Monographs Details: Marchantia paleacea Bertol.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Synonyms:Marchantia squamosa Raddi, Marchantia domingensis Lehm. & Lindenb., Marchantia tholophora Bisch., Marchantia paleacea subsp. paleacea
Description:Species Description - Thallus light or bright green, usually tinged with light red or purplish, usually 4.9-7.6 mm wide, without distinct median band on dorsal side; margins purplish or light red, rarely hyaline, cells thin-walled. Epidermal pores usually 67-92 µm diam., inner opening cruciate. Basal tissue usually with purplish or yellow sclerotic cells, with few mucilage cavities. Ventral scales in 4 rows; appendage of median scales purplish or orange, ovate (length/width ratio usually 1-1.4:1), usually 16-22 cells wide, rounded, acute or apiculate apically, margins entire, irregularly angular, crenulate, or irregularly toothed, sometimes with 1-2 conspicuous teeth toward base, marginal cells usually 23.8 times smaller than inner cells, oil cells usually numerous; laminal scales purplish or light red. Gemma cups with ciliate lobes, outer side with 1- to 2-(3)-celled papillae. Stalks of gametangiophores with conspicuous scales basally, rounded apically, without appendage. Antheridiophore stalk without band of air chambers, with 2(-4) rhizoid furrows; receptacle peltate, usually 4.3-6.5 mm diam., nearly symmetrical, usually with 6-8 shallow, rounded lobes, dorsal side without papillae. Archegoniophore stalk with 1 band of air chambers and 2(-3) rhizoid furrows; receptacle usually 4.5-6.8 mm diam., nearly symmetrical to asymmetrical, with rounded median projection on dorsal side, deeply divided into (5-)7-11 lobes, convex and costate basally, hardly broadened apically; scales of receptacle without sinuose cells apically. Involucres hyaline or purplish at margin, with ciliate lobes. Spores brown, 19-24(-28) µm diam.; spore wall pitted. Gametophytic chromosome number n = 9

Discussion:Marchantia paleacea is quite common in the Caribbean area, growing on clayey and sandy soil, on soil over rocks (limestone, sandstone, travertine), in rock crevices, on road banks, at water edges, in exposed sites or sheltered by open vegetation. It endures a short dry season and has been found most frequently in the altitudinal belt between 1000 and 2000 m, but was recorded from 500 to 3300 m.

Marchantia paleacea is easily distinguished from the other species of subgen. Chlamidium by the cruciate epidermal pores and the cupules with ciliate lobes. The ventral side of the thallus with 4 rows of scales restricted to the median portion separates it from the species of subgen. Marchantia. Two subspecies have been described: the widespread subsp, paleacea and subsp, diptera (Nees & Mont.) Inoue from Asia. All neotropical specimens belong to subsp, paleacea.

Distribution and Ecology: The species has a circumtethyan range. In Europe, it is common in the Mediterranean area to 45°N. The species has also been found in N Africa, SW Asia, the S border of the Himalayas, China, Japan, and Malaysia. Outside this main range it has been collected in Yemen, Ethiopia, S Africa, and on Reunion. In the New World, it has been recorded from 36°N in U.S.A. (Alabama, Arizona, Florida, Oklahoma, Tennessee, Texas) to 5°N. Neotropical records include Mexico (Chiapas, Chihuahua, D. F., Hidalgo, Jalisco, Mexico, Michoacan, Morelos, Nuevo Leon, Oaxaca, Puebla, Querétaro, San Luis Potosi, Veracruz), Guatemala, Honduras, Costa Rica, Bermuda (Evans, 1906), Cuba, Jamaica, Haiti, the Dominican Republic, Colombia (Cundinamarca), Venezuela (Merida). Records from farther south (Brazil, Bolivia and Chile) need confirmation.

Distribution:Cuba South America| Dominican Republic South America| Haiti South America| Veracruz Mexico North America| San Luis Potosí Mexico North America| Querétaro Mexico North America| Distrito Federal Mexico North America| Hidalgo Mexico North America| Chihuahua Mexico North America| Morelos Mexico North America| México Mexico North America| Nuevo León Mexico North America| Jalisco Mexico North America| Chiapas Mexico North America| Oaxaca Mexico North America| Michoacán Mexico North America| Puebla Mexico North America| Alajuela Costa Rica Central America| San José Costa Rica Central America| Alta Verapaz Guatemala Central America| Guatemala Guatemala Central America| Quiché Guatemala Central America| Sacatepéquez Guatemala Central America| Sololá Guatemala Central America| Comayagua Honduras Central America| Mérida Venezuela South America| Cundinamarca Colombia South America| Costa Rica South America| Saint Andrew Jamaica South America| Guantánamo Cuba South America| Santiago de Cuba Cuba South America| Oriente Cuba South America|