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Collema
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<h2 id="description">Description</h2> <p>Collema lichens are characterized by their medium to large size, with a diameter of 3 to 20 cm (1 to 8 in). They have a <a href="/facts/Foliose_lichen/NUDlFNnl">leaf-like</a>, membranous structure that does not swell noticeably when wet. The upper surface of the <a href="/facts/Thallus/4FbF7wmC">thallus</a> is dark olive-green to brown-black and is not hairy. The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">lobes</a> are 2 to 15 mm broad, rounded, and usually flat or partially raised, with smooth or <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">pustulate</a> surfaces adorned with elongated ridges or folds.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> </p><p>Both upper and lower <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">cortex</a> are absent in <i>Collema</i>, and the photobiont <i><a href="/facts/Nostoc/WoDSJKYR">Nostoc</a></i> forms chains of cells throughout the thallus without creating a separate <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">layer</a>. <a href="/facts/Isidia/B4h7R40q">Isidia</a> can be present or absent, while <a href="/facts/Soredia/gvyx95cL">soredia</a> are not found in this genus. The reproductive structures, known as <a href="/facts/Apothecia/aDPdgVj9">apothecia</a>, have a pale brown to red-brown <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">disc</a> that can be flat or convex. The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">thalline margin</a> is whole and sometimes displays isidia.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p><p>The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">true exciple</a> consists of cells that can be either uniformly sized or elongated. The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">epithecium</a> is indistinct and can be colourless or pigmented, while the <a href="/facts/Hymenium/ScjqHmWY">hymenium</a> is colorless and turns blue when treated with <a href="/facts/Iodine/JlfMecMf">iodine</a>. A more or less colourless <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">hypothecium</a> is also present. The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">hamathecium</a> comprises paraphyses that separate in a solution of <a href="/facts/Potassium_hydroxide/NBhPBuXc">potassium hydroxide</a> and may be unbranched or branched, often connecting near their tips, which can be club-shaped or round and exhibit a yellowish to reddish-brown hue.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> </p><p>The <a href="/facts/Ascus/kNxKp9H1">asci</a> are club-shaped (clavate) with a strongly thickened apex, and both the <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">apical dome</a> and the downwardly projecting annulus and apical cap react blue to iodine. Each ascus produces eight spores that are narrowly <a href="/facts/Ellipsoid/pe9vm0Sh">ellipsoidal</a> to spindle-shaped or nearly cylindrical with transverse <a href="/facts/Septum/lPNxGG9u">septa</a>. <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">Conidiomata</a>, or <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">pycnidia</a>, are immersed within the thallus and can be located on the margins or lamina with a pale <a href="/facts/Ostiole/z7bNQPnq">ostiole</a>. The <a href="/facts/Glossary_of_lichen_terms/K1KDWHgW">conidia</a> are rod-shaped with a slightly enlarged apex. No <a href="/facts/Lichen_product/9lDSkHvo">lichen products</a> have been detected in <i>Collema</i> using <a href="/facts/Thin-layer_chromatography/WqVGtKwT">thin-layer chromatography</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> </p> <h2 id="species">Species</h2> <p>As of April 2023<a href="https://en.wikipedia.org/w/index.php?title=Collema&action=edit">[update]</a>, <a href="/facts/Species_Fungorum/rqBKYxlD">Species Fungorum</a> (in the <a href="/facts/Catalogue_of_Life/MzzX0VRf">Catalogue of Life</a>) accepts 24 species of <i>Collema</i>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p> <ul><li><i>Collema actinoptychum</i> Nyl. (1868)<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a></li> <li><i><a href="/facts/Collema_coniophilum/lF5Cbp7m">Collema coniophilum</a></i> Goward (2009)<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> – Canada</li> <li><i><a href="/facts/Collema_flaccidum/hy5tsdU1">Collema flaccidum</a></i> (Ach.) Ach. (1810)</li> <li><i>Collema furfuraceum</i> (Schaer.) Du Rietz (1929)</li> <li><i>Collema glaucophthalmum</i> Nyl. (1858)<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a></li> <li><i>Collema glebulentum</i> (Nyl. ex Cromb.) Degel. (1952)</li> <li><i>Collema implicatum</i> Nyl. (1863)<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a></li> <li><i>Collema insulare</i> Degel. (1974)</li> <li><i>Collema japonicum</i> (Müll.Arg.) Hue (1898)</li> <li><i>Collema laeve</i> Hook.f. & Taylor (1844)</li> <li><i>Collema leptaleum</i> Tuck. (1866)<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a></li> <li><i>Collema leucocarpum</i> Hook.f. & Taylor (1844)</li> <li><i>Collema marginale</i> (Huds.) Hoffm. (1794)</li> <li><i><a href="/facts/Collema_nigrescens/kA9LDSJ3">Collema nigrescens</a></i> (Huds.) DC. (1805)</li> <li><i>Collema pulcellum</i> Ach. (1814)</li> <li><i>Collema pustulatum</i> Ach. (1814)</li> <li><i>Collema rugosum</i> Kremp. (1870)</li> <li><i>Collema ryssoleum</i> (Tuck.) A.Schneid. (1872)</li> <li><i>Collema sichuanense</i> H.J.Liu & J.C.Wei (2003))<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> – China</li> <li><i>Collema subconveniens</i> Nyl. (1888)</li> <li><i>Collema subflaccidum</i> Degel. (1974)<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a></li> <li><i>Collema subnigrescens</i> Degel. (1954)<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a></li> <li><i>Collema substipitatum</i> Zahlbr. (1930)</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"Collema". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 19 April 2023. <a href="https://www.catalogueoflife.org/data/taxon/3SBC" target="_blank">https://www.catalogueoflife.org/data/taxon/3SBC</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Dobson, F.S. (2000) Lichens, an illustrated guide to the British and Irish species. 4th edition. Richmond publishing Co., Slough, England. <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Cannon, Paul; Otálora, Mónica A.G.; Košuthová, Alica; Wedin, Mats; Aptroot, André; Coppins, Brian; Simkin, Janet (2020). "Peltigerales: Collemataceae, including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium". Revisions of British and Irish Lichens. 2: 1–38 [12]. doi:10.34885/174. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Cannon, Paul; Otálora, Mónica A.G.; Košuthová, Alica; Wedin, Mats; Aptroot, André; Coppins, Brian; Simkin, Janet (2020). "Peltigerales: Collemataceae, including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium". Revisions of British and Irish Lichens. 2: 1–38 [12]. doi:10.34885/174. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Cannon, Paul; Otálora, Mónica A.G.; Košuthová, Alica; Wedin, Mats; Aptroot, André; Coppins, Brian; Simkin, Janet (2020). "Peltigerales: Collemataceae, including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium". Revisions of British and Irish Lichens. 2: 1–38 [12]. doi:10.34885/174. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Cannon, Paul; Otálora, Mónica A.G.; Košuthová, Alica; Wedin, Mats; Aptroot, André; Coppins, Brian; Simkin, Janet (2020). "Peltigerales: Collemataceae, including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium". Revisions of British and Irish Lichens. 2: 1–38 [12]. doi:10.34885/174. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Cannon, Paul; Otálora, Mónica A.G.; Košuthová, Alica; Wedin, Mats; Aptroot, André; Coppins, Brian; Simkin, Janet (2020). "Peltigerales: Collemataceae, including the genera Blennothallia, Callome, Collema, Enchylium, Epiphloea, Lathagrium, Leptogium, Pseudoleptogium, Rostania and Scytinium". Revisions of British and Irish Lichens. 2: 1–38 [12]. doi:10.34885/174. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Collema". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 19 April 2023. <a href="https://www.catalogueoflife.org/data/taxon/3SBC" target="_blank">https://www.catalogueoflife.org/data/taxon/3SBC</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Nylander, W. (1867). "Synopsis lichenum Novae Caledoniae". Bulletin de la Société Linnéenne de Normandie. 2 (in Latin) (2): 39–140 [43]. <a href="https://www.biodiversitylibrary.org/page/9711876" target="_blank">https://www.biodiversitylibrary.org/page/9711876</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Spribille, Toby; Björk, Curtis R.; Ekman, Stefan; Elix, John A.; Goward, Trevor; Printzen, Christian; Tønsberg, Tor; Wheeler, Tim (2009). "Contributions to an epiphytic lichen flora of northwest North America: I. Eight new species from British Columbia inland rain forests". The Bryologist. 112 (1): 109–137. doi:10.1639/0007-2745-112.1.109. S2CID 84225966. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Nylander, W. (1858). "Lichenes collecti in Mexico a Fr. Müller". Flora (Regensburg) (in Latin). 41: 377–386. <a href="https://www.biodiversitylibrary.org/page/51418" target="_blank">https://www.biodiversitylibrary.org/page/51418</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Nylander, W. (1863). "Lichenographia Novogranatensis prodromus". Acta Societatis Scientiarum Fennicae (in Latin). 7 (2): 415–504. <a href="https://www.biodiversitylibrary.org/page/13599173" target="_blank">https://www.biodiversitylibrary.org/page/13599173</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Tuckerman, E. (1864). "Observations on North American and other lichens". Proceedings of the American Academy of Arts and Sciences. 6: 263–287. <a href="https://www.biodiversitylibrary.org/page/3097429" target="_blank">https://www.biodiversitylibrary.org/page/3097429</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Liu, H.J.; Wei, J.C. (2003). "Two new taxa of the lichen genus Collema from China". Mycosystema. 22 (4): 531–533. <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Degelius, G. (1974). The lichen genus Collema with special reference to the extra-European species. Symbolae Botanicae Upsalienses. Vol. 20. p. 140. <a href="/wiki/Gunnar_Degelius" target="_blank">/wiki/Gunnar_Degelius</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Degelius, G. (1954). The lichen genus Collema in Europe. Symbolae Botanicae Upsalienses. Vol. 13. p. 413. <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> </ol>