Stenogrammitis

  • Authority

    Labiak Evangelista, Paulo H. 2011. , a new genus of grammitid ferns segregated from (Polypodiaceae). Brittonia. 63 (1): 139-149.

  • Family

    Polypodiaceae

  • Scientific Name

    Stenogrammitis

  • Description

    Description - Plants epiphytic or epipetric; rhizomes erect to short creeping, scaly, the scales reddish brown to castaneous, iridescent, deltate to lanceolate, clathrate, glabrous or bearing only an apical cilium; petioles absent to 2 cm long, dark brown, usually sparsely pubescent, the hairs hyaline or reddish simple, 1- or 2- furcate; laminae monomorphic or hemidimorphic, erect or slightly arcuate, linear, characeous to subcoriaceous, 5-10 (-20) x 0.2 - 0.5 (0.8) cm, gradually reduced or truncate at the base, when hemidimorphic, the fertile portion of the lamina less dissected than the sterile; rachises straight, visible or concealed by the laminar tissue, sparsely pubescent, the hairs hyaline or reddish, simple, 1- or 2-furcate; segments linear-deltate to deltate, 1-4(-5)x0.5- 1.5 mm, plane or slightly concave, glabrescent or with hyaline to reddish hairs similar to those of the rachis, present on veins, margins, and laminar tissue, the margin entire, plane or conduplicate, oblique or perpendicular to the rachis, usually widened at the base, decurrent basiscopically and cuneate acroscopically, apex acute to obtuse; veins simple, one per segment, concealed by the laminar tissue on the sterile portion of the lamina, usually visible on the fertile portion of the lamina beneath the sporangia, adaxially with elongate, well-marked hydathodes that lack calcareous secretions; sori basal to medial, rounded to linear- oblong, one per segment, superficial or slightly sunken and embossed on the adaxial side of the segment, sometimes partially covered by the conduplicate laminar margins, sometimes confluent and forming coenosori at the apical portion of the lamina; sporangia glabrous; spores green, trilete, papillate, 20-30 µm long.

  • Discussion

    Distribution and ecology. - Pantropical, with one species in Hawaii, one in the Islands of the South Pacific, five in Africa, and three in Madagascar. In the Neotropics, it is represented by 14 species, four occurring in Central America, six in the Antilles, two in the Andes, two in the Guyanan/Venezuelan Shields, and three in the Coastal Atlantic Rain Forest of southeastern Brazil. Species of Stenogrammitis are epiphytic or epipetric, usually occuring in cloud forests between 1000-3000m. The epipetric species usually grow on shaded, humid rocks of riverbeds, or also at higher elevations usually associated with a dense layer of mosses or lichens.

    Generic comparisons.—Stenogrammitis is readily distinguished from other grammitid genera by its linear (Fig 1, A, E, and H) laminae, often not reaching more than O.S cm in width, clathrate and iridescent rhizome scales, segments with a single and unbranched vein (Fig. 1 B, F, and L), and by having a single sorus per segment. Other genera with typically narrow laminae and a single sorus per segment are Leucotrichum, Micropolypodium, Cochlidium, and Grammitis. Cochli-dium and Grammitis are distinct from Stenogrammitis by having entire laminae (except by C. serrulatum, which is pinnatifid, and Cochlidium furcatum, which has forked laminae), and non-clathrate, orangish-rhizome scales. Micropolypodium is distinct from Stenogrammitis by having usually long setae on the stipes and laminae, and non-clathrate, orangish rhizome scales. Leucotrichum can be distinguished by the presence of laminar setae, and ciliate rhizome scales. In all four genera the veins are often 1-furcate (exceptions in Micropolypodium, Grammitis, and Cochlidium), whereas they are often simple in Stenogrammitis.

    <>Cytology and gametophytes.—Four chromosome counts have been reported for Stenogrammitis. Walker (1966) reported x=33 for Grammitis hartii [=S. hartii (Jenman) Labiak] and 132-138 univalents for Grammitis deli-tescens [=S. delitescens (Proctor) Labiak], the latter presumably a tetraploid based on x= 33. Wagner (1980), however, reported /i=32 for Grammitis limula [=S. limula (H. Christ) Labiak]. A new count, presented here for the first time, is n-33 for S. wittigiana (F6e) Labiak (Fig. 4). These four counts suggest a base number of x= 33 for the genus. The gametophytes where described by Stokey and Atkinson (19S8) for Stenogrammitis delitescens and S. myosuroides. They consist of an elongate thallus with a lobed apex, bearing 3-celled branched hairs along its margin. These branched hairs are identical to the hairs found in the sporophytes.

    Etymology.—From the Greek, stenonarrow, and Grammitis. It refers to the narrow laminae usually less than S mm wide. Nomenclatural note.—Tryon and Tryon (1982) claimed that Grammitis myosuroides (Sw.) Sw. (=,Stenogrammitis myosuroides, the type of Stenogrammitis) was the type of Xiphopteris. They considered that Desvaux (1827) inferentially lectotypified Xiphopteris when he transferred the only other species of Xiphopteris, X. serrulata (Sw.) Kaulf., to his newly described genus Micropteris. This left only A! myosuroides (Sw.) Kaulf. in Xiphopteris, and therefore it should be the lectotype. According to the Article 7.11 of Code (McNeill et al., 2006), however, lectotypification is achieved only if the type element is clearly indicated by a direct citation made by the author, using the term “type” or an equivalent. Desvaux did not do this; therefore, G. myosuroides is not the lectotype of Xiphopteris (see also example 9 of the Code, which gives a parallel example for another genus). The first typification of Xiphopteris was effectively made by Smith (1875), who explicitly designated X. serrulata (Sw.) Kaulf. (=Cochlidium serrulatum (Sw.) L. E. Bishop) as the type of this genus. Smith’s lectotypification was accepted by Copeland (1947) and Bishop (1988), who maintained Xiphopteris as a synonym of Cochlidium Kaulf.