Xenolecia cataractarum
Family
Lecideaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | Data Deficient | Qualifiers: IE, OL
Distribution
Campbell Island (Mt Honey).
Habitat
The new species is known only from the type locality on Mt Honey, Campbell Island, New Zealand, where it is apparently quite frequent on siliceous rocks near a waterfall (Imshaug made four separate collections from there, along with several duplicates).
Detailed description
Thallus creamy white, with a distinct, obscurely effigurate margin with a blue-black prothallus; medulla I−. Photobiont chlorococcoid, arranged in loosely defined vertical bundles; cells globose to slightly ovoid, sometimes irregularly shaped and angular (presumably disrupted), 5–7(–9) µm across. Apothecia numerous, black, innate with a concave disc, 0·2–0·5mm diam.; proper margin not apparent but disc often surrounded by a blue-grey border, 0·05mm wide, that is formed by the thallus cortex overreaching the epihymenium. Proper exciple poorly developed, annular, 10–15 µm wide, very dilute orangebrown, structure unclear but apparently little differentiated from the hymenium. Hypothecium dilute brown to dark brown, upper part composed of vertically arranged hyphae, lower part ±cellular, extending into the thallus for up to 160 µm. Hymenium c. 220–250 µm tall; paraphyses slender (1 µm wide), sparingly branched and anastomosing, not or only slightly swollen at the apex; epihymenium olivaceous (N+ red, K± brown; probably Cinereorufa-green and Arnoldiana-brown). Asci cylindrical-clavate, 50–60 × 15–18 µm, outer wall I+ blue, immature asci initially with a distinct I+ blue cap, occasionally with a less distinct ring structure extending down into the tholus, mature asci Porpidia-type, similar to that of X. spadicomma; ascospores simple, hyaline, with a thin gelatinous sheath (halonate), broadly ellipsoid, (12–)14·84±1·65(–18) × (6–) 6·91±1·02(–9) µm; l/w ratio 1·67–3·00, mean = 2·20, (n = 16). Conidiomata pycnidia, black, immersed, abundant at the thallus edge when two thalli meet; conidia hyaline, filiform, 20–25 × 1 µm (n = 10).
Chemistry: K+ red, C−, KC−, PD+ yellow, UV+ dull white; norstictic acid by TLC.
Similar taxa
Differs from Xenolecia spadicomma Hertel in having much smaller apothecia and ascospores, a greenish pigment in the epihymenium, a non-amyloid medulla and in the production of norstictic acid.
Substrate
Saxicolous
Etymology
cataractarum: Named after the habitat of the only collection (Latin: ‘cataractarum’ = of waterfalls)
Attribution
Fact sheet prepared by Marley Ford (17 November 2022). Brief description, Distribution, Habitat, and Features sections copied from Fryday & Thus (2017).
References and further reading
Fryday A.M. and Thus H. 2017: The genus Xenolecia (Lecideaceae s. lat., Lecanoromycetidae inc. sed.), including a second species in the genus from Campbell Island, New Zealand. The Lichenologist, 49(4): 365-372.