Dictyonema krogiae

Last updated

Dictyonema krogiae
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hygrophoraceae
Genus: Dictyonema
Species:
D. krogiae
Binomial name
Dictyonema krogiae
Lücking & Timdal (2016)

Dictyonema krogiae is a species of basidiolichen in the family Hygrophoraceae. [1] It is found in Kenya, where it grows as an epiphyte on trees. It is often found in association with other lichens, such as Parmotrema , and bryophytes, such as Frullania . A main characteristic that distinguishes it from other closely related species is its clearly defined internal layers, including its contrasting dense photobiont layer and a loose lower cortex . [2]

Contents

Taxonomy

The lichen was formally described as a new species by lichenologists Robert Lücking and Einar Timdal in 2016. The type specimen was collected from a moist deciduous forest on Mount Kenya (Kirinyaga County, Central Province) at an elevation of 2,000 m (6,600 ft). The species epithet honours Norwegian lichenologist Hildur Krog, "for her invaluable contributions to African lichenology". [2] The type locality is quite rich in species, and Krog made nearly 200 collections there. [2]

Dictyonema krogiae is a member of the Dictyonema sericeum species complex, a group of species sharing similar overall morphology, including shelf-like, filamentous lobes. [2]

Description

The thallus of the lichen is filamentous and forms semi-circular shapes that can range from adnate to projecting shelves up to 10 cm (4 in) across, with single lobes 1–6 cm (0.4–2.4 in) wide. The fibrils are densely arranged, horizontally radiating and parallel, and are a dark greenish-blue (aeruginous) color without or with indistinct spaces in between. The thallus has a thick, byssoid , irregularly interlaced medulla, known as a hypothallus , which is visible as a narrow line along the margin and strongly contrasts with the aeruginous fibrils. [2]

Viewed microscopically in cross-section, the thallus is 400–500 μm thick and ecorticate, meaning that it lacks a distinct outer layer. The photobiont layer is fully exposed and well-defined, with a thickness of 100–150 μm. The medulla, made up of very loosely woven hyphae, is 200–300 μm thick, and there is a lower "cortex" composed of more densely woven hyphae that is about 50 μm thick. The photobiont layer consists of numerous, periclinally arranged, parallel fibrils formed by cyanobacterial filaments wrapped in a closed hyphal sheath of jigsaw-puzzle-shaped cells. The fibrils are 15–20 μm wide, with a hyphal sheath that is 2–3 μm thick. The cyanobacterial filaments are composed of 12–15 μm wide and 5–7 μm high, aeruginous green cells penetrated by tubular fungal hyphae. The heterocytes , sparse in distribution and ranging from hyaline to yellowish, measure 11–13 μm wide and 4–6 μm high. Cells of the hyphal sheath, undulating in profile, have a diameter of 3–5 μm. In surface fibrils and towards the thallus margin, they are often shallowly verrucose - papillose . The hyphae of the medulla, lower "cortex" (hypothallus), and white bordering line (prothallus) are straight, much branched, and 4–6 μm thick, lacking clamp connections. [2]

In Dictyonema krogiae, the hymenophore, which is the spore-producing structure, is only modestly developed. It manifests as soft, irregular patches of effuse or flattened growth on the thallus underside, bearing resupinate characteristics. These patches have a diameter of 0.5–1 mm, are slightly convex, and have a whitish, smooth surface with indistinct margins. Viewed in microscopic cross-section, the hymenophore is 70–150 μm thick and is composed of a paraplectenchymatous tissue layer resting on strongly agglutinated, 4–6 μm thick, generative hyphae that emerge from the supporting thallus. The hymenium is composed of numerous, palisade-like basidioles and scattered basidia. The basidioles are 20–30 by 5–6 μm, and the basidia are 30–40 by 5–7 μm and have 4 sterigmata. Only a few basidiospores have been documented; they are ellipsoid, hyaline, lack any septa, and measure 7–10 by 3–4 μm. [2]

Related Research Articles

<i>Psora</i> Genus of lichens

Psora is a genus of lichen-forming fungi in the family Psoraceae. Members of the genus are commonly called fishscale lichens. Lichens in the genus Psora generally have a squamulose thallus and anthraquinones in the hymenium. Photobiont partners of Psora lichens include members of the green algal genera Asterochloris, Chloroidium, Myrmecia, and Trebouxia.

Dictyonema is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.

Dictyonema hernandezii is a species of basidiolichen in the family Hygrophoraceae. Found in montane rainforests of Costa Rica and in Colombia, it was described as new to science in 2011. The specific epithet hernandezii honours Venezuelan lichenologist Jesús Hernández.

<span class="mw-page-title-main">Lichen morphology</span>

Lichen morphology describes the external appearance and structures of a lichen. These can vary considerably from species to species. Lichen growth forms are used to group lichens by "vegetative" thallus types, and forms of "non-vegetative" reproductive parts. Some lichen thalli have the aspect of leaves ; others cover the substrate like a crust, others such as the genus Ramalina adopt shrubby forms, and there are gelatinous lichens such as the genus Collema.

<i>Punctelia graminicola</i> Species of lichen

Punctelia graminicola is a species of foliose (leafy) lichen in the family Parmeliaceae. It grows on rocks, and, less frequently, on bark in North America, South America, and East Africa. It has a blue-grey thallus measuring up to about 15 cm (6 in), covered with tiny pores called pseudocyphellae. Sometimes the lichen forms small lobes that project out from the surface. Fruiting bodies are uncommon in this species; if present, they resemble small cups with a brown internal disc measuring 3–10 mm (0.1–0.4 in) in diameter. A lookalike species, Punctelia hypoleucites, is not readily distinguishable from Punctelia graminicola by appearance or habitat alone; these species can only be reliably differentiated by examining the length of their conidia.

Leptogium compactum is a species of corticolous (bark-dwelling), foliose lichen in the family Collemataceae. Found in northwestern North America, it was formally described as a new species in 2016 by Daphne Stone, Frances Anderson, and James Hinds. It is distinguished from related Leptogium species by the tightly packed hyphae in the medulla; this characteristic internal anatomy is alluded to in the species epithet compactum.

Cyphellostereum bicolor is a species of corticolous (bark-dwelling) basidiolichen in the family Hygrophoraceae. Found in Mauritius, it was formally described as a new species by lichenologists Robert Lücking and Einar Timdal. The type specimen was collected from the Bambou Mountains at an elevation of 250–300 m (820–980 ft), where it was found growing on tree bark. The species epithet bicolor refers to the notable visual contrast between the vivid blue-green cyanobacterial filaments and the white hyphal patches that give rise to the hymenophore.

Dictyonema album is a species of basidiolichen in the family Hygrophoraceae. It is found in Mauritius, where it grows as an epiphyte on shrubs.

Dictyonema tricolor is a species of basidiolichen in the family Hygrophoraceae. It is found in Tanzania, where it grows as an epiphyte on trees. The lichen was formally described as a new species by lichenologists Robert Lücking and Einar Timdal. The type specimen was collected by Norwegian Hildur Krog from a low montane rainforest in Lulandu Forest, at an elevation of 2,000 m (6,600 ft). The species epithet refers to the three-colours displayed where the regularly ascending tufts of blue-green cyanobacterial fibrils meet the brown or white colour in the apical part of the tufts.

Dictyonema ramificans is a basidiolichen species in the family Hygrophoraceae. Discovered in 2010 in the Galapagos Islands, it was formally described as a new species in 2017 by lichenologists Manuela Dal-Forno, Alba Yanez-Ayabaca, and Robert Lücking. Its species epithet is derived from the branching pattern of the fibrils that form a net-like structure, giving it an arachnoid (cobweb-like) appearance. This species has only been found in the humid zone of Santa Cruz Island, growing exclusively on bryophytes. While it is similar to other Dictyonema species, it differs in its unique fibril branching pattern and erect arachnoid structure.

Heppia arenacea is a species of terricolous (ground-dwelling) lichen in the family Lichinaceae. Discovered in Yemen, it is characterized by its sand-coloured thallus and the incorporation of soil particles throughout its vegetative parts. The lichen is found in soil crust communities over limestone and basaltic rock in desert habitats, as well as in partially sheltered areas between large boulders.

Dictyonema aeruginosulum is a species of basidiolichen in the family Hygrophoraceae. Characteristics of the lichen include its distinctive finger-like projections and blue-green hue. It is distinguishable from its closest relatives by its unique morphology and the absence of clamp connections in its structure. Dictyonema aeruginosulum is an epiphyte, forming thick mats on tree trunks within rainforest regions. The species was first identified in Costa Rica's Tenorio Volcano National Park, and it has only been recorded from this location.

Dictyonema metallicum is a species of basidiolichen in the family Hygrophoraceae. It is found in the montane rainforests of Ecuador. Characterised by its metallic shimmer, it is an epiphytic lichen that spans large areas on host tree trunks and frequently extends to adjacent bryophytes. Its unique visual texture is created by the loosely interwoven dark blue fibrils of the thallus, a thin, compressed filamentous layer, accentuated by a silver prothallus.

Dictyonema obscuratum is a species of basidiolichen in the family Hygrophoraceae. Originally discovered in Brazil and later recorded in Bolivia and Colombia, its cryptic, olive-green thallus sets it apart from similar species like Dictyonema phyllophilum and D. schenckianum.

Neosergipea septoconidiata is a species of corticolous (bark-dwelling) lichen in the family Roccellaceae. It is a unique species of lichen that grows on the bark of trees in the primary forests of Brazil with its bluish-grey thallus and bright orange pycnidia that have a fluffy hyphal surface.

Anaptychia ethiopica is a species of lichen in the family Teloschistaceae. Found in East Africa, China, and Russia, it was formally described as a new species in 1976 by lichenologists Thomas Douglas Victor Swinscow and Hildur Krog. The type specimen was collected from Mount Bwahit, where it was found growing on moss.

Dictyonema yunnanum is a little-known species of basidiolichen in the family Hygrophoraceae. Found in a tropical area in Southwestern China, this species is characterised by its filamentous, micro-fruticulose thallus. A main distinguishing feature is the presence of erect fibrils with silvery or white tips.

Caloplaca lecanorocarpa is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae. Found in Brazil, it was formally described as a new species in 2016 by the lichenologists André Aptroot and Marcela Cáceres. It is named for its overall appearance to lichens in the Lecanora subfusca species complex.

Lecidea toensbergii is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae. Described as a new species in 2018, it has been documented from several locations in Norway and a single location in Sweden, where it grows in rocky alpine environments.

Pyrenothrix is a small genus of lichen-forming fungi in the family Pyrenotrichaceae. It comprises two species of filamentous lichens, which are organisms formed by a symbiotic relationship between fungi and photosynthetic partners. The genus is characterized by its unique structure, featuring densely arranged filaments composed of cyanobacteria wrapped in fungal threads. Pyrenothrix species form dark greyish-brown growths on various surfaces, with one species found on tree bark and the other on leaves in tropical forests. The genus was circumscribed in 1917 by American scientist Lincoln Ware Riddle, based on specimens collected in Florida. Pyrenothrix is distinguished from other lichens by its intricate cellular structure and reproductive features, including specialized spore-producing structures.

References

  1. "Dictyonema krogiae Lücking & Timdal". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 11 June 2023.
  2. 1 2 3 4 5 6 7 Lücking, Robert; Timdal, Einar (2016). "New species of Dictyonema and Cyphellostereum (lichenized Basidiomycota: Hygrophoraceae) from tropical Africa and the Indian Ocean, dedicated to the late Hildur Krog". Willdenowia. 46 (1): 191–199. doi: 10.3372/wi.46.46115 .