Andinopatagonian species of Plagiochila ( Plagiochilaceae , Marchantiophyta )

Three monotypic sections of Plagiochila are discussed, described and illustrated: Sectio Oligodontes Carl with P. lophocoleoides Mont., Sectio Flexicaules Carl with P. flexicaulis Mont. and Sectio Longiflorae Carl with P. longiflora Mont. ex Gottsche.


INTRODUCTION
Studies on the andinopatagonian species of Plagiochila were started by the author (Hässel de Menéndez 1983) in relation to the identity of specimens collected in the Chilean channels islands (Hässel de Menéndez & Solari 1985).Carl (1931: 118), has shown that a great number of sections of the genus Plagiochila are present in the valdivian and the patagonianfueguian forest area, from which also a number of endemics are known.They comprise species that are distinguished by special noteworthy characters and therefore are very interesting.Carl mentioned in particular some groups which are distinguished by their extreme and opposite forms (habitus), which have been dealt with recently by the author: Sect.Robustae Carl emend.Hässel, Sect.Equitantes (Hässel de Menéndez 2004a), Sect.Obcuneatae (Hässel de Menéndez 2004b), Sect.Hirtae Carl, Sect.Angulatae Carl (Hässel de Menéndez 2006), and Sect.Chilenses Carl (Hässel de Menéndez 2008).
Discussion.Carl (l. c.) described the parallel leaf margins, that are widened towards their bases, the few apical teeth and the wide cell reticulum of the lamina with thickened trigones.He included P. oligodon Mont.(having seen Gays specimen) and P. lophocoleoides Mont.(on a specimen from Chile collected by Hollermayer).These two names were considered by Hässel de Menéndez (1983:110) to belong to the same species.
Discussion.Carl (l. c.) pointed out the characters that define this typusas he called the section: the delicate, variously branched plants with small distant oval elongated leaves, the oblique apical portion of the cuneate leaves, and the small cells of the apical portion of the leaves.At that time specimens were only known with juvenile perianths.He included in this group Plagiochila fasciata Steph.(although describing it to have an ovoid perianth with a constricted mouth), P. filipendula Steph.and P. flexicaulis Mont.
As indicated below P. filipendula was considered a synonym of P. flexicaulis by the author (1983:102-103) and P. fasciata Steph.was included by the author (1983( :102, 104, as P. gayana Mont., 2006: 110) : 110)  Illustrations.Dugas (1929)  Description.Plants pale green, dull, 5-12 cm long, arising from creeping system distributed in the bryophyte carpet, with irregular lateral intercalary branching.Stem cylindrical yellowish green, 120-240 µm (14-15 cells) in diam., cortex 2 stratose, the cortical cells 6-9 µm in diam.with very thickened walls, the medulla cells 18-45 µm in diam., with hyaline thickened walls.Leaves obcuneate, distant, when dry longitudinally convolute, 0.60-1.20 mm long (increasing in size acroscopically when gynoecia are present), 0.30-0.80mm wide in the sub apical portion, 90-270 µm wide at the base; insertion short oblique, dorsally decurrent, with short ventral inverted U shaped, not decurrent; the lamina expanded at 45°f rom stem, cnemis short also at 45° with stem; dorsal margin straight, slightly recurved, without teeth, except for 1-several small teeth directed towards the tip of the leaf; apex of leaves truncate, straight to concave, limited by two larger teeth (the dorsal tooth larger), with several smaller intermediate teeth, ventral margin with 4-6 (-10) dissimilar teeth directed towards the apex of leaf.Lamina cells mainly isodiametric, 9-15 µm in diam., 15 µm thick with uniformly thickened walls; at the base of leaves the cells are elongated longitudinally, 30-42 µm long, the thickened walls have also intermediate nodular thickenings, the marginal cells are elongated parallel to the margin where the cuticle is 3 µm thick.Oil bodies ovoid to fusiform, 5-7 µm long, 2-2.5 µm wide, 4-8 per cell.Amphigastria small, triangular to filamentous.Dioicous.Androecia fusiform slightly curved, intercalary between normal leaves, infrequently successive, 60-100 µm wide, with 6-9 pairs of ventricose close imbricate bracts, each with 2 distal teeth and the ventral margin with 4 acute 1 cell long teeth.Gynoecia on main shoot or at tips of branches, frequently aborted and with innovations on both sides under the bracts, and repeating this structure several times on the same plant.Bracts similar to the distal leaves, obcuneate with a narrow base, to 1.83 mm long and to 1.00 mm wide with about 16 or more dissimilar triangular teeth.Perianth stipitate (not illustrated), 3.5-4.0mm high, cylindrical, above laterally flattened, the cells similar to the leaf cells, more elongated and with intermediate nodular thickenings on the cell walls; the mouth expanded to 2.5 mm wide, in the middle with 2 main triangular teeth with 10 or more cells at their base and short teeth on the remaining margin.Seta exceeding the perianth.Capsule 5-6 stratose, the outer cells with hyaline walls but with red brown radial thickenings; the inner cells with red brown semiannular thickenings.Spores red brown 15 µm in diam.covered with small baculi.Elaters curved 90-109 µm long and 12 µm wide with 1-2 helicoidal thickenings.
Plants delicate, short, arborescent; the lamina cells of leaves with trigones and thickened walls; the perianth long cylindrical laterally compressed and its opening has nearly straight long and thin bristle like teeth.
Description.Plants delicate arborescent to 5 cm long, 2.5-3.0 mm wide between leaf apices along shoot; attached to the bryophyte carpet by an irregular creeping system, irregularly branched, mainly by subfloral lateral intercalary innovations, microphyllous branches present near the base of plants.Stem straight cylindrical dorsiventrally flattened, orange coloured, 270 µm (13-14 cells) in diam., cortex 3 stratose, the cells 15 µm in diam., the thickened walls orange coloured, medulla cells 15-30 µm in diam.with thin hyaline walls.Leaves ovate, the apex rounded or truncate, 0.92-1.52mm long, 0.76-0.92mm wide, insertion oblique, dorsally not decurrent, ventrally with inverted U arch, short decurrent, cnemis short oblique; the lamina slightly ventrally oriented; dorsal margin straight, recurved, with 1-2 short distal teeth directed towards the tip of leaf; ventral margin with 11-15 straight to curved, unequal, distant teeth, these at their base 1-2 cells wide, 1-4 (-5) cells long; the teeth cells 18-24 µm long, the distal cell longer (48-66 µm) and attenuate, sometimes curved or collapsed.Lamina cells 30-45 µm long, 24-30 µm wide, 30 µm thick, with conspicuous trigones connected close to the external surfaces as thickened cell walls, the cuticle 6-9 µm thick.Oil bodies sub spherical 4-7 µm in diam.greyish, with coarse granules, (6)-8-10 per cell.Amphigastria very small and delicate.Dioicous.Male plants less branched.Androecia successive and intercalary on shoot with vegetative leaves, spindle shaped, narrower than the vegetative leafy shoot, 0.92-0.48mm wide with 3-6 pairs of contiguous to imbricate bracts; lower bracts 1.06 mm long, distal bracts 0.76 mm long, the dorsal lobe irregular to involute, the ventral portion with short teeth similar to vegetative leaves, the apex squarrose.Several gynoecia on shoot, due to successive unilateral (less frequently bilateral) subfloral innovations (under the second bract) at irregular distances.Bracts in 2 pairs, each to 2.74 mm long, 1.22 mm wide, the cells similar to leaf cells but more elongated, the teeth on both margins and more numerous and curved.Perianth 4.5-5.0mm long, and 2.2 mm wide, cylindrical at base, laterally flattened, the tip curved to one side.Perianth cells similar to the leaf cells.The opening with 2 rounded lips with bristle like, straight or curved, unequal teeth, being the middle teeth the longest, at their base 1-3 cells wide, and to 13 cells long, the lateral ones diminishing in length to only 1 cell long.Seta 16 cells in diam., exceeding the perianth.Capsule brown, pluristratose.Spores brown, 20 µm in diam.baculate.Elaters to 190 µm long with 2 helicoidal thickenings.
Discussion.Having studied the composition of the epiphytic bryophyte carpet on many trees

II. Sectio Flexicaules Carl, Ann. Bryol. Suppl. 2: 127, 1931. Lectotype species
Plagiochila lophocoleoides is present in Chile from Osorno to Peninsula Brunswick, and in Argentina from Río Negro to Tierra del Fuego.It forms loose to compact nearly flat carpets on rotten logs, wet rocks, stream banks, soil under tree ferns, wet rocks at the shore and also grows on Amomyrtus luma, .Plagiochila flexicaulis Mont.(= P. filipendula Steph.).
in the synonymy of P. heterodonta (Hook.f. & Taylor) Hook.f. & Taylor in Gottsche & al., based on one of the syntypes from Juan Fernández Is.