Observation 179423: Collema fragile Taylor

When: 2014-09-14

Collection location: Planalto das Cezaredas, Portugal [Click for map]

Who: zaca

No specimen available

This is certainly one of the rare species of Collema in Portugal. It has a distinguish feature, which however is difficult to observe, because the hialine hairs existing at the lobe tips are so to say “hidden” that only noticed them after arriving to the conclusion that no other possibility exist (at the full magnification of the attached photo one can see them). In fact, taking the dimensions into account (this specimen had about 2 cm in diameter), macroscopically there are some similar, like C. leptogioides, C. multipartitum and C. parvum. Two of them can be eliminated, the first one because lacks isida and the last one because was never observed fertile here. Concerning C. multipartitum it has spores of different shape (ellipsoid to fusiform and 3-septate).
I obtained the following dimensions for the spores:
(21.9) 26.9 – 35.1 (39.7) x (10.6) 11.3 – 14.2 (14.4) µm
Q = (1.6) 2.3 – 2.8 (3.1) ; N = 30
Me = 30.8 × 12.5 µm ; Qe = 2.5.


Microscopy: Apothecial section;
Microscopy: Apothecial section;
Microscopy: Apothecial section-details;
Microscopy: Hymenium;
Microscopy: Asci;
Microscopy: Spores.

Proposed Names

87% (1)
Recognized by sight
Used references: P. Carvalho, Collema, Sociedade Española de Liquenología, Flora Liquenológica Ibérica, vol. 10, 2012; British Flora: Smith et al., The Lichens of Great Britain and Ireland, British Lichen Society, 2nd ed., 2009.
Based on microscopic features

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= Observer’s choice
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