |
- |
Pteridaceae |
Pteris similis Kuhn. |
Togo ecological zone 4 concentrates 94.12 % of the species diversity of Togolese Pteridaceae. Mountain forests of this area seem like refuges for biodiversity (
The expansion of croplands is also a real threat to the Pteridaceae diversity. Indeed, with the expansion of agriculture added to the effect of bushfires at the detriment of the natural ecosystems (
Similarly, the current prerogatives on the carbon stock promote species that store more carbon without necessarily referring to the local flora. Therefore, timber plantations like Tectona grandis, Eucalyptus spp., Gmelina arborea, Nauclea diderrichii and Senna siamea which are mostly exotic are encouraged (
This study clarifies the nomenclature and systematic boundaries of the Pteridaceae in Togo. The Pteridaceae accounts for 20 % of the species diversity and 23.7% of the generic diversity of Monilophytes in Togo. It comprises a variety of 17 species included into 9 genera. Major genera are Pteris L. and Adiantum L. with respectively 5 and 4 species for each. Despite its relatively high diversity (the highest among ferns in Togo), the Pteridaceae are not distributed uniformly over the study area. Approximately 94.12 % of the species are confined in the ecological zone 4 which enjoys a tropical climate and is covered by a semi-deciduous evergreen forest. The zone is like a refuge for biodiversity. Few species are still subservient to the ecological zone 2 (Actiniopteris radiata) or 5 (Acrostichum aureum).
This study is a basis for future valorization of the family. Considerations should be given to ex-situ conservation as well as restoration and conservation of some natural degraded areas to conserve the diversity of ferns and other Pteridaceae in Togo. Further studies extended to the whole West African sub-region would be needed for a better knowledge of the Pteridaceae.