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Lichens (1985) - Flora of New Zealand Lichens
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Stereocaulon Hoffm.

STEREOCAULON Hoffm., 1796  nom. cons. 

Thallus dimorphic. Primary thallus crustose, granular, verrucose or squamulose, soon disappearing, very seldom persistent. Pseudopodetia erect, usually branched, often complex, springing from a ± well- developed holdfast in some species, corticate or ± completely decorticate, covered with verrucae, or simple or branched phyllocladia which are usually terete and corticate. Medulla loosely woven, containing colonies of a green Protococcoid alga, chondroid axis of thick-walled longitudinal hyphae. Cephalodia abundant to rare, a characteristic feature of the genus, containing a blue-green alga (Stigonema, Scytonema or Chroococcus). Apothecia lecideine terminal, disc frequently convex, occasionally plane and marginate, brown or red-brown to black. Hypothecium usually colourless, brown in some species. Paraphyses simple. Asci clavate to cylindrical, 8-spored. Ascospores colourless thin-walled, elongate-ellipsoid to cylindrical-fusiform or vermiform, transversely 1-13-septate. Pycnidia terminal or lateral, immersed, ovoid to spherical, darkened about the ostiole. Conidia filiform to cylindrical, straight or curved.

Key

1
Phyllocladia with dark centres and pale margins
vesuvianum
Phyllocladia without dark centres
2
2
Pseudopodetia 0.3-3 (rarely to 6) cm tall
3
Pseudopodetia (1-)3-25 cm tall
6
3
Pseudopodetia (1-)3-10 mm tall, mainly simple, phyllocladia absent
4
Pseudopodetia to 3 (rarely to 6) cm tall, phyllocladia present or absent
5
4
Cephalodia persistently pale, wrinkled-scrobiculate, apothecia convex, immarginate, hypothecium colourless
gregarium
Cephalodia brown-black, scabrid, apothecia plane, distinctly marginate, hypothecium brown
caespitosum
5
Pseudopodetia simple or sparingly branched, to 3 cm tall, phyllocladia and soredia absent, cortex continuous, distinctly verrucose-areolate
loricatum
Pseudopodetia branched, never simple, phyllocladia present, ± sorediate, cortex continuous or in flaky patches
corticatulum
6
Phyllocladia flattened, paler on under side, hypothecium brown
fronduliferum
Phyllocladia terete, hypothecium colourless
7
7
Cephalodia distinctly stalked
8
Cephalodia sessile or only very slightly stalked
9
8
Cortex of pseudopodetia verruculose-areolate, apices and phyllocladia sometimes sorediate, spores (1-)3-4-septate
trachyphloeum
Cortex of pseudopodetia smooth to wrinkled, apices and phyllocladia never sorediate, spores (5-)6-9(-13)-septate
colensoi
9
Phyllocladia numerous, cephalodia large, irregular-wrinkled, apothecia small, disc convex, red-brown
ramulosum
Phyllocladia sparse, cephalodia small, globose, sparse, apothecia large, disc plane to subconvex, brown-purple to black
argus

Stereocaulon is a genus of c. 123 species of wide distribution [Dodge Annls cryptog. exot. 2: 93-153 (1929); Lamb Can. J. Bot. 29: 522-584 (1951); J. Hattori bot. Lab. 43: 191-255 (1977)] 10 of which occur in New Zealand. Of this number five appear to be endemic [Galloway et al., Lichenologist 8: 61-67 (1976); Galloway Bot. Notiser 133: 261-279 (1980)]. Species are saxicolous or terricolous, and colonise a wide range of rock and soil types. Typifications of New Zealand taxa are given in Galloway (1980, loc. cit. ).

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