Plagiochasma wrightii Sull.

  • Authority

    Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)

  • Family

    Aytoniaceae

  • Scientific Name

    Plagiochasma wrightii Sull.

  • Type

    Type (Evans, 1915). U.S.A. Texas: San Marco, 1848, Wright 9 (lectotype, FH; isolectotype, NY).

  • Synonyms

    Aitonia wrightii Sull., Plagiochasma crenulatum Gottsche

  • Description

    Species Description - Thallus 3.3-4.2 mm wide, whitish, yellowish or brownish, with purplish margins; apical adventitious branches frequent. Epidermis finely granulose; epidermal cells 26-31 × 21-24 µm, with large, often nodulose trigones. Epidermal pores 27-66 per mm2, hardly raised above epidermis, 17-24 µm diam., bounded by 2(-3) concentric rings of 5-8 cells, radial walls hardly thickened. Ventral scales purplish or orange, with border of 1-2 rows of light red or hyaline, sinuose cells; appendage l(-2), triangular, apex acute, with row of (1-)2-3 cells apically, hyaline, rarely light red or purplish, widest basally, 12-17 cells wide, slightly constricted and horizontally plicate, length/width ratio 1.5-1.9:1; margins not differentiated or partly bordered by 1-2 rows of smaller cells, without papillae. Male receptacle at base of apical adventitious branch, rarely dorsal, usually reniform, with 2030 antheridia. Scales of male and female receptacles hyaline or purplish, or partly tinged with purple, acute, with 1-2 cells apically, margins with scattered papillae. Archegoniophores dorsal, stalk 0.2-4 mm long, with slightly thickened, yellow, brown or dark purplish epidermal cells. Involucres 1-4, yellow or purplish. Spores 70-82 µm diam., light or dark brown, with complete areoles on both faces, ridges tuberculate. Elaters with 2-3 helical bands. Gametophytic chromosome number unknown.

  • Discussion

    Plagiochasma wrightii is characterized by its single, hyaline, acute appendage of the scales. Plagiochasma muenchianum and P. jamaicense have similar appendages but are separated by the smooth epidermis (granulose in P. wrightii) and by the wider thalli.

    Distribution and ecology: A New World species recorded from 38°N to 17°N. It is quite common in southern U.S.A (Arizona, Colorado, Kansas, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, Texas) and Mexico (Chiapas (Bourrell, 1992), Chihuahua, Coahuila, D. F., Durango, Guerrero, Hidalgo, Mexico, Michoacán, Nuevo Leon, Oaxaca, Puebla, San Luis Potosí, Sonora, Tlaxcala, Veracruz, Zacatecas). Plagiochasma wrightii has been collected on damp sandy soil in rock crevices (limestone, sandstone, granite), from 800 m to 3000 m, in dry but warm climatic areas, in exposed habitats or rather open vegetation.

  • Distribution

    Veracruz Mexico North America| Zacatecas Mexico North America| San Luis Potosí Mexico North America| Querétaro Mexico North America| Distrito Federal Mexico North America| Hidalgo Mexico North America| Durango Mexico North America| Chihuahua Mexico North America| Coahuila Mexico North America| Tlaxcala Mexico North America| México Mexico North America| Nuevo León Mexico North America| Oaxaca Mexico North America| Michoacán Mexico North America| Guerrero Mexico North America| Sonora Mexico North America| Puebla Mexico North America|