Parmotrema
Creators: name: Masson, Didier
name: Magain, Nicolas
name: Sérusiaux, Emmanuël
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Lecanoromycetes
Lecanorales
Parmeliaceae
Parmotrema

description: Identification key to the Parmotrema species of Réunion Island
1. Medulla P− or P+ faint yellow ......................................................................................................................................................... 2
- Medulla P+ orange ......................................................................................................................................................................... 18
2. Medulla K−, C−, KC− ...................................................................................................................................................................... 3
- At least one of these 3 tests positive ................................................................................................................................................. 5
3. Without vegetative propagules .......................................................................................................................... [P. appendiculatum] (lobe margins and apothecia with corniculate laciniae, apothecial disc imperforate, medulla pigmented yellow near apothecia and containing barbatic acid and secalonic acid A; very rare species not recovered on Réunion since the 19 th century)
- With vegetative propagules .............................................................................................................................................................. 4
4. Thallus sorediate, lobes without cilia ................................................................................................................... P. praesorediosum (upper surface emaculate, soralia linear marginal when young, becoming labriform and crescent-shaped [Fig. 34D], medulla with fatty acids other than protolichesterinic acid; uncommon species on Réunion, at low elevations)
- Thallus isidiate and/or laciniate, cilia numerous ............................................................................................................. P. intonsum (shaggy appearance [Fig. 21E], upper surface ± distinctly punctiform white-maculate, esorediate, medulla with protolichesterinic acid as major substance; rather common in Reunionese cloud forests)
5. Medulla K+ yellow, C−, KC− (atranorin, fatty acids) .......................................................................................... P. praesorediosum (chemotype with atranorin, in addition to fatty acids, in the medulla)
- Other medullary reactions ................................................................................................................................................................ 6
6. Medulla K+ slowly pinkish brick red, C−, KC+ fleeting violet then brick red (lividic acid chemosyndrome) ......... P. reunionicum (lobe margins with conspicuous cilia, upper surface emaculate or faintly punctiform white-maculate, soralia mainly marginal and forming ± rounded clusters with age [Fig. 36C]; rare species, only known from a single locality)
- Medulla K−, C+ and/or KC+ pink, red, orange, or purple (lividic acid chemosyndrome absent) ................................................... 7
7. Medulla C+ and KC+ pink, red or orange ........................................................................................................................................ 8
- Medulla C−, KC+ purple, pinkish or orange .................................................................................................................................. 12
8. Medulla C+ and KC+ orange .............................................................................................................................. P. aurantioreagens (lobe margins ciliate, upper surface faintly to clearly effigurate white-maculate, soralia marginal at the tip of short laciniae [Fig. 7D], medulla with barbatic and 4- O -demethylbarbatic acids as major substances; rare species, only known from a single locality)
- Medulla C+ and KC+ pink or red ..................................................................................................................................................... 9
9. Thallus sorediate ............................................................................................................................................................................. 10
- Thallus isidiate ................................................................................................................................................................................ 11
10. Lobes with marginal cilia ................................................................................................................................................... P. cooperi (upper surface faintly effigurate white-maculate, soralia marginal at first, then submarginal on revolute lobe apices [Fig. 13D], medulla with lecanoric acid; in leeward Acacia montane forests on Réunion)
- Lobes without cilia ................................................................................................................................................... P. austrosinense (upper surface emaculate or faintly effigurate white-maculate, soralia linear and marginal [Fig. 8D], medulla with lecanoric acid; uncommon species on Réunion)
11. Lower surface at main lobe tips with a brown erhizinate marginal zone 1–3 mm wide, lobes 2–9 mm wide, medulla with evernic acid .......................................................................................................................................................................... P. meiospermum (lobe margins eciliate, upper surface faintly to clearly punctiform white-maculate, isidia marginal and laminal, eciliate and coralloid-branched, medulla with evernic and lecanoric acids; rare species)
- Lower surface at main lobe tips with a brown erhizinate marginal zone 4–15 mm wide, lobes 5–20 mm wide, medulla without evernic acid ..................................................................................................................................................................... P. tinctorum (lobe margins eciliate, upper surface emaculate to faintly white-maculate, isidia marginal and laminal, eciliate, simple to coralloid-branched, medulla with lecanoric acid; common species on Réunion, from sea level to the upper limit of cloud forests)
12. Thallus without vegetative propagules ........................................................................................................................................... 13
- Thallus with isidia or soralia .......................................................................................................................................................... 14
13. Pycnidia conspicuous, marginal, verruciform (Fig. 43B); thalline exciple smooth to rugose .................................... [P. thomsonii] (lobe margins ciliate, upper surface distinctly white-maculate, apothecial disc perforate, medulla with alectoronic and α-collatolic acids; very rare species not recovered on Réunion since the 19 th century)
- Pycnidia inconspicuous, immersed; thalline exciple with abundant and well-developed isidioid protuberances (Fig. 26C) ............ .............................................................................................................................................................................................. P. mirum (lobe margins ciliate but cilia sometimes rare, upper surface emaculate, apothecial disc perforate or imperforate, medulla with alectoronic acid (constant) with or without α-collatolic acid; uncommon species on Réunion)
14. Thallus sorediate, without isidia ...................................................................................................................... P. cf. negrosorientale (lobe margins ciliate, upper surface faintly to clearly white-maculate, soralia generally terminal at the tip of laciniae [Fig. 27D], never laminal, medulla with alectoronic and α-collatolic acids as major substances; uncommon species on Réunion)
- Thallus isidiate, with or without soredia ........................................................................................................................................ 15
15. Medulla with norlobaridone .............................................................................................................................................. P. mezierii (lobe margins ciliate, upper surface ± distinctly punctiform white-maculate, isidia coralloid, often ciliate [Fig. 25C & 25D], medulla with norlobaridone and protolichesterinic acid as major substances; uncommon species on Réunion)
- Medulla without norlobaridone ...................................................................................................................................................... 16
16. Apothecia present, usually numerous; thalline exciple with abundant and well-developed isidioid protuberances .......... P. mirum (morphotype with laminal isidia [Fig. 26D])
- Apothecia absent ............................................................................................................................................................................ 17
17. Isidia only present, upper cortex not fragile, medulla without α-collatolic acid ........................................................... P. crossotum (lobe margins conspicuously ciliate, upper surface emaculate or faintly white-maculate, isidia mainly marginal, often ciliate [Fig. 17C & 17D], medulla with alectoronic acid; uncommon species on Réunion, in montane rainforests)
- Isidia and soredia present, upper cortex fragile, medulla with α-collatolic acid .............................................................. P. mellissii (lobe margins conspicuously ciliate, upper surface emaculate or faintly white-maculate, isidia mainly marginal, often ciliate, soon becoming sorediate [Fig. 24D], medulla with alectoronic and α-collatolic acids; rare species on Réunion, in cloud forests)
18. Thallus without vegetative propagules ........................................................................................................................................... 19
- Thallus with vegetative propagules ................................................................................................................................................ 21
19. Medulla K+ yellow then dark red, lower surface often with rhizines to the margins, mean ascospore length <16 µm .................... ........................................................................................................................................................................................... P. cetratum (lobe margins ciliate, upper surface reticulate white-maculate, apothecial disc perforate, medulla with salazinic and consalazinic acids; very rare species on Réunion)
- Medulla K−, lower surface with a broad erhizinate marginal zone, mean ascospore length> 16 µm .......................................... 20
20. Lobes ciliate, medulla UV+ blue-white, KC+ fleeting purple pink, then pink-orange, mean ascospore length> 22 µm .................. .......................................................................................................................................................................................... P. nemorum (upper surface emaculate, rarely faintly white-maculate, medulla white, sometimes tinged with a reddish purple pigment, apothecial disc imperforate, amphithecium and stipe with ± prominent veins and coarse isidioid protuberances [Fig. 28C], medulla with alectoronic, protocetraric and protolichesterinic acids as major substances; uncommon in secondary lowland rainforests)
- Lobes eciliate, medulla UV−, KC+ pink, mean ascospore length <20 µm .................................................................. P. odontatum (upper surface faintly to clearly effigurate white-maculate, medulla white throughout, apothecial disc imperforate, amphithecium smooth [Fig. 31D], medulla with protocetraric acid; uncommon at low elevations)
21. Thallus with isidia, without soredia ................................................................................................................................................ 22
- Thallus with soralia, with or without isidia .................................................................................................................................... 29
22. Medulla K+ yellow persistent, KC− (with stictic acid) .................................................................................................................. 23
- Other medullary reactions (stictic acid absent) .............................................................................................................................. 25
23. With conspicuous laciniae (up to 10 mm long), branched and easily shed ............................................................... P. nephophilum (lobe margins ciliate but cilia sometimes rare, upper surface faintly to clearly white-maculate, marginal and submarginal isidia that mostly develop early into phyllidia and branched laciniae [Fig. 29E]; fairly common species on Réunion, in montane and submontane rainforests)
- Without or with occasional short (up to 1.5 mm long) laciniae ..................................................................................................... 24
24. Average thickness of the cupular proper exciple <50 µm (Fig. 30C) ............................................................................. P. crinitum (lobe margins ciliate, upper surface faintly to clearly white-maculate, isidia marginal and laminal, granular to coralloid, often ciliate [Fig. 14E]; common species on Réunion, from submontane to subalpine belts)
- Average thickness of the cupular proper exciple> 55 µm .............................................................................................. P. occultum (phenotypically similar to P. crinitum, but differs by the greater thickness of the cupular proper exciple [Fig. 30C] and the ITS sequence; rare species on Réunion, in cloud forests)
25. Medulla K+ yellow then red (with salazinic acid) .................................................................................................... P. subisidiosum (lobe margins ciliate but cilia sometimes rare, upper surface conspicuously reticulate white-maculate [Fig. 40D], isidia mainly marginal and submarginal, coralloid; uncommon species on Réunion, in submontane and montane rainforests)
- Other medullary reactions (salazinic acid absent) .......................................................................................................................... 26
26. Medulla UV+ blue-white, KC+ fleeting purple pink, then pink-orange (with alectoronic acid) .................................... P. nemorum (morphotype with some laminal or submarginal isidia [Fig. 28D])
- Medulla UV–, KC– or KC+ pinkish (alectoronic acid absent) ...................................................................................................... 27
27. Medulla K−, KC+ pinkish (with protocetraric acid) ............................................................................................... P. subcorallinum (lobe margins ciliate, upper surface emaculate or faintly white-maculate, isidia mainly marginal and submarginal, coralloid or arbuscular, very often ciliate [Fig. 38D], medulla with protocetraric and protolichesterinic acids; uncommon in the windward part of Réunion, in the submontane belt)
- Medulla K+ slowly orange brown, KC− (with succinprotocetraric acid) ...................................................................................... 28
28. Thallus moderately adnate, lobes 2–13 mm wide ................................................................................................... P. mascarenense (lobe margins eciliate or irregularly ciliate, upper surface effigurate white-maculate, isidia marginal to laminal, simple to coralloid, occasionally ciliate [Fig. 22C], medulla with succinprotocetraric and fumarprotocetraric acids; fairly common on Réunion)
- Thallus adnate to tightly adnate, lobes 1–4 mm wide ....................................................................................................... P. orarium (looks more like a Canoparmelia s. lat. than a Parmotrema [Fig. 32D], lobe margins eciliate to weakly ciliate, upper surface effigurate white-maculate, isidia marginal to laminal, simple or ± branched, rarely ciliate, usually quickly sorediate [Fig. 32E], medulla with succinprotocetraric and fumarprotocetraric acids; in the southeastern part of Réunion, near the coast)
29. Medulla K+ yellow persistent, KC− (with stictic acid) ............................................................................................. P. nephophilum (sorediate morphotype, Fig. 29F)
- Other medullary reactions (stictic acid absent) .............................................................................................................................. 30
30. Medulla K+ yellow then red (with salazinic acid) ......................................................................................................................... 31
- Other medullary reactions (salazinic acid absent) .......................................................................................................................... 33
31. Upper surface emaculate, rarely faintly punctiform maculate; lower surface with a broad erhizinate marginal zone ....................... ....................................................................................................................................................................................... P. cristiferum (lobe margins eciliate to clearly ciliate, soralia mainly marginal, linear to labriform [Fig. 16D]; uncommon in the windward part of Réunion, at low elevation)
- Upper surface reticulate maculate; lower surface often with rhizines and papillae to the margins ............................................... 32
32. Marginal zone of the lower surface of sorediate lobes dark brown or black ....................................................... P. reticulatum aggr. (lobe margins ciliate, soralia mainly capitate at the tips of laciniae or submarginal ± linear at the apex of revolute lobes [Fig. 35F]; common and widespread on Réunion)
- Marginal zone of the lower surface of sorediate lobes often white or white mottled .......................................... P. cf. clavuliferum (lobe margins ciliate, soralia mainly capitate at the tips of laciniae [Fig. 12D]; uncommon species on Réunion)
33. Medulla K+ slowly orange brown, KC− (with succinprotocetraric acid) ...................................................................................... 34
- Medulla K− or K± yellowish, KC+ pinkish (with protocetraric acid) ........................................................................................... 35
34. Thallus adnate to tightly adnate, lobes 1–4 mm wide, isidia present (at least in the early stages of development) ........ P. orarium (looks more like a Canoparmelia s. lat. than a Parmotrema [Fig. 32D], lobe margins eciliate to weakly ciliate, upper surface effigurate white-maculate, isidia marginal to laminal, soralia marginal to laminal [Fig. 32F], often originating from rapid decay of young isidia, more rarely from pustules, occasionally orbicular or subcapitate, medulla with succinprotocetraric and fumarprotocetraric acids; in the southeastern part of Réunion, near the coast)
- Thallus moderately adnate, lobes 3–8 mm wide, isidia totally absent ............................................................. P. paramascarenense (lobe margins eciliate to irregularly ciliate, upper surface effigurate white-maculate, soralia terminal at the apex of tiny laciniae when young, then labriform or subcapitate, finally spreading submarginally on revolute lobes [Fig. 33D], medulla with succinprotocetraric and fumarprotocetraric acids; rare species on Réunion)
35. Medulla with echinocarpic acid ...................................................................................................................................... P. dilatatum (lobe margins eciliate or very sparsely ciliate, upper surface emaculate or faintly punctiform white-maculate, soralia marginal, linear to labriform when young, then subcapitate and ± coalescing on arbuscular rising structures [Fig. 19D], medulla with protocetraric and echinocarpic acids as major substances; very rare species on Réunion)
- Medulla without echinocarpic acid ................................................................................................................................................ 36
36. Medulla without protolichesterinic acid ......................................................................................................................................... 37
- Medulla with protolichesterinic acid .............................................................................................................................................. 38
37. Medulla UV+, with alectoronic acid ......................................................................................................................... P. cf. deflectens (lobe margins conspicuously ciliate, upper surface emaculate or faintly punctiform white-maculate, upper cortex fragile, flaking, soralia mainly marginal, linear to labriform [Fig. 18C], medulla with protocetraric and alectoronic acids as major substances; very rare species on Réunion)
- Medulla UV−, alectoronic acid absent ............................................................................................................................ P. robustum (lobe margins eciliate to ± irregularly ciliate, upper surface emaculate to punctiform white-maculate, soralia marginal at the apex of laciniae when young, then labriform or subcapitate and ± coalescing [Fig. 37D], medulla with protocetraric acid as major substance; common species on Réunion, mainly in montane rainforests)
38. Medulla UV+, with alectoronic acid ........................................................................................................................ P. subdeflectens (lobe margins conspicuously ciliate, upper surface emaculate or faintly punctiform white-maculate, soralia either terminal labriform or subcapitate on very short laciniae [Fig. 39C], or marginal and ± labriform [Fig. 39D], medulla with protocetraric, alectoronic and protolichesterinic acids as major substances; rare species on Réunion, in leeward submontane forests)
- Medulla UV−, without alectoronic acid ......................................................................................................................................... 39
39. Soralia submarginal, often pustulate (Fig. 42C), never marginal linear; upper cortex fragile, here and there flaking (Fig. 42D); soredia granulose (mean diameter> 50 µm) ............................................................................................................... P. udisilvestre (species of the P. subarnoldii group, lobe margins conspicuously ciliate, upper surface emaculate or faintly punctiform white-maculate, medulla with protocetraric and protolichesterinic acids as major substances; uncommon in the windward part of Réunion, in the submontane belt)
- Soralia marginal, linear discontinuous, then ± labriform (Fig. 9D & 20D), or subcapitate at the tip of very short laciniae (Fig. 20C), never pustulate; upper cortex not fragile; soredia subgranulose (mean diameter <45 µm) .......................................................... 40
40. Marginal cilia short (mean length <3.5 mm) .................................................................................................... P. brachyblepharum
- Marginal cilia long (mean length> 3.5 mm) ............................................................................................................... P. eleonomum (two species of the P. subarnoldii group, lobe margins conspicuously ciliate, upper surface emaculate or faintly punctiform white-maculate, medulla with protocetraric and protolichesterinic acids as major substances; rare species on Réunion)
description: Published as part of Masson, Didier, Magain, Nicolas & Sérusiaux, Emmanuël, 2024, Small island but great diversity: thirty six species of Parmotrema (Parmeliaceae, lichenized Ascomycota), including sixteen new species, on Réunion (Mascarenes), with additional data from the Western Indian Ocean, pp. 1-138 in Phytotaxa 657 (1) on pages 118-121, DOI: 10.11646/phytotaxa.657.1.1, http://zenodo.org/record/13217474