Observation 134017: Heterodermia japonica (Sato) Swinscow & Krog
When: 2013-05-19
Collection location: Braga, Portugal [Click for map]
No herbarium specimen

Notes: On Fraxinus moss covered bark.

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Eye3 = Observer’s choice
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Heterodermia colors …
By: zaca
2013-05-21 14:41:35 CDT (-0400)

As you know, sometimes it is very difficult to say something definite regarding the color of a lichen. So, don’t let you guide only for this feature. On the other hand, depending on the genus under consideration, there could be a dramatic change in color due to hydratation, which is another point to take into account. This is just to say that terms like greenish, grey-whit, green-white, or greyish, can have the same or completely different meanings, depending on the
By the way, the British Flora, describes the color of the upper surface of H. japonica as ivory white … In addition, it is also written there, in the description of H. japonica, that “Moberg (2004) referred all British material to H. japonica, as H. obscurata differs in its spotted to arachnoid, orange, K+ purple, pigmented, underside”, which I interpret as being very difficult to distinguish the two species only based on the upper surface of thallus.

Zaca, I thought
By: Elsa (pinknailsgirl)
2013-05-20 18:32:34 CDT (-0400)

it would be noticed better on photo, there is only a little of the underside (upper left), but it was white with brownish yellow at the tips. At the time I didn’t know it was a decisive feature, I should have seen more lobes, and I usually bring some home, but in this case I forgot.

I read many descriptions, and I’m confused. some say that H. obscurata is gray-white and H. japonica is green-white but I see green and grey for the two in google photos.

However it’s my opinion that the description fits better for H. japonica, but of course I can’t be sure as lichens is a too new subject to me (I wasn’t even sure of being Heterodermia, so please help me)

The following descriptions are from this site: http://lichenportal.org/portal

H. japonica

“Thallus: foliose, very variable, irregular, rarely orbicular, up to 5 cm diam. (often forming colonies up to 15 cm or more in diam.), loosely adnate, dichotomously lobate.

lobes: sublinear, elongate, radiating, the lobe-tips ascending, usually widening towards apices, c. 2-3 (-4) mm at the tips, usually discrete, sometimes dissected with lobules along the margin developing small soralia.

upper surface: greenish white, whitish to cream-colored, rarely brownish, sometimes pruinose at tips especially when young, sorediate,

soredia: farinose to granular, in labriform to capitate soralia, on lateral or terminal lobes, sometimes spreading along lobe margin.
(…)

lower surface: white to brownish or bluish black, arachnoid, often sparsely spotted with a brownish orange-red pigment towards lobe apices, rhizinate; rhizines: marginal, simple, black, 1-3 (-7) mm long."
(…)

H. obscurata

“Thallus: foliose, forming ± orbicular rosettes or irregularly spreading, robust, 2-4 (-10) cm diam., ± firmly adnate, dichotomously to irregularly lobate.

lobes: c. 1-2 mm, radiating, sparsely divided, ± discrete, flat to slightly convex, minutely notched, eciliate.

upper surface: gray-white to rarely dark gray in center, shiny, not or rarely pruinose, sorediate.

soredia: granular, often rusty brown, in labriform to capitate soralia on lateral and terminal lobes, sometimes confluent and forming marginal soralia.
(…)

lower surface: felted with rust-colored or yellowish-brown pigment, K+ purple, not to be confused with the bluish-black underside present in H. japonica, arachnoid, rhizinate; rhizines: black, marginal, simple to squarrosely branched
(…)"

Underside?
By: zaca
2013-05-20 14:31:27 CDT (-0400)

Do you have a photo of the underside?
H. obscurata can be very similar and has yellowish underside.

Created: 2013-05-19 20:28:54 CDT (-0400)
Last modified: 2013-05-27 17:56:58 CDT (-0400)
Viewed: 39 times, last viewed: 2014-11-27 13:35:28 CST (-0500)
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