Ceratolejeunea J.B.Jack & Steph.

  • Authority

    Dauphin L, G. 2003. . Fl. Neotrop. Monogr. 90: 1-86. (Published by NYBG Press)

  • Family

    Lejeuneaceae

  • Scientific Name

    Ceratolejeunea J.B.Jack & Steph.

  • Type

    Type. Ceratolejeunea grandiloba Jack & Steph.

  • Synonyms

    Ceratolejeunea J.B.Jack & Steph., Ceratolejeunea grandiloba J.B.Jack & Steph.

  • Description

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    Genus Description - Plants autoicous or dioicous, usually brown, sometimes pale, yellowish or green to almost black, shiny when dry, creeping to pendent, growing in mats or turfs. Leafy shoots 0.3-2.5 mm wide, sparsely to profusely branched, irregularly pinnate to plumose. Stems in cross section 30-185 µm in diameter, with 7 epidermal (=cortical) cells, cells thin-walled, rarely thick-walled, walls to ca. 5 µm thick, and 4-30 medullary cells, cells thick-walled, walls ca. 4 µm thick, with two ventral rows of cells in surface view, and 2-3 dorsal rows, cells quadrate to rectangular, sometimes more or less transversally elongate. Branches Lejeunea-type, basal collars three-lobed, flagelliferous branches occasional, their leaves entire or toothed. Stylus unicellular, hyaline, frequently deciduous. Leaves complicate-bilobed, stem leaves imbricate to distant, usually overlapping the stem dorsally, convex or plane; leaf lobe ovate, ligulate or lanceolate, more or less symmetrical or asymmetrical, lobe margins entire, crenulate by projecting cells or toothed along the antical margin or teeth restricted to the distal half or apex, apex rounded, acute, or acuminate, incurved or plane; median leaf cells isodiametrical, elliptical, rectangular or subquadrate shaped; marginal cells quadrate to rectangular, basal leaf cells rectangular or long hexagonal, thin-walled; cell walls regularly thickened, pale brown, with or without intermediate thickenings, middle lamellae pale to dark brown, trigones almost absent to medium-sized, radiate; oil bodies smooth, finely granular to botryoidal, septate when smooth, elliptical; ocelli long-hexagonal to rounded, basal, rarely suprabasal, moniliate, seriate or dispersed in the leaf lamina, rarely present in underleaves, contiguous or isolated, with a single, homogeneous (granulose in C. grandilobal) oil body almost filling the cell lumen; lobules inflated, reduced or spherical, 0.1-0.6 the leaf lobe length, free margin involute or plane, when inflated ovate in shape, constricted before the mouth, apical tooth unicellular, frequently curved, hyaline papilla proximal, bulging. Utriculi absent, solitary or in pairs at the base of lateral branches, more or less globular or reniform. Underleaves ovate, orbicular or reniform, sometimes lanceolate, notched, bifid or entire, when bifid lobes rounded to acuminate, sinus V-shaped or U-shaped, base slightly decurrent, sometimes cordate, with rounded auricles. Vegetative reproduction by caducous leaves occasional and rarely by gemmae bom on the leaf margin, gemmae subrectangular to short elliptical, papillose. Androecia intercalary on main stems or intercalary or terminal on lateral branches, in spikes of 2-9(-14) bract pairs, bracts hypostatic, cells frequently mammillose; male bracteoles entire, notched or bifid, 1-2 per spike. Gynoecia on lateral branches or on main stems with 1-2 sterile or repeatedly fertile innovations, innovations Pycnolejeunea-type; female bracts obovate, margins entire, dentate throughout or only distally; bract lobule ovate, ovate-lanceolate, or obovate, margins entire, apex acuminate or rounded, rarely with one to several ocelli in a central basal group; bracteoles ovate, bifid to 1/4, lobes short to long acuminate, margins entire, connate at the base with the bracts. Perianth almost immersed or emergent to ca. 1/2, obconic to more or less globose, cells frequently mammillose, ocelli usually absent, rarely 1 per face; horns 4(-5) conical, triangular or bulbous, inserted laterally on the perianth body, or with 4-5 rounded keels (2 lateral, 2 postical, 0-1 dorsal). Sporophyte seta articulate, short or elongate, colorless or rarely tinged with brown, with 4 inner and 12 outer cell rows. Capsule globose, hyaline or rarely tinged with brown, splitting up to 0.7 of its length into 4 valves, the valves ovate to elliptical, erect at dehiscence, bistratose, tristratose towards the base, outer layer median cells rhomboidal, fusiform towards the base, marginal ones quadrate to short rectangular, uniformly thickened or with intermediate thickenings and more or less nodulose trigones. Elaters with a single spiral, 4-5 per valve, colorless or rarely tinged with brown, papillose. Spores long rectangular or irregularly shaped frequently with precocious germination, usually strongly papillose, papillose-tuberculate; rosettes poorly or clearly defined, with 10 to ca. 20 "teeth."

  • Discussion

    This genus has been previously cited as Ceratolejeunea (Spruce) Steph. (e.g., Bonner, 1953, 1963; Bonner et al., 1961), as Ceratolejeunea (Spruce) Schiffn. (e.g., Evans, 1920; Fulford, 1945; Schuster, 1956, 1980; Grolle, 1983; Engel, 1984), or as Ceratolejeunea Jack & Steph. (e.g., Grolle, 1983; Engel, 1989).

    According to Zijlstra (1982) and Grolle (1983), there is no valid generic name Ceratolejeunea in Stephani (1890). Grolle (1983) calls the attention to the first valid establishment of the generic name Ceratolejeunea by Jack and Stephani (1892).

    Grolle (1983) suggests rejection of Ceratolejeunea Jack & Steph. against Ceratolejeunea (Spruce) Schiffn., arguing that the type species differs from typical species described by Spruce (1884-85) in subgen. Cerato-Lejeunea. His proposal serves his opinion on nomenclatural stability (Grolle, pers. comm., 1997), considering the possibility that holostipous Ceratolejeuneas might belong in another genus. This rejection has never been formally proposed, however, and unless this is done in the future, the name Ceratolejeunea Jack & Steph. has priority. Because I consider the holostipous and schizostipous species to be congeneric, rejection of Ceratolejeunea Jack & Steph. would affect only the subgeneric names.

    Ceratolejeunea grandiloba Jack & Steph. and other members of subgen. Ceratolejeunea (=subgen. Ceratophora Schust.) are characterized by their entire underleaves, their lobule structure and bulbous horns. In other morphological (diagnostic) respects, such as pigmentation, stem structure (Bischler, 1966), presence of ocelli, utriculi, and sporophyte structure, this species group agrees with the Ceratolejeunea species with bifid underleaves. This sharing of diagnostic morphological characters suggests that both species groups should be kept in one genus. The placement of holostipous species within Ceratolejeunea and their relationship with other genera such as Neurolejeunea and Physantholejeunea has been previously discussed by several authors, including Stephani (1888), Evans (1907), Herzog (1933), and Schuster (1956, 1978, 1980). The species of Ceratolejeunea can be separated from Neurolejeunea by their proximal hyaline papillae and the presence of a single, unicellular lobule tooth. The stem morphology also helps in separating them: the ventral merophytes in species of Neurolejeunea are four or more cell rows wide (Gradstein, 1994), not two as in Ceratolejeunea and Physantholejeunea. Also the seta in Neurolejeunea has 16 outer cell rows (Gradstein, 1994), in contrast with the 12 outer cell rows in Ceratolejeunea. The lack of cell wall pigments and oil bodies in vegetative cells, the presence of a 1-2-celled apical lobular tooth, and the elongated, linear cells bordering the free lobule margin, clearly separate the monotypic Physantholejeunea from Ceratolejeunea species.

    The genus Ceratolejeunea is thus a natural, well-defined genus that stands isolated among the Lejeuneoideae. Schuster and Hattori (1954) suggested that this genus might be "more nearly allied to the Holostipae" (p. 18), because of the secondary dark pigmentation and the oil body types. The question of placement of this genus should be dealt with in a broad analysis of the family. By now it must be pointed out that not only Ceratolejeunea but also other genera within the Lejeuneoideae, such as Cheilolejeunea, Cyclolejeunea, and Lepidolejeunea, have species with entire and bifid underleaves (Gradstein, 1985). From those related genera, Ceratolejeunea differs by showing different combinations of at least two of its diagnostic characters: brown pigmentation, presence of ocelli, utriculi, and perianths with horns (see under Classification and Phylogeny).

    Distribution and Ecology: Pantropical. A ubiquitous genus in tropical and subtropical regions in America, also present in Africa, Asia, Australia, and the Pacific Islands. In the Neotropics found from southeastern United States to southern Brazil, from sea level to about 3000 m, from lowland to paramo areas, in wet and dry habitats, predominantly in forest canopies, clearings or old secondary growth areas, commonly corticolous but also occurring on leaves, rocks, logs, artificial substrates and rarely terrestrial.