Acrobolbus knightii (Mitt.) Briscoe

Sukkharak, Phiangphak, 2021, An account of the genus Acrobolbus Nees (Marchantiophyta: Acrobolbaceae) in Thailand with a new record, Acrobolbus knightii (Mitt.) Briscoe, Phytotaxa 482 (3), pp. 293-296 : 295

2. Acrobolbus knightii (Mitt.) Briscoe in Briscoe, Engel, Söderström, Hagborg & von Konrat (2015: 59) ( Fig. 1 ).

Basionym:— Marsupidium knightii Mitten in Hooker (1867: 753).

Type:— NEW ZEALAND. Knight s.n. ( NY 01020890 , 01020891 )

Description:—Plants 1 leafy; prostrate, stolons lacking; yellowish brown in herbarium specimen. Stems with leaves 2.1–2.5 mm wide. Leaves alternate, succubous, plane, widely spreading, obovate-oblong, 0.8–1.4 mm long × 0.5–0.9 mm wide, symmetrically bilobed, lobes each terminating in a spinous tooth, being 2–3(–4) cells wide at base and ending in a row of 2–4 cells, sinus subtruncate, margins entire, marginal cells 25–39 × 16–32 µm, walls thin, trigones confluent, median cells 23–45 × 23–39 µm, walls thin, trigones confluent, basal cells 21–63 × 20–47 µm, walls thin, trigones nodulose; cuticle smooth; ocelli absent; oil bodies not seen. Underleaves lacking. Gynoecia and Androecia not seen.

Additional illustrations:— Hodgson (1958: p. 574, Text-Fig. I.–Fig. 5 as Marsupidium knightii ); Hässel & Solari (1972: p. 576, Láms. 2.: 7, p. 584, Láms. 3.: 9 as Tylimanthus knightii (Mitten in Hooker 1867: 753) Hässel & Solari (1972: 586)); Briscoe et al. (2017: p. 61, Fig. 2f as M. knightii ); Engel & Glenny (2019: p. 224, Fig. 62: 3; p. 231, Fig. 64).

Ecology:— Acrobolbus knightii in Thailand was found on humus-rich soil in moist shrubby forest at 1780 m.

Representative specimens:— Nakhon Si Thammarat: Khao Luang Mt. , 21 January 1966, Tagawa & Kitagawa T4972 ( BKF) .

Distribution:— Sri Lanka, China, Taiwan, Japan, Papua New Guinea, Australia, New Zealand, New Caledonia, Tahiti ( Piippo 1990), and new to Thailand.

Notes:— The most distinguishing character of Acrobolbus knightii is symmetrically bilobed leaves, in which each lobe ends in a spinous tooth.

Figures

FIGURE 1. Acrobolbus knightii. A. Portion of branch, dorsal view. B. Leaves, dorsal view. C. Marginal cells. D. Apical cells. E. Median cells. F. Basal cells. [All from Tagawa & Kitagawa T4972 (BKF)].