Observation 210774: Cercidospora lobothalliae Nav.-Ros. & Calat.
When: 2015-02-14
(37.2439° -118.5934° 771m)

Notes: On steep north face of granite cliff; perithecia globose, immersed in center of host apothecia taking up most of hymenium, to ~200um wide; exciple green-black-brown near top, otherwise hyaline; hymenium hyaline, I-, K/I-; hamathecium of loose septate ~simple hyphae; asci cylindrical, ~60×15um, with slightly thickened tip and small ocular chamber, I-, K/I-; spores 4-8 per ascus, simple, hyaline, often somewhat attenuate at one end, ~20-25×5-6um.

Images

540567
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at 20x, stacked
540568
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at 40x, stacked
540569
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perithecium section, in water, at 100x
540570
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perithecium section, in water, at 100x
540571
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perithecium section, in water and I, at 400x
540572
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perithecium section, in water, at 400x
540573
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spores, in water, at 400x
540574
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spores and asci, in K/I, at 400x

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Comments

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I’m still trying to get to the bottom of this specimen
By: Jason Hollinger (jason)
2015-07-20 13:15:45 PDT (-0700)

The host is wrong: true C. lobothalliae should grow within the thallus of Lobothallia species. This is exclusively in the center of young apothecia of an undescribed Aspicilia sp.

I call the host “Aspicilia cf. americana”: it is common in the Great Basin on siliceous rocks mostly at mid-elevations, K-, 8 large spores, mid-length conidia. It comes out A. americana in the Sonoran Flora, but having now seen true A. americana (from Chiricahua Mountains where it is common), I can state very confidently that this species is morphologically quite different, even if chemistry, spores and conidia all match.

The only species of Cercidospora known to have exclusively simple spores is C. lobothalliae, making this specimen very easy. The only question appears to be whether this novel habit/host is sufficient grounds for calling it a new species. It seems Cercidospora in general are fairly particular about host. It is also possible that the spores of this specimen are longer than typical C. lobothalliae.

I have one additional specimen on the same host from a location approximately 30 miles to the north (JH 7292).

Created: 2015-07-20 13:08:24 PDT (-0700)
Last modified: 2015-07-20 13:08:31 PDT (-0700)
Viewed: 14 times, last viewed: 2016-10-21 03:30:36 PDT (-0700)
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