Allographa upduna is a species of bark-dwelling script lichen in the family Graphidaceae. It forms a smooth, greenish-grey to grey crust and produces isidia, small coral-like outgrowths used for asexual reproduction. The fruiting bodies are elongated and slit-like, typical of script lichens. The species grows in the semi-evergreen forests of Arunachal Pradesh in northeastern India.
Allographa upduna was originally described as Hemithecium isidiatum by Dalip Kumar Upreti and Urvashi Dubey in a 2011 paper co-authored with Sanjeeva Nayaka. The holotype was collected on bark in Kago-kashi forest near Kabu village (West Siang District, Arunachal Pradesh) on 20 March 2006 and is housed in the herbarium of the National Botanical Research Institute in Lucknow (LWG). In the original publication, the species was classified in Hemithecium, which contained 44 species worldwide at that time. Described as the first known member of Hemithecium, it was also characterized by its hyaline (colourless), (multi-chambered) ascospores and the presence of salazinic acid. The epithet isidiatum refers to the isidia on the thallus.
Robert Lücking and Klaus Kalb later introduced the replacement name Allographa upduna for Hemithecium isidiatum. The original epithet could not be used in Allographa because it would conflict with the already-published name Allographa isidiata. The name upduna is formed from the initials of the authors of the original description (Upreti, Dubey, and Nayaka).
Allographa upduna is a crustose lichen that forms a smooth, thick crust that is greenish grey to grey, sometimes becoming greyish-brown to pale brown. The thallus produces isidia (small outgrowths used for vegetative reproduction) that are simple to -branched, about 0.2âÂÂ0.4 mm in diameter and 0.3âÂÂ1.0 mm tall, and the same colour as the thallus and readily detached.
The fruiting bodies are (elongate, slit-like apothecia) that are greyish white to grey, prominent and emergent, mostly , and typically 1âÂÂ4 mm long and 0.25âÂÂ0.5 mm wide. Their rim (the ) is non- and colourless to pale yellowish-brown; it has a narrow basal region and a broader upper region marked by several grooves (). The are convergent and entire, irregular on the outer side, and covered by a thalline veil up to the top; crystals also occur above the exciple. The is dark brown and 6âÂÂ9 üm high, while the hymenium is hyaline, not , and 80âÂÂ120 üm high; beneath it is a pale yellow to yellow about 14âÂÂ18 üm high. The asci contain 4âÂÂ8 spores and measure about 45âÂÂ77 üm long and 13âÂÂ20 üm wide. The ascospores are hyaline, oblong-ellipsoid and , with 6âÂÂ17 transverse septa and 1âÂÂ5 longitudinal septa, measuring 14âÂÂ27(âÂÂ35) à6âÂÂ8 üm, and they show an iodine staining reaction described as I+ blue. Thin-layer chromatography detected salazinic acid in the thallus.
Allographa upduna may be confused with Platythecium dimorphodes because of the lirellae morphology and the presence of isidia, but that species has smaller spores (9âÂÂ16 à5âÂÂ8 üm) and contains norstictic and connorstictic acids. It is close to Hemithecium microspermum in ascospore size and shape, but that species differs in having a non-striate or weakly striate exciple and different lichen substances (constictic, hyposalazinic, norstictic and stictic acids). Hemithecium salacilabiatum also contains salazinic acid but lacks isidia and has much larger spores (130âÂÂ200 à35âÂÂ60 üm).
Allographa upduna has been reported from semi-evergreen forests in the West Siang District of Arunachal Pradesh in the eastern Himalayan region of India. The species was recorded between 250 and 500 m elevation. It grows mostly on smooth-barked trees in moist, humid sites. In the type area it was found growing with other lichens including Graphis scripta, Sarcographa labyrinthica, Phaeographis dendritica, and various pyrenocarpous lichens.