Archilejeunea porelloides subsp. porelloides

  • Authority

    Gradstein, S. Robbert. 1994. Lejeuneaceae: Ptychantheae, Brachiolejeuneae. Fl. Neotrop. Monogr. 62: 216. (Published by NYBG Press)

  • Family

    Lejeuneaceae

  • Scientific Name

    Archilejeunea porelloides subsp. porelloides

  • Type

    Type (Gradstein & Buskes, 1985). Venezuela. Amazonas: San Carlos del Río Negro, Spruce L44 (lectotype, MANCH, 2 colls.; isolectotype, NY, W).

  • Synonyms

    Lejeunea porelloides var. andina Spruce, Lejeunea porelloides var. longiflora Spruce, Lejeunea porelloides Spruce

  • Description

    Subspecies Description - Dioicous. Plants 4-10 cm long × 2.5-3.5 mm wide, glossy yellow brown to dark brown, ascending to erect, largely growing free from the substrate. Stems in cross section composed of 20-30 epidermal cells surrounding 28-40 similar medullary cells; ventral merophyte 6-8 cell rows wide. Leaves subimbricate, dorsal lobe ovate-oblong, ca. 1.5 × 0.9 mm, apex (narrowly) rounded, margins plane, ventral margin almost straight, forming a wide angle with the keel and not auriculate at keel junction; median cells about 30 µm in largest diam., trigones rather thick, intermediate thickenings 0-1 per cell; oil bodies not observed. Lobules subrectangular, 1/3-1/2 × lobe length, apex triangular, obtuse or acute, without discrete tooth, apical margin truncate, angle between apical margin and ventral leaf margin at junction usually less than 90°; hyaline papilla long cylindrical, positioned on the free margin proximal of the apex. Underleaves large, imbricate, rarely distant, gibbose, longer than wide to orbicular, 4 × stem width, apex rounded, plane or slightly recurved, margins not undulate. Androecia with 6-14 series of bracts. Gynoecia with 1-2 subfloral innovations, a paired innovation below and repeatedly fertile single innovations above, bracts slightly longer than vegetative leaves, lobe apex rounded to obtuse, lobules lanceolate-acuminate, about 3/4 × lobe length; bracteoles oblong, apex narrowly bifid, incision to 0.3 mm deep. Perianths with two ventral keels, sometimes one ventral keel less well developed, keels irregularly crenate-denticulate to smooth. Sporophyte as in the genus.

  • Discussion

    Archilejeunea porelloides subsp. porelloides is the largest taxon of the genus. It is easily distinguished by its large size, its distinctly elongated, ovate-oblong leaves, its underleaves which are usually longer than wide (sometimes orbicular, however) and the lack of a discrete lobule tooth. The hyaline papilla is unusually long, narrow cylindrical and stands away from the free margin proximal to the apex (Gradstein & Buskes, 1985: p. 97, fig. 2c).

    Characteristically, the apex of the lobule is usually extended distad and the angle between apical margin of lobule and ventral leaf margin is usually less than 90°. In Archilejeunea fuscescens, which has sometimes been confused with A. porelloides, the lobule apex is not extended; moreover, the apex of the lobule is always sharply toothed. Archilejeunea fuscescens is also a much smaller plant than A. porelloides, with shorter, suborbicular leaves and shorter underleaves. Moreover, the growth form and the gynoecial branching system of the two species are quite different. Archilejeunea fuscescens grows appressed to the substrate whereas A. porelloides has erect growth. Innovations in A. fuscescens are always singly whereas in A. porelloides the gynoecial branching system is made up of a pair of innovations below and repeatedly fertile single innovations above (like in Archilejeunea subgenus Dibrachiella).

  • Distribution

    Inner Amazonia (below 500 m); very common along the upstream portion of the Rio Negro. Archilejeunea porelloides subsp. porelloides grows on small trunks and twigs in lowland rain forest and in scrub.

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