# Ramalina

Ramalina is a genus of greenish fruticose lichens that grow in the form of flattened, strap-like branches.$^{:189}$ Members of the genus are commonly called strap lichens$^{:189}$ or cartilage lichens. Apothecia are lecanorine.$^{:189}$
It is in the family Ramalinaceae and in the suborder Lecanorineae.

## Description

The genus Ramalina consists of shrubby (fruticose) lichens that often appear tufted, ranging from erect to hanging (pendulous) forms. The lobes of the thallus, which is the body of the lichen, typically emerge from a well-defined or more spread-out holdfast—a structure that anchors the lichen to its substrate. In rare cases, these lichens can be free-living, unattached to any surface. The branches within the thallus can vary from singular to many, and their branching pattern may be either regularly forked (dichotomous) or more irregular. These branches are commonly compressed and strap-shaped, although they can occasionally be rounded or symmetrical when viewed in cross-section. Some species may have channels, and a few can even develop window-like openings (fenestrations) or small, wart-like structures called papillae. In addition, the surface may be smooth or display ridges.
The outer layer of the thallus, the cortex, is typically thin and sometimes indistinct. Beneath the cortex lies a well-developed, cylindrical layer of interwoven fungal filaments hyphae), which is absent in species like Ramalina lacera. The inner side of this layer is often invaded by the photobiont layer, where the symbiotic algae reside. The algal partner in Ramalina lichens belongs to the trebouxioid group. The medulla, a loosely packed layer of hyphae beneath the photobiont, is usually airy and web-like (arachnoid) but can be denser or even absent in hollow branches.
Soralia—structures that produce asexual reproductive granules—are commonly found in Ramalina species. These granules can sometimes resemble tiny isidia, which are small, vegetative reproductive outgrowths. The reproductive structures where sexual reproduction occurs (apothecia), are usually short-stalked and located at or near the tips of the branches, often on the curved sections. The apothecia may range from concave to flat or convex as they age, with disc colours varying from pale yellow to pale green, brown, or pinkish-yellow, and sometimes covered with a white powdery coating (pruina). The edge of the apothecium, called the thalline margin, is usually present and may persist or become almost unnoticeable over time.
The asci, which are the spore-producing cells within the apothecia, are elongated and club-shaped, typically containing eight spores. These spores are one-septate, meaning they have a single division, and are broadly ellipsoidal or kidney-shaped, remaining colourless. Ramalina also produces asexual reproductive structures called pycnidia, which are tiny, flask-shaped bodies with an opening (ostiole) that may be pale or darkened. The cells within these pycnidia that generate conidia (asexual spores) are generally cylindrical, and the conidia themselves are rod-shaped, colourless, and without internal divisions (aseptate).
Chemically, Ramalina lichens often contain usnic acid, a compound that gives them a yellowish-green hue, along with various other substances, including depsides, depsidones, and aliphatic compounds. Lichen spot tests on the cortex are K−, C−, KC+ dark yellow, and P−.$^{:189}$

## Photobionts

Studies of photobiont diversity in Ramalina species have shown that they primarily associate with green algae from the genus Trebouxia. Research on Macaronesian Ramalina species found that they commonly partner with Trebouxia sp. TR9, which appears well-adapted to the higher temperatures and light intensities of these Atlantic islands. While multiple algal partners can coexist within a single lichen thallus, typically one photobiont species strongly dominates, accounting for over 90% of the algal cells present. The identity and relative abundance of photobionts appears to be more strongly influenced by geographic location and local climate than by the particular Ramalina species involved. This suggests that Ramalina fungi tend to associate with locally adapted photobionts rather than maintaining exclusive partnerships with specific algal species. Studies of R. farinacea have found that young thalli often contain more diverse algal communities compared to mature specimens, indicating that photobiont selection may be an ongoing process during lichen development.

## Distribution

The genus has a widespread distribution. A 2008 estimate placed more than 240 species in Ramalina.

## Species

* R. ailaoshanensis S.Y.Guo & L.F.Han (2021) – China
* R. alisiosae Pérez-Vargas & Pérez-Ort. (2013) – Canary Islands
* R. americana Hale (1979) [1978] – North America
* R. andina V.Marcano & A.Morales (1994) – Venezuela
* R. arabum (Dill. ex Ach.) Meyen & Flot. (1843)
* R. arsenii Sérus., van den Boom & Magain (2021) – Europe
* R. azorica Aptroot & F.Schumm (2008) – Azores
* R. australiensis Nyl. (1870)
* R. baltica Lettau (1912)
* R. banzarensis C.W.Dodge (1948)
* R. breviuscula (Nyl.) Nyl. (1872)
* R. caespitella G.N.Stevens (1986) – Australia
* R. calcarata Krog & Swinscow (1974) – East Africa
* R. calicaris (L.) Röhl. (1813)
* R. canalicularis (Nyl.) Kashiw. (2004)
* R. canariensis J.Steiner (1904)
* R. cannonii Elix, Laily & Samsuddin (1991) – Peninsular Malaysia
* R. capitata (Ach.) Nyl. (1872)
* R. carminae R.Arroyo & Seriñá (2011)
* R. celastri (Spreng.) A.Massal. (1861)
* R. chihuahuana Kashiw. & T.H.Nash (2002) – Mexico
* R. chiguarensis V.Marcano & A.Morales (1994) – Venezuela
* R. chondrina J.Steiner (1904)
* R. cinereovirens Kashiw., K.H.Moon & J.E.Han (2021) – South Korea
* R. confirmata (Nyl.) Zahlbr. (1930)
* R. coreana Kashiw. & K.H.Moon (2002) – Southeast Asia
* R. corymbosa (Hue) Kotlov (2004)
* R. crispata V.Marcano & A. Morales (1994) – Venezuela
* R. cuspidata (Ach.) Nyl. (1870)
* R. darwiniana Aptroot & Bungartz (2007) – Galapagos
* R. dilacerata (Hoffm.) Hoffm. (1825)
* R. disparata Krog & Swinscow (1976) – Africa
* R. dissimilis Krog (2000) – Tanzania
* R. dumeticola Krog & Swinscow (1976) – Africa
* R. europaea Gasparyan, Sipman & Lücking (2017) – Europe
* R. exiguella Stirt. (1881)
* R. exilis Asahina (1939) – Japan
* R. farinacea (L.) Ach. (1810)
* R. fastigiata (Pers.) Ach. (1810)
* R. fecunda Krog & Swinscow (1976) – Africa
* R. filicaulis G.N.Stevens (1987) – Australia
* R. fimbriata Krog & Swinscow (1974) – East Africa
* R. fissa (Müll.Arg.) Vain. (1900)
* R. fragilis Aptroot & Bungartz (2007) – Galapagos
* R. fraxinea (L.) Ach. (1810)
* R. furcellangulida Aptroot (2007) – Galapagos
* R. galapagoensis Follmann (1968)
* R. gallowayi Kashiw., T.H.Nash & K.H.Moon (2007)
* R. geniculatella Aptroot (2008) – Saint Helena
* R. glaucescens Kremp. (1881)
* R. gloriosensis R.Poncet (2021) – Scattered Islands
* R. hengduanshanensis S.O.Oh & Li S.Wang (2014)
* R. hivertiana R.Poncet (2021) – Scattered Islands
* R. hoehneliana Müll.Arg. (1890)
* R. hyrcana Sipman (2011)
* R. inclinata Kashiw., K.H.Moon & M.J.Lai (2006)
* R. inflata (Hook.f. & Taylor) Hook.f. & Taylor (1845)
* R. intermedia (Delise ex Nyl.) Nyl. (1873)
* R. intestiniformis Kashiw. & K.H.Moon (2016) – Korea
* R. ketner-oostrae Aptroot (2008) – Saint Helena
* R. krogiae Guissard & Sérus. (2020) – Canary Islands
* R. labiosorediata Gasparyan, Sipman & Lücking (2017) – North America
* R. lacera (With.) J.R.Laundon (1984)
* R. leiodea (Nyl.) Nyl. (1888)
* R. leptocarpha Tuck., 1858
* R. litorea G.N.Stevens (1986)
* R. lopezii V.Marcano & A.Morales (1994) – Venezuela
* R. luciae Molho, Bodo, W.L.Culb. & C.F.Culb. (1981)
* R. mahoneyi Quedensley & M.Véliz (2011)
* R. maritima Krog & Swinscow (1976) – Africa
* R. marteaui R.Poncet (2021) – Scattered Islands
* R. menziesii Taylor (1847)
* R. meridionalis Blanchon & Bannister (2002)
* R. microphylla V.Marcano & A.Morales (1994) – Venezuela
* R. nervulosa (Müll.Arg.) Abbayes (1952)
* R. obtusata (Arnold) Bitter (1901)
* R. osorioi Kashiw., T.H.Nash & K.H.Moon (2007)
* R. pacifica Asahina (1939) – Japan
* R. panizzei De Not. (1846)
* R. peruviana Ach. (1810)
* R. pollinaria (Westr.) Ach. (1810)
* R. polyforma Aptroot (2007) – Galapagos
* R. polymorpha (Lilj.) Ach. (1810)
* R. portuensis Samp. (1924)
* R. psoromica Kashiw. & T.H.Nash (2002) – Mexico
* R. qinlingensis S.Y.Guo & L.F.Han (2021) – China
* R. quercicola Kashiw. & T.H.Nash (2004)
* R. reducta Krog & Swinscow (1976) – Africa
* R. reptans Kashiw., C.W.Sm. & K.H.Moon (2002) – Hawaii
* R. rigidella Aptroot (2008) – Saint Helena
* R. ryukyuensis Kashiw. & K.H.Moon (2017) – Japan
* R. sanctae-helenae Aptroot (2008) – Saint Helena
* R. santanensis V.Marcano & A.Morales (1994) – Venezuela
* R. sarahae K.Knudsen, Lendemer & Kocouk. (2018) – Channel Islands (California)
* R. seawardii Aptroot & Sipman (2001) – Hong Kong
* R. sideriza Zahlbr. (1911)
* R. siliquosa (Huds.) A.L.Sm. (1918)
* R. sphaerophora Kashiw. & K.H.Moon (2016) – Korea
* R. stevensiae Elix, Laily & Samsuddin (1991) – Norfolk Island
* R. stoffersii Sipman (2011)
* R. subdecumbens Kashiw., K.H.Moon & J.E.Han (2021) – South Korea
* R. subfarinacea (Nyl. ex Cromb.) Nyl. (1872)
* R. subfraxinea Nyl. (1870)
* R. subrotunda Kashiw., C.W.Sm. & K.H.Moon (2002) – Hawaii
* R. tapperii Krog & Swinscow (1974) – East Africa
* R. tenella Müll.Arg. (1879)
* R. tenuissima V.Marcano & A.Morales (1994) – Venezuela
* R. throwerae Aptroot & Sipman (2001) – Hong Kong
* R. tovarensis V.Marcano & A.Morales (1994) – Venezuela
* R. translucida Krog & Swinscow (1974) – East Africa
* R. tropica G.N.Stevens (1987) – Australia
* R. unilateralis F.Wilson (1889)
* R. usnea (L.) R.Howe (1914)
* R. whinrayi G.N.Stevens (1986) – Australia
* R. wirthii Aptroot & Schumm (2008) – Azores
* R. yokotae Kashiw. & K.H.Moon (2017) – Japan
* R. zollingeri Szatala (1937)
* Ramalina farinacea
* Ramalina fastigiata
* Ramalina fraxinea
* Ramalina siliquosa (with crustose lichen around it)