Tortula splachnoides (Hornsch.) R.H.Zander

Larraín, Juan, Cano, María J. & Jiménez, Juan A., 2020, New bryophyte records from the Mediterranean region of Chile, Cryptogamie, Bryologie 20 (11), pp. 131-140 : 137

Tortula splachnoides (Hornsch.) R.H.Zander

SPECIMENS EXAMINED. — Chile. Región de Valparaíso: Provincia de Valparaíso, Comuna de Valparaíso, Punta Curaumilla, entre Laguna Verde y Quintay, cerca del faro, en acantilados costeros con matorral de Baccharis vernalis , Puya chilensis , Bahia ambrosioides, Eryngium paniculatum y Lobelia polyphylla , en el suelo junto al mar, 33°06’33.3”S, 71°44’10.9”W, 15 m, 29.VI.2016, J. Larraín 40299 (CONC, MUB), planicie frente al mar, entre rocas litorales, sobre tierra junto a las rocas litorales, 33°06’34.0”S, 71°44’10.6”W, 11 m, 27.VII.2016, J. Larraín 40590 (CONC, MUB); en suelo expuesto, J. Larraín 40593 (CONC), 40594 (CONC); Provincia de Petorca, Comuna de La Ligua, Los Molles, parque privado Puquén, entre matorrales de Bahia ambrosioides, Baccharis , Lithrea caustica , Pouteria splendens , Fuchsia lycioides , en suelo expuesto, 32°14’26.8”S, 71°31’06.4”W, 30 m, 31.VII.2016, J. Larraín 40596 (CONC, MUB), 40609 (CONC), 40611 (CONC), 40619B (CONC); 32°14’17.9”S, 71°31’19.4”W, 20 m, J. Larraín 40625B (CONC).

REMARKS

This taxon has cleistocarpic capsules, sometimes dehiscing by an irregular circumferential line around the middle of the urn, with large stomata on the urn base, and spores 30-35 µm in diameter, finely verrucose. The leaves are concave, with entire margins, distal laminal cells irregular-quadrate, smooth, sometimes minutely papillose, proximal laminal cells larger and hyaline, smooth, nerve variable from leaf to leaf, subpercurrent to percurrent, in cross section without guide cells, with two large ventral surface cells, and a central group of substereids disposed in 2(3) rows at midleaf, and more or less differentiated dorsally.

This taxon belongs to Tortula sect. Schizophascum (Müll.Hal.) R.H.Zander , a small section of the genus with three known taxa characterized by plants living close to the sea, leaves with costal section lacking guide cells and with stereid band more or less centrally arranged, and cleistocarpous capsules often dehiscing by irregular circumferential lines ( Zander 1993). This section has a Southern Hemispheric distribution, previously known only from South Africa, New Zealand, and Australia, and now also from southern South America. The three taxa currently accepted in the group ( Tortula splachnoides , T. willisiana R.H.Zander , and T. maritima (R.Br.bis) R.H.Zander) are all regarded as highly variable ( Magill 1981; Zander 1993), and it has been suggested these three taxa might correspond to extreme expressions of a single, variable taxon ( Magill 1981).

We studied a syntype of Dendia maritima R.Br. bis (NY936236!), collected by Robert Brown in Godley Heads, close to Christchurch, New Zealand. The plants are identical to the material from Chile regarding leaf shape, the thin cell walls, and smooth leaf cells, however spore size is a bit larger in the New Zealand plants (up to 40 µm in diameter), and the leaf costa in cross section has more strongly developed surface cells dorsally. This latter character seems to be variable judging by the illustrations in Zander (1993, cf. plate 88: 5), where the dorsal surface cells of the costa are not so strongly differentiated. In this later character, the Chilean plants are much more similar to the South African Tortula splachnoides Hornsch. as illustrated by Magill (1981: 208). The type specimen of Phascum splachnoides Hornsch. at NY (NY 1448642!, NY1448643!) correspond to a single plant in a pauper condition and a microscope slide. We could not find cross sections in the prepared slide, and the poor material did not allow further dissection. But it is evident that the leaf shape and mostly smooth leaf surface, match perfectly with the material recently found in Chile. We could not find in NY the type material of Phascum drummondii Wilson (synonym of Tortula willisiana R.H.Zander ) mentioned by Zander (1993). Although the illustrations of the type of this name provided by Wilson (1848 table I, A) do not show the leaf cross sections, the general shape of the plants and leaves suggest this name could also be a synonym of T. splachnoides and the differences be part of the variability of this interesting taxon.

In conclusion, the studied specimens and the descriptions and illustrations available clearly confirm these names refer to very closely related taxa (if not one species). However, as already Magill (1981) and Zander (1993) have stated, more material from the complete geographic range of these species are needed to be able to properly study the observed morphological variability. A deeper morphological study of Tortula sect. Schizophascum is needed. Meanwhile, we use the older name available within the group for the Chilean populations.

A complete description and illustrations of this species are given by Magill (1981).