Lichen determination keys - podetiate lichens of highland Ecuador -

This unpublished key was prepared for a training course and is placed on the net to prevent it from getting forgotten in a drawer. It may be of some use to my fellow lichenologists. Comments are welcome at h.sipman@bgbm.org.

1a   Primary thallus (when present) fruticose, very similar to the 
     (pseudo)podetia, not conspicuously foliose; cephalodia usually
     present; usually growing on rock, often firmly attached
                                            STEREOCAULON (key)
 b   Primary thallus (when present) crustose or foliose, clearly
     distinct from the (pseudo)podetia, greenish above and white
     below; cephalodia absent; never firmly attached to rock         2

2a   Primary thallus crustose, always present; podetia usually under
     10 mm long; apothecium discs pink or occasionally brown         3
 b   Primary thallus squamulose, or absent; podetia often long, up to
     c. 10 cm; apothecium discs bright red or brown, rarely pink     9

3a   Apothecium discs brown; schizidia or soredia often present
                                       Baeomyces rufus (Huds.) Rebent.
 b   Apothecium discs pink; no schizidia or soredia                  4

4a (genus DIBAEIS) Apothecia flat, shortly stalked (podetium about as
     long as apothecium disc width)
                                 Dibaeis absoluta (Tuck.) Kalb & Gierl
 b   Apothecia convex from the beginning; podetium mostly much longer
     than the apothecium disc width                                  5

5a   Thallus granular to warty                                       6
 b   Thallus smooth or slightly granular                             7

6a   Thallus with scattered, white, c. 0.5 mm wide warts; podetia 1-4 
     mm long, mostly smooth
                             Dibaeis holstii (Müll. Arg.) Kalb & Gierl
 b   Thallus densely granular, granules c. 0.2 mm wide and pale gray;
     podetia 2-11 mm long, with granular surface
                               Dibaeis columbiana (Vain.) Kalb & Gierl

7a   Thallus dark gray, thick, areolated; apothecia 4-7 mm wide
                                   Dibaeis umbrelliformis Kalb & Gierl
 b   Thallus pale gray, thin and not areolated; apothecia 2-4 mm wide
                                                                     8

8a   Apothecia elongate, gradually narrowed towards the podetium;
     podetia 1-8 mm long          Dibaeis fungoides (Sw.) Kalb & Gierl
 b   Apothecia globose, suddenly narrowed towards the podetium;
     podetia 1-3 mm long              Dibaeis globulifera Kalb & Gierl

a   Apothecia pink, usually present; podetia to c. 2 mm long       10
 b   Apothecia bright red or (dark)brown, often absent; podetia
     usually over 10 mm long                                        11

10a (genus PHYLLOBAEIS) Primary thallus squamules much longer than
     wide and deeply lobed; mostly above 3000 m
                   Phyllobaeis imbricata (Hook. in Kunth) Kalb & Gierl
  b  Primary thallus squamules about as long as wide, crenulated;
     mostly below 3000 m           Phyllobaeis erythrella (Mont.) Kalb

11a  Podetial wall without compact inner layer, with many rounded
     perforations; cortex cartilaginous and occupying about half of
     the wall thickness; primary thallus usually absent             12
  b  Podetial wall with distinct, compact inner layer occupying half 
     of the wall thickness or more, without or with occasional slit-
     like perforations or open axils; cortex thin or absent; primary 
     thallus often present, sometimes without podetia               13

12a (genus CLADIA) Inner space of podetial cylinder empty; common 
     species of roadbanks and many other habitats
                                           Cladia aggregata (Sw.) Nyl.
  b  Inner space of podetial cylinder with thin arachnoid, dark gray 
     tissue of scattered hyphae; rare bog species
                                              Cladia fuliginosa Filson

13a  Primary thallus squamules always lacking; compact podetial cortex 
     always lacking, surface woolly; podetia richly branched        14
  b  Primary thallus squamules often present; compact podetial cortex 
     often present, at least at the base of the podetia, and there 
     surface smooth                                                 17

14a (genus CLADINA) Podetia predominantly trichotomously branching, 
     usually with a pale yellow tinge, forming rounded heads, P-
                              Cladina confusa (R. Sant.) Follm. & Ahti
  b  Podetia predominantly di- or tetrachotomously branching, whitish 
     gray or pale yellowish gray, growing in flat-topped mats; P+ red
                                                                    15

15a  Podetia pale yellowish gray, with usnic acid (K-, KC+ yellow) 
                                                Cladina boliviana Ahti
  b  Podetia whitish gray, with atranorin (K+ pale yellow, KC-)     16

16a  Podetia with weakly violet tinge, often strongly browned; tips 
     bluntish; hyaline pycnidial slime; preferably in open peat bogs
          Cladina rangiferina (L.) Nyl. ssp. abbayesii (Ahti) W. Culb.
  b  Podetia without violet tinge, not browned; tips subulate; red 
     pycnidial slime; in light forest
                                  Cladina arcuata (Ahti) Ahti & Follm.

a (genus CLADONIA) Primary thallus squamules large and dominant (in 
     well developed plants!)                                        18
  b  Podetia dominant, primary thallus squamules often small and 
     evanescent                                                     21

18a  Thallus P+ red, C-                                             19
  b  Thallus P-, C+ green           Cladonia strepsilis (Ach.) Grognot

19a  Thallus squamules sorediate; podetia, when present, hardly 
     standing out above the erect thallus squamules
                                                   Cladonia nana Vain.
  b  Thallus squamules not sorediate; podetia, when present, raised 
     above the spreading thallus squamules                          20

20a  Thallus often with white, marginal cilia; podetia often present, 
     subulate, with fragile, elongate, downward pointing squamules; 
     atranorin absent (K- or K+ brownish)
                                   Cladonia ceratophylla (Sw.) Spreng.
  b  Thallus without cilia; podetia usually absent, scyphose, without 
     fragile squamules; atranorin present (K+ pale yellow)
                                          Cladonia macrophyllodes Nyl.

21a  Most or all podetia scyphi-forming; scyphi usually more than 
     twice as wide as their stalks                                  22
  b  Podetia subulate, more or less branched; podetium tips may 
     occasionally show minute scyphi hardly wider than the podetium
                                                                    35

22a  Scyphi sprouting from the center, often forming chains of several 
     scyphi on top of each other                                    23
  b  Scyphi sprouting from the margin, usually single               27

23a  Podetium surface with fragile scales or granules, or sorediate
                                                                    24
  b  Podetium surface smooth                                        25

24a  Podetium surface with fragile scales, at least on underside of 
     scyphi margins; podetia composed of several, wide, short-stalked 
     scyphi                                    Cladonia andesita Vain.
  b  Podetium surface granular to sorediate; podetia composed of few 
     scyphi, often with subulate tips        Cladonia aleuropoda Vain.

25a  Margins of the scyphi with elongated, blackening, often 1-3 times 
     branching teeth                          Cladonia calycantha Nyl.
  b  Margins of the scyphi crenulate or shortly teethed             26

26a  Scyphi long and slender, c. 5-10 mm long and 0.5-3 mm wide; 
     podetia composed of few scyphi, often subulate; usually P-
                                             Cladonia isabellina Vain.
  b  Scyphi wider, 2-6 mm wide; podetia usually composed of many 
     scyphi, not subulate                     Cladonia rappii A. Evans

27a  Podetia with pale yellowish tinge, containing usnic acid (KC+ 
     yellow); apothecia red, when present
                                        Cladonia coccifera (L.) Willd.
  b  Podetia gray brown, without usnic acid (KC-); apothecia brown or 
     red                                                            28

28a  Podetia P+ red, K- or K+ brownish (fumarprotocetraric acid), 
     rarely P-, K-, or K+ pale yellow; hypothallus whitish, 
     inconspicuous                                                  29
  b  Podetia P+ yellow, K+ yellow (thamnolic acid); hypothallus 
     yellow, conspicuous (if K-, psoromic acid, see C. dactylota)   33

29a  Podetia P+ red, K+ brownish or rarely K+ pale yellow           30
  b  Podetia P-, K-                   Cladonia imbricarica Kristinsson

30a  Podetia sorediate, with more or less ecorticate granules       31
  b  Podetia not sorediate, with corticate, large granules only
                                      Cladonia pocillum (Ach.) Grognot

31a  Podetia finely sorediate on the scyphi margins, corticate at the 
     stalk, K+ yellow (atranorin) Cladonia humilis (With.) J.R. Laund. 
  b  Podetia sorediate to granular, also on the stalks, K- or K+ 
     brownish (no atranorin)                                        32

32a  Podetia finely sorediate on scyphi and stalk; soredial masses 
     often abraded and showing white podetium stereome
                                           Cladonia subsquamosa Kremp.
  b  Podetia coarsely sorediate on scyphi only, without white, abraded 
     spots             Cladonia chlorophaea (Flk. ex Sommerf.) Spreng. 
  (including some very similar but ecologically distinct species, 
     which require more complicated chemical tests for recognition, 
     like Cladonia cryptochlorophaea Asah. with cryptochlorophaeic 
     acid, and Cladonia grayi Merr. with grayanic acid).

33a  Podetia sorediate; scyphi narrow
                                 Cladonia leprocephala Ahti & Stenroos
  b  Podetia not sorediate, surface warty or with corticate granules
                                                                    34

34a  Podetia in part with narrow scyphi, in part subulate
                               Cladonia microscypha Ahti & S. Stenroos
  b  Podetia all with wide scyphi
                                Cladonia meridensis Ahti & S. Stenroos

a  Podetia sorediate, soredia sometimes mixed with granules or 
     squamules, often abraded and showing white stereome, simple or 
     scarcely branched                                              36
  b  Podetia without soredia, either with corticate granules or 
     fragile scales or squamules, often abraded, or with smooth 
     surface, scarcely or more richly branched                      43

36a  Usnic acid present, colour yellowish                           37
  b  Usnic acid absent, colour grey to brown                        38

37a  Axils of branched podetia often perforated and somewhat widened; 
     apothecia brown, rarely present  Cladonia scholanderi Des Abbayes
  b  Axils of branched podetia closed; apothecia red, often present
                                 Cladonia leprocephala Ahti & Stenroos

38a  Axils of branched podetia often perforated and somewhat widened
                                       Cladonia granulosa (Vain.) Ahti
  b  Axils of branched podetia closed                               39

39a  Soredia mostly in woolly clumps near the podetium tips; P+ yellow 
     (psoromic acid)                          Cladonia dactylota Tuck.
  b  Soredia dispersed over most of the podetium length, not woolly; 
     P+ red, yellow or P- (no psoromic acid)                        40

40a  Podetia P+ yellow, K+ yellow; apothecia and pycnidia, when 
     present, red                            Cladonia macilenta Hoffm.
  b  Podetia P+ red, K+ brownish or K-; apothecia and pycnidia, when 
     present, brown                                                 41

41a  Podetium stereome surface distinctly grooved; podetia often 
     largely abraded and showing a whitish to brownish stereome; 
     apothecia usually produced directly on subulate podetium tips
                               Cladonia corniculata Ahti & Kashiwadani
  b  Podetium stereome smoothly rounded; podetia mostly covered by 
     greenish masses of soredia and/or cortex; apothecia stalked on 
     terminal scyphi                                                42

42a  Podetia corticate in lower half and on lower side of scyphi; 
     sometimes with rounded soralia on transition between corticate 
     and sorediate part; soredia not coalescent
                                             Cladonia ochrochlora Flk.
  b  Podetia corticate only near extreme base, without rounded 
     soralia; soredia often coalescent into tiny squamules
                                   Cladonia subradiata (Vain.) Sandst.

a  Podetia to c. 1 cm long, always bearing apothecia              44
  b  Podetia usually several cm long, rarely a few bearing apothecia
                                                                    45

44a  Apothecia red; podetia very irregularly shaped; cortex of 
     squamules thick c. one third of total thickness
                                          Cladonia lopezii S. Stenroos
  b  Apothecia brown; podetia cylindrical, often once or a few times 
     verticillate-branched, all branches bearing apothecia; cortex of 
     squamules thin as usual                 Cladonia corymbosula Nyl.

45a  Podetia with corticate granules or fragile scales or squamules, 
     usually decorticated over much of their length                 46
  b  Podetia without fragile squamules, mostly corticate            50

46a  Axils of podetium branchings often perforate and dilated; with 
     squamules, without corticate granules or fragile scales (when 
     corticate granules present, see C. granulosa, lid 38)
                                      Cladonia squamosa (Scop.) Hoffm.
  b  Axils of podetium branchings closed; mostly with fragile scales 
     or squamules, sometimes also corticate granules                47

47a  Podetia mostly with naked, glassy, pale brown stereome; fragile 
     squamules usually elongate and pointing downward: apothecia and 
     pycnidia, when present, red; P+ yellow or P-
                                           Cladonia didyma (Fée) Vain.
  b  Podetia with mostly tomentose, white, abraded podetia; fragile 
     squamules often short and scale-like; apothecia and pycnidia, 
     when present, brown; P+ red                                    48

48a  Podetia with scattered, corticate patches, at tips forming small 
     scyphi, often very whitish, K+ pale yellow
                                               Cladonia mexicana Vain.
  b  Podetia without cortex, except sometimes at the base, at tips 
     always subulate, usually pale brownish; K+ brownish            49

49a  Podetia mostly subulate and unbranched, or with divaricate 
     branchlets, rarely with apothecium; stereome very hard, over most 
     of its length naked              Cladonia cartilaginea Müll. Arg.
  b  Podetia usually cylindrical and branched, or with terminal 
     apothecium, stereome less hard, tomentose where free, sometimes 
     slightly glassy                          Cladonia corymbites Nyl.

50a  Podetia yellowish to greenish grey, with usnic acid; KC+ yellow
                                                Cladonia aff. uncialis
  b  Podetia grey to brownish, without usnic acid, KC-               51

51a  Podetia P+ red, K+ brownish; podetia without perforated and 
     widened axils, fertile branches with lateral splits
                                      Cladonia furcata (Huds.) Schrad.
  b  Podetia P-, K- or P+ yellow, K+ yellow: podetia often with 
     widened and dilated axils. Cladonia crispata (Ach.) Flot.

List of Cladina and Cladonia species, with their principal lichen substances and colour reactions

• Cladina arcuata (Ahti) Ahti & Follm.: atranorin, fumarprotocetraric acid; P+ red, K+ pale yellow, C-, KC-.
• Cladina boliviana (Ahti) Ahti: usnic acid, fumarprotocetraric acid or rarely stictic acid; P+ red or orange, K+ brownish or orange, C-, KC+ yellow.
• Cladina confusa (R. Sant.) Follm. & Ahti: usnic and perlatolic acids or perlatolic acid alone; P-, K-, C-, KC+ yellow or KC-.
• Cladina rangiferina (L.) Nyl. ssp. abbayesii (Ahti) W. Culb.: atranorin, fumarprotocetraric acid; P+ red, K+ pale yellow, C-, KC-.
• Cladonia aleuropoda Vain.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia andesita Vain.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia calycantha Nyl.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia cartilaginea Müll. Arg.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia ceratophylla (Sw.) Spreng.: fumarprotocetraric acid, often with atranorin; P+ red, K+ brownish or K+ pale yellow, C-, KC-.
• Cladonia chlorophaea (Flk. ex Sommerf.) Spreng.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia coccifera (L.) Willd.: usnic acid, zeorin; P-, K-, C-, KC+ yellow.
• Cladonia corniculata Ahti & Kashiwadani: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia corymbites Nyl.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia corymbosula Nyl. (or C. tesselata Ahti & Kashiwadani?): fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia crispata (Ach.) Flot.: squamatic acid; P-, K-, C-, KC-.
• Cladonia cryptochlorophaea Asah.: fumarprotocetraric and cryptochlorophaeic acids; P+ red, K+ reddish, C, KC+ reddish.
• Cladonia dactylota Tuck.: psoromic acid; P+ yellow, K-, C-, KC-.
• Cladonia didyma (Fée) Vain.: barbatic or thamnolic and didymic acids; P- or P+ yellow, K- or K+ yellow, C-, KC-.
• Cladonia furcata (Huds.) Schrad.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia granulosa (Vain.) Ahti: thamnolic acid; P+ yellow, K+ yellow, C-, KC-.
• Cladonia humilis (With.) J.R. Laund.: atranorin, fumarprotocetraric acid; P+ red, K+ pale yellow, C-, KC-.
• Cladonia imbricarica Kristinsson: sphaerophorin; P-, K-, C-, KC-.
• Cladonia isabellina Vain.: homosekikaic, sometimes with fumarprotocetraric acid, or this only; P- or P+ red, K- or K+ brownish, C-, KC.
• Cladonia leprocephala Ahti & Stenroos: thamnolic acid; P+ yellow, K+ yellow, C-, KC-.
• Cladonia lopezii S. Stenroos: didymic acid; P-, K-, C-, KC-.
• Cladonia macilenta Hoffm. thamnolic and/or barbatic acid; P+ yellow or P-, K+ yellow or K-, C-, KC-.
• Cladonia macrophyllodes Nyl.: atranorin, fumarprotocetraric acid; P+ red, K+ pale yellow, C-, KC-.
• Cladonia meridensis Ahti & S. Stenroos: thamnolic acid; P+ yellow, K+ yellow, C-, KC-.
• Cladonia mexicana Vain.: atranorin, fumarprotocetraric acid; P+ red, K+ pale yellow, C-, KC-.
• Cladonia microscypha Ahti & S. Stenroos: thamnolic and didymic acids; P+ yellow, K+ yellow, C-, KC-.
• Cladonia nana Vain.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia ochrochlora Flk.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia pocillum (Ach.) Grognot: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia rappii A. Evans: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia scholanderi Abbayes: thamnolic acid; P+ yellow, K + yellow, C-, KC-.
• Cladonia squamosa (Scop.) Hoffm.: squamatic or thamnolic acid; P- or P+ yellow, K- or + yellow, C-, KC-.
• Cladonia strepsilis (Ach.) Grognot: squamatic and baeomycesic acid and strepsilin; P+ yellow, K-, C+ green, KC+ green.
• Cladonia subradiata (Vain.) Sandst.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia subsquamosa Kremp.: fumarprotocetraric acid; P+ red, K+ brownish, C-, KC-.
• Cladonia aff. uncialis (L.) Wigg.: usnic and thamnolic acids; P+ yellow, K + yellow, C-, KC-. (A rare species, which will be described soon as C. glabra Ahti)