Asterella lateralis M.Howe

  • Authority

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

  • Family

    Aytoniaceae

  • Scientific Name

    Asterella lateralis M.Howe

  • Type

    Type. Mexico. Sinaloa, foothills of Sierra Madre, Colomas, 900 m, 18 vii 1897, Rose s.n. (holotype, NY; isotypes, G-23823, NY, US).

  • Synonyms

    Fimbriaria mexicana Steph., Fimbriaria elegans (Spreng.) Lehm.

  • Description

    Species Description - Thallus flat when moist, xeromorphic, becoming strongly inrolled when dry, 1.5-5(-6) mm broad, green above, dark purple beneath and on margins; branching mostly by ventral intercalary branches. Epidermal cells with somewhat thickened walls. Epidermal pores of 3-4 concentric rings of 7-9 rows of cells. Air chambers irregular, spongy, in several layers. Ventral scales wine-red or purple, with scattered oil cells and marginal papillae, with 1-2 narrowly lanceolate appendages, not constricted at base, margin entire, apex subulate. Antheridia in a small cluster without scales on short stipitate-based ventral branches. Archegoniophore borne in apical notch on small obcordate stipitate-based ventral branch, stalk slender, 10-25 mm long, with a few whitish hanging scales at apex; carpocephalum hemispherical, with 2-4 descending lobes, covered with low tubercles to almost smooth. Involucre an entire flap. Pseudoperianth lobes (8-) 10-12, hyaline, remaining united at apex. Spores brown or red-brown (light brown according to Whittemore, in lit.), 105-135 µm diam., sculpturing similar on distal and proximal faces, distally with 4-5 large areoles across face, areoles ± smooth within, muri flat in section, alveolate, wing strongly differentiated, almost smooth. Elaters with 2 helical bands. Gametophytic chromosome number unknown.

  • Discussion

    Asterella lateralis is usually distinctive among neotropical species in having strongly xeromorphic thalli with both androecia and archegoniophores borne on short ventral branches, which are often numerous along the sides of the main thallus; the spores are also very distinctive in having a broad smooth wing without areoles (in related species the areoles on both surfaces usually extend to the outer margin of the spore wing). It can be confused with both A. echinella and A. macropoda. Asterella echinella differs in its more hygromorphic, usually flat thalli, its archegoniophores often borne on main thalli or on short to long ventral branches and its carpocephala, which have tall warts 2-3 times as long as broad; A. macropoda differs in having usually flat thalli up to 9 mm broad, acute to obtuse scale appendages, archegoniophores borne both on the main thallus and on small to large ventral branches, receptacles umbrella-shaped and spores with areoles extending to the wings. The warts on the carpocephala of A. lateralis are variable in development; in some specimens the surface is almost smooth, in others it is strongly warty but the warts are scarcely taller than broad.

    Asterella lateralis is very closely related to A. bolanderi (Austin) Underw, from California, and the 2 may be better treated as subspecies; the only consistent difference is in the spores, which in A. bolanderi have areoles extending to the equator, without a smooth wing as in A. lateralis.

    The type of Fimbriaria atrispora Steph. (G-14950), as annotated by Grolle in 1971, consists of a mixture of plants of A. lateralis (plants with antheridia on short stipitate-based ventral branches) and A. pringlei (plants with antheridia on separate terminal branch), and Stephani’s description is based on both elements. The A. lateralis element is selected above as lectotype.

    Distribution and Ecology : Asterella lateralis is a widespread species in Mexico, and it occurs in Guatemala, Costa Rica, Panama, Colombia, and Ecuador. Like A. elegans and A. echinella, it seems to prefer calcareous substrates, but is a xerophytic species, growing in drier habitats, on shady banks, limestone walls, cliffs, in Quercus and Pinus forests and at higher altitudes, from 900 to 2830 m.

  • Distribution

    San Luis Potosí Mexico North America| Distrito Federal Mexico North America| Hidalgo Mexico North America| Morelos Mexico North America| México Mexico North America| Jalisco Mexico North America| Chiapas Mexico North America| Michoacán Mexico North America| Sinaloa Mexico North America| Baja California Sur Mexico North America| Puebla Mexico North America| Nayarit Mexico North America| Chiriquí Panamá Central America| San José Costa Rica Central America| Quezaltenango Guatemala Central America| Sacatepéquez Guatemala Central America| San Marcos Guatemala Central America| Tungurahua Ecuador South America| Cauca Colombia South America|