Thysananthus mollis Stephani (1912a: 798)

Sukkharak, Phiangphak, 2015, A systematic monograph of the genus Thysananthus (Lejeuneaceae, Marchantiophyta), Phytotaxa 193 (1), pp. 448-450 : 448-450

13. Thysananthus mollis Stephani (1912a: 798) . Type : PAPUA NEW GUINEA. Central : Owen Stanley Range , Summit, 1889, McGregor s.n. (holotype G!); Icon. Steph. nr. 10198.

Plants dioicous, with projecting growth, turning upwards and becoming ascending to erect, pale yellow in herbarium specimens, up to 6 cm long × 3–5 mm wide. Stems rather rigid; ventral merophyte 10–13 cell rows wide; stem in cross section orbicular, 370– 293 mm high × 270–298 µm wide, 18–20 cell layers high, composed of 38–57 epidermal cells surrounding 123–225 medullary cells, epidermal cells as large as medullary cells. Leaves imbricate, when dry suberect and convolute or laterally appressed to the stem, when moist weakly convex, apical part plane, not recurved; dorsal lobe symmetrically lanceolate, 2.2–2.8 × 0.8–1.2 mm, apex apiculate, dorsal base auriculate, auricle 27–150 × 62–150 µm, dorsal margin entire to with 3–10 teeth, the teeth consisting of 3–7 cells, being 2–3 cells wide at base and ending in a row of 1–2 cells, ventral margin plane or incurved 1/2 × leaf length, with 3–12 triangular teeth, the teeth consisting of 3–7 cells, being 2–3 cells wide at base and ending in a row of 1–2 cells; cells elongate-hexagonal with acute ends, vitta present in midportion of lobe, extending to base, 2/3 × lobe length, 18–21 cell rows wide, 27–30 cells long, marginal cells 7–10 × 7–10 µm, median vitta 27–60 × 7–10 µm, basal vitta 40–65 × 10–17 µm, trigones cordate, often coalesced, intermediate thickenings 0–2 per cell; oil bodies unknown. Lobules oblong, 0.2–0.4 × 0.1–0.2 mm, 1/10–1/8 × lobe length; appendages on surface of lobule base on both sides of stem; keel without appendage, lobule apex oblique, free margin continuing into the ventral lobe margin, apex entire to with one linear tooth, the tooth consisting of 5–6 cells, being 2–3 cells wide at base and ending in a row of 3–8 cells. Underleaves imbricate, slightly squarrose, broadly obovate to spathulate, (0.8–)1.3–2 × 0.6–1.2 mm, 2–4 × stem width, apex emarginate-lunulate, plane or plicate, margins with 12–13 triangular teeth, the teeth consisting of 3–10 cells, being 2–4 cells wide at base and ending in a row of 1–2 cells, bases cuneate, underleaf bases not adnate with leaves; cells 25–37 × 5–7 µm. Androecia terminal-intercalary on lateral branches, bracts, and bracteoles in 4–10(–23) pairs, bracts hypostatic, 0.6–2.3 × 0.3–0.8 mm, apex acute, margins entire; antheridia 2 per bract. Gynoecia with 1–2 lejeuneoid innovations forming a monochasial or diochasial pattern; lobe lanceolate, 3.1–3.4 × 0.8–1.2 mm, apex apiculate, margins in upper 2/3 with laciniate teeth 2–4 cells long at apex; lobules broadly ovate, 1/2 × lobe length, apex bifid, margin with laciniate teeth 1–4 cells long at apex; bracteoles spathulate, 2.2–2.5 × 1–1.6 mm, apex emarginate, 1/2 × bracteole length with laciniate teeth 1–4 cells long at apex, margins plane. Perianths oblong-cylindrical, 2.5–3.2 × 0.8–1.3 mm, keels in upper 1/3 with triangular teeth, the teeth consisting of 3–14 cells, being 2–5 cells wide at base and ending in a row of 1–2 cells; beak 50–65 µm (4–5 cells) in length. Figs. 25 , 26 .

Additional illustrations:— Gradstein et al. (2002, p. 76, Fig. 48).

Distribution and ecology:— Endemic to Western Melanesia; 1200–3100 m; on roots, bark of trees, twigs, fallen branches, and logs in the understory of montane forests. Fig. 5D .

Representative specimens:— Papua New Guinea. CHIMB: trail from Keglsugl to Pindaunde lakes, Gradstein 4145 ( U) ; trail from Keglsugl to Pindaunde lakes, Gradstein & Sipman 8304 (G).— EASTERN HIGHLANDS: Lipizauga Botanical Sanctuary, Thiers 3699 ( U) ; Daulo Pass, Streimann 18003 ( JE, W) .— ENGA: Mape creek, Mt. Hagen-Wapenamanda, Streimann 21646 ( JE, LAE) .— MOROBE: Ogeramnang, Clemens 5527/H–d ( JE) , ibid., 17 February 1937, Clemens s.n. ( JE) ; near Kaindi village, 23 November 1975, Inoue s.n. ( U) ; Mt. Kaindi, Gradstein 3779, 3794, 3884 ( U) , 3792 (G, GOET, U 3 packets), 3795 (G, U 2 packets), 3798 (G, U) , Gradstein & Sipman 7865, 7899 (G), Schuster 67–6319, 67–6361, 67–6364 ( JE) ; Slate-Gumi creeks divide, Streimann 33938 ( JE) , 13817 (LAE), 13921, 13924, 13927 (JE, LAE); Wagau-Malolo track, Streimann 19565 ( JE) ; Gumi divide, head of Gumi creek, Streimann 25132, 25305 ( JE) , Streimann 22786 ( LAE) ; Spreader divide, Streimann 25974, 25993, 26004, 26014 ( JE) , 26021 (JE, LAE), Streimann & Tamba 11883, 11905, 11914 ( JE, LAE) , 11957, 11970, 11980, 11992 (LAE); Bulolo-Watut divide, Streimann 25032, 25220 ( JE) , Streimann & Bellamy 13049 ( JE) , Manki Trig , Streimann & Bellamy 12971 ( LAE) ; Wau-Salamaua track, Streimann 25675 ( JE, LAE, S, W); Mt. Kaindi road, Streimann 33397 ( JE) ; Araulu logging area, Streimann 13560 ( JE) ; Kaisenik logging area, Shea 6325 ( NICH) .— SOUTHERN HIGHLANDS: Tambul-Mendi road, Streimann 26800 ( JE) ; Iaro river, Streimann 23855, 23888 ( JE, LAE) ; Lama sawmill, Streimann 26631 ( JE) .— WESTERN HIGHLANDS: Baiyer river-Ruti road, Jimi valley, Streimann 22075 ( JE) , 22239 (LAE), 22008 (JE, LAE).— WESTERN SEPIK: Amisumbil, Eliptamin, Macrosimnok 27 ( JE, LAE) .

Reported from the Solomon Islands by Gradstein et al. (2002).

Taxonomic notes:— Molecular analysis has resolved Thysananthus mollis , T. montanus and T. retusus as

44 • Phytotaxa 193 (1) © 2015 Magnolia Press

SUKKHARAK polyphyletic ( Sukkharak et al. 2011b). These species share the presence of foliar appendages on lobule bases ( Sukkharak & Gradstein 2010b). Morphologically, T. mollis is very similar to T. montanus ; differences are discussed under the latter species. In addition, T. mollis may be confused with T. fruticosus but the latter species is dendroid, autoicous, and has regularly pinnate branching, keels of all leaves with appendages, laciniate perianth teeth 2–5 cells long.

Thysananthus mollis varies in leaves and underleaves, which are sharply toothed to entire.

Figures

FIGURE 5. Distribution of Thysananthus species. A. Thysananthus amazonicus (Spruce) Schiffn. B. Thysananthus spathulistipus (Reinwardt, Blume & Nees) Lindenb. C. Thysananthus convolutus Lindenb. D. Thysananthus mollis Steph., E. Thysananthus pancheri (Steph.) Hürl. F. Thysananthus anguiformis (Hook.f. & Taylor) Taylor ex Gottsche, Lindenb. & Nees G. Thysananthus comosus Lindenb. H. Thysananthus fruticosus (Lindenb. & Gottsche) Schiffn. I. Thysananthus aculeatus Herzog. J. Thysananthus appendiculatus Steph. K. Thysananthus montanus Gradst., X.-L. He & Piippo. L. Thysananthus retusus (Reinw., Blume & Nees) B.M.Thiers & Gradst. M. Thysananthus gottschei (Jack & Steph.) Steph. N. Thysananthus ciliaris comb. nov. O. Thysananthus discretus Sukkharak & Gradst.

FIGURE 25. Thysananthus mollis Steph. A. Portion of shoot, ventral view. B. Leaves, ventral view. C. Underleaves, ventral view. D. Female bracts, ventral view: a = appendage. E. Female bracteole, ventral view. F. Perianth, dorsal view: a = appendage. G. Perianth, ventral view, a = appendage. H. Leaf apex. I. Margin cells of leaf lobe. J. Median cells of leaf lobe. K. Basal cells of leaf lobe. L–N. Leaf lobule apices. O. Cross section of stem. (All the holotype).

FIGURE 26. Thysananthus mollis Steph. A–C. Portion of shoot, ventral view. D–F. Leaves, ventral view. G–I. Underleaves, ventral view. (A, D, G from Streimann & Bellamy 13049 (JE); B, E, H from Streimann 26631 (JE); C, F, I from Gradstein 3792 (GOET)).