Fissidens porrectus Mitt.

Bruggeman-Nannenga, Maria Alida, 2025, Notes on African Fissidens, including F. colliculosus Brugg. - Nann., sp. nov., F. sciophyllus subsp. capeverdensis subsp. nov. and F. pellucidus var. ripensis comb. nov., stat. nov., Cryptogamie, Bryologie 20 (3), pp. 15-33 : 28-30

Fissidens porrectus Mitt.

( Fig. 7 )

Transactions of the Linnean Society of London 23: 56, f. 17 ( Mitten 1860) . — Lectotype (designated by Slavick 1992 as holotype): Niger -exp. • Barter 1425; NY, isolectotype: PC, BM, H-BR, S.

Fissidens nitens Rehmann ex E.S.Salmon, Annals of Botany 13: 121, figs 69-74 ( Salmon 1899). — Lectotype (designated byMagill 1981, here refined with barcode): South African Republic • Rehmann, Musci austro-africani (1875-77): 289; BM[BM000871824]; isolectotypes: have been distributed as Dr. A. Rehmann, Musci austro-africani (1875-77): 289; BM[BM000871823], PC, S.

Fissidens nitens var. neglectus E.S.Salmon, Annals of Botany 13: 122, figs 75-76 ( Salmon 1899). — Lectotype (designated by Bruggeman-Nannenga 1993, here refined with barcode):

Tanzania • Lutindi; am Boden im Hochwald; Holst 3472; p.p. BM [ BM 000871825].

Fissidens mariei (Besch.) Broth., Die Natürlichen Pflanzenfamilien I (3): 358 ( Brotherus 1901); Conomitrium mariei Besch., Annales des Sciences Naturelles, Botanique, série 6, 9: 335 ( Bescherelle 1880). — Lectotype (designated here): Madagascar • Mosses of Nossi Bé; on earth; Marie s.n.; BM [ BM 001094100]; isolectotypes: PC, H-BR.

Fissidens rufolimbatus Cardot, Revue bryologique 35: 65 ( Cardot 1908). — Lectotype (designated here): Democratic Republic of the Congo [Congo belge] • Sankuru; leg. Em et M. Laurent; 1903; MNHN[ PC0106533 ]; isolectotypes: MNHN[ PC0106532 ], HBR.

Fissidens letestui P. de la Varde , Bulletin de la Société Botanique de France 74: 144, f. 41 ( Potier de la Varde 1927). — Lectotype (designated here): Gabon • Evoungoun; 9.VII.1925; Le Testu 5374; PV2221; MNHN[ PC0106481 ]; isolectotypes: MNHN[ PC0106478 , PC0106480 ] and H-BR.

Fissidens pachylomoides P. de la Varde, Revue bryologique 4 n. s.: 57, f. 1: 2a ( Potier de la Varde 1931). — Lectotype (designated here): Gabon • Idembé; Le Testu 6840; MNHN[ PC0106558 ]; isolectotypes: in PC, BR, BM.

Fissidens rufolimbatus var. torrentium P. de la Varde, Revue bryologique, n.s. 4: 59, f. 1: 2d, f ( Potier de la Varde 1931). — Lectotype: (designated here): Gabon • Chute de la Moungoungoulou; Le Testu 6866; the number in the protologue (6668) must be an orthographic error and is here corrected (ICNB art. 9.2): MNHN[ PC0106519 ]; PV3974; isolectotype: MNHN[ PC0129748 ].

Fissidens pachylomoides var. subdenticulatus P. de la Varde, Revue bryologique et lichénologique 5: 202, f. 1 ( Potier de la Varde 1932). — Lectotype (designated here): Gabon • l’Ofoué ; Eckendorff s.n.; PV4450; MNHN[ PC0106556 ]; isolectotypes: PC, NY.

Fissidens rufolimbatus var. latifolius P. de la Varde, Revue bryologique et lichénologique 8: 52 ( Potier de la Varde 1935). — Lectotype (designated by Bruggeman-Nannenga 1993 here refined with barcode): Gabon • Mont Loumanzoc; Le Testu s.n.; PV5205; MNHN[PC0106516]; isotype: MNHN[PC0106515].

Fissidens rufolimbatus var. ramosus P. de la Varde, Revue bryologique et lichénologique 8: 52 ( Potier de la Varde 1935). — Lectotype (designated by Bruggeman-Nannenga 1993, here refined with barcode): Gabon • Rocher de Nzang, Nzoumou; Le Testu s.n.; PV5443; MNHN[PC0106518]; isolectotype: MNHN[PC0106517].

Fissidens schnellii P. de la Varde, Revue bryologique et lichénologique 18: 105, f. 1 ( Potier de la Varde 1949). — Lectotype (designated here): Guinea • Ziama ; Schnell 2620; PV9954; MNHN[ PC0106522 ]; isolectotypes: BM, MNHN[ PC0106520 ; PC0106521 ].

Fissidens woodii J.Taylor & P. de la Varde, Revue bryologique et lichénologique 25: 215, f. 1 ( Potier de la Varde 1956). — Lectotype (designated by Bruggeman-Nannenga 1993 here refined with barcode): Uganda • Distr. Sese; Wood 1048; PV14077; MNHN[PC0106246]; isolectotypes: MNHN[PC0106244; PC0106245].

DIAGNOSIS (most important traits in bold). — Fissidens porrectus Mitt. is variable species. It is characterized by guttulate laminal cells ( Fig. 7M ) with smooth, firm walls. These two traits are fairly constant. Furthermore, the dorsal and apical lamina typically have a characteristic incrassate border zone ( Fig. 7B, F ) while the vaginant lamina is typically limbate (a limbidium is a border of narrow elongated cells). The last two traits, the incrassate border zone and the limbate vaginant lamina, are rather variable. The incrassate border can be (uni-) 2-4-stratose, the cells forming it are usually short and wide ( Fig. 7B, F ), less often, elongated ( Fig. 7K ). The limbidia on the vaginant laminae are usually well developed and composed of elongated cells, less often they are indistinct (without or with only a few slightly elongated cells).

B 1 C B 2 A 1 A 2 D A 3 E

Plant size and development of the limbidia and of the border zone are correlated, the largest plants having the best developed limbidia and the most elongated cells in the border zone ( Fig. 7 ). However, in several specimens this correlation is not apparent. Moreover, irregularities of the border zone are not uncommon. In spite of its confusing variability, F. porrectus is usually easily recognized by the bold printed traits. It is most likely to be confused with F. splendens Brugg.-Nann. which has similar cells and similar incrassate borders, but (contrary to F. porrectus ) the border of the vaginant lamina in this species consists entirely of isodiametric cells. Fissidens pellucidus has similar cells and cell walls, but lacks a differentiated, bistratose border zone and limbidia or has its limbidia restricted to the vaginant laminae of upper leaves of perichaetial stems. Specimens with borders of elongated cells can be mistaken for subg. Fissidens species. Species of this subgenus, however, have different sporophytes and eguttulate cells.

Fissidens porrectus strongly resembles the elimbate F. pellucidus that also has guttulate cells with firm and smooth cell walls. However, Fissidens pellucidus clearly belongs to subg. Polypodiopsis . While F. pellucidus is elimbate, F. porrectus varies from more or less elimbate to limbate on all laminae. Smooth laminal cells and limbidia on all laminae are characteristic of subgenus Fissidens Hedw. In other words, gametophytes of limbate expressions of F. porrectus ( Fig. 5N ) correspond with subg. Fissidens , but expressions with limbidia restricted to the vaginant laminae or lacking fit better in subg. Polypodiopsis . Subgenus Fissidens is further characterized by a subg. Fissidens -sporophyte, i.e. a bryoides - type peristome and 40 or more columns of exothecial cells on the theca. The sporophyte of F. porrectus is clearly a subg. Polypodiopsis- type with ± 32 columns of exothecial cells and a scariosus type peristome. This settles the species in subg. Polypodiopis. This is supported by molecular data ( Budke et al. 2023).

The incrassate border zone of the dorsal and apical lamina is one of the most conspicuous features of this species. Similar borders are widespread, but rare in the Fissidentaceae and occur in all subgenera, except subg. Fissidens . Thus the taxonomic value of this feature is limited to species level.

OTHER EXAMINED MATERIAL (Specimens used forFig. 7). — Gabon • Evoungoun; 9.VII.1925; Le Testu 5374; MNHN [ PC010648 ]; type F. lestestui .

Madagascar • Heim s.n.; MNHN [ PC0773734 A]; Niger-Exp., Barter 1425; NY, type F. porrectus .

Republic of São Tome & Principe • Principe Island, cross-country route across summit plateau of Mesa ; mixed tropical hardwood cloud forest with sedge and fern understory; on volcanic bedrock in rivulet in filtered light; 01°34’51.7”N, 07°21’04.2”E; Shevock et al. 49960 (private herbarium Bruggeman-Nannenga) .

South African Republic • Rehmann; Musci austro-africani (1875-77): 289; BM [ BM 000871824]; type F. nitens .

REMARKS

All these names have at different times and in different combinations been considered synonyms ( Bizot & Pócs 1979; Bizot et al. 1990; Bruggeman-Nannenga 1993). Thus, none of the above synonyms is truly new. The present concept embraces all previous ones.

Figures

FIG. 7. — Fissidens porrectus Mitt. variations: A, E, J, leaf apices; B, F, K, mid leaves; C, G, H, L, basal parts of leaves; D, basal part of vaginant lamina with weak intramarginal limbidium; I, border of mid dorsal lamina; M, border mid dorsal lamina and guttulate cells. A-D from type specimen F. nitens Rehmann ex E.S.Salmon (BM000871824); E-I, from type F.lestestui; MNHN[PC0106481]; J-L, from Shevock 49960; private herbarium Bruggeman-Nannenga;M, from Heim s.n.; MNHN[PC0773734A]. Scale bars: A-H, J-L, 100 μm; I, M, 50 μm.

FIG. 5. — Fissidens ferrugineus Müll.Hal.: A, perichaetial stem with dwarf male stem; B, sporophytic stem; C-D, leaf apices; E, G, mid leaves; F, basal part of leaf; H, I, vaginant laminal cells with irregular papillae at different focusing levels (H, deep, I, surface view); J-K, vaginant laminal cells with punctate papillae at different focusing levels (K, deep, J, surface view); L, cross-section of vaginant lamina showing the incrassate, unistratose limbidium; M, cross-section leaf, showing the bryoides type costa; N, detail of a theca with ± 32 columns of exothecial cells;O, detail of theca with more than 32 columns of exothecial cells. A, D, from de l’Isle s.n. (PC); B, from Pervillé 51A; BM[BM000871895]; C, E, F, L, M, from Bruggeman-Nannenga 10995 (L); G, from Pócs et al. 8670/D; EGR, L; H, I, from Pócs, Iversen, Persson & Petterson 87146/O; EGR, private herbarium Bruggeman-Nannenga;J, K, from Pócs, Mialla & Margesi 90068/G; EGR; N, from Pócs 88015/C; EGR; O, from Pócs et al. 86100/T; EGR, L. Scale bars: A, B, 1 mm; C-G, 100 μm; H-O, 50 μm.