Haplomitrium gibbsiae (Steph.) R. M. Schust, 1917

Han, Wei, Luo, Haifeng, Li, Yuqing, Li, Nanqiang, Tan, Fei, Huang, Xiangju & He, Qiang, 2025, The first report of Haplomitrium gibbsiae (Steph.) R. M. Schust. (Haplomitriaceae) from Guangxi, China, Biodiversity Data Journal 13, pp. e 155213-e 155213 : e155213-

Haplomitrium gibbsiae (Steph.) R. M. Schust, 1917

Materials

Type status: Other material. Occurrence: catalogNumber: PE 80000632 ; recordNumber: 16957; recordedBy: Q. He; occurrenceID: 7816BD46-02B2-5258-A25E-8CBD0EF2BDB5; Taxon: class: Haplomitriopsida; order: Calobryales ; family: Haplomitriaceae ; Location: continent: Asia; country: China; countryCode: China / CN; stateProvince: Guangxi Zhuang Autonomous Region; county: Rongshui Miao Autonomous County; municipality: Yongle Town; locality: Yangmei’ao ; verbatimLocality: By the roadside; verbatimElevation: 1200 m; verbatimLatitude: 25.20349 ° N; verbatimLongitude: 108.67904 ° E; Identification: identifiedBy: Q. He; Event: year: 2024; month: 5; day: 28; habitat: Growing along the roadside by the edge of the forest, rooted in thin soil and clinging to the rocky cliffs.; Record Level: language: cn

Description

The species exhibit variable morphology, with stolons arising from a prostrate, irregularly branched (Fig. 1 b-d), colourless to ivory-coloured rhizome that often appears coralloid (Fig. 2 b) and is adorned with numerous 1-2 - celled slime papillae secreting a thick mucilaginous sheath. Erect leafy shoots arise from this rhizomatous system, displaying isophyllous or rarely anisophyllous arrangement with infrequent terminal branching (Fig. 2 a-b). The leaves, bright yellow-green, translucent to opaque, rigid and brittle, are arranged in three subequal to equal ranks; lateral leaves are weakly succubously to nearly transversely inserted, often strongly undulate or crispate and widely spreading (Fig. 2 e-i). Leaf shape varies from suborbicular-ovate basally to deltoid, rhomboidal or rhomboidal-reniform distally, typically bluntly pointed or acute at the tips, widest in the basal quarter and broader than long, with bluntly pointed or acute tips and undulate to crispate margins. Unistratose, except for a 2-4 stratose basal field, they have entire margins, occasionally bearing vestigial teeth or slime papillae near reproductive zones that fade with age. Median leaf cells range from 40-65 μm wide by 45-85 μm long (Fig. 2 h-i). Leafy stems, unbranched above and nearly colourless and leafless below, with scattered, remote leaves that enlarge abruptly distally (Fig. 2 a-b). Oil bodies, hyaline and finely granular, occupy a small cell portion (Fig. 2 j).

The dioecious plant bears gametangia typically aggregated in distinct terminal rosettes, rarely scattered along the stem, with apical proliferation variably present (Fig. 1 b-d and Fig. 2 b). Male plants produce numerous antheridia (25-45 or more per androecium) in terminal receptacles, technically axillary within the cycle of male bracts, which are initially ivory-white, transitioning to cinnamon with age (Fig. 2 c and k). Female plants produce approximately 20 archegonia aggregated in a terminal receptacle ( Engel and Glenny 2008). The perichaetium varies from rhombic to subrotund or irregularly rhomboid-ovate, often sinuous-crispate, initially erect and convolute, becoming strongly spreading at maturity ( Engel and Glenny 2008). The sporophyte, protected by a perigynium bearing archegonia, bractlets and slime papillae (bractlets absent or raised to the basal one-fifth to one-third), is usually solitary, though 2-4 may develop per gametophore; the seta extends 20-25 mm above the perigynium, supporting a capsule (0.5 × 3-4 mm) that dehisces along (2-3 -) 4 (- 5) incomplete lines ( Bartholomew-Began 1991). Spores, 20-39 μm in diameter, often remain in tetrads or diads until late development, with a coarsely verrucate exine (verrucae 1.7-3.2 μm high), pale brown and adorned with irregular, roughened or tuberculate compound markings. Elaters, 7-10 μm wide × 280-520 μm long, are predominantly 2 - spiralled (occasionally 3 - spiralled), transitioning to 1 - spiralled at the tips or throughout ( Bartholomew-Began 1991, Engel and Glenny 2008).

Distribution

The newly-documented occurrence of H. gibbsiae from China, reported in this study, which, when integrated with previously established records from New Zealand ( Gibbs 1911, Campbell 1959, Schuster 1967, Allison and Child 1975), Australia ( Engel 1981), India ( Udar and Chandra 1961, Kumar and Udar 1976, Kumar and Udar 1977, Udar and Kumar 1982), Chile and Argentina ( Hässel de Menéndez 1970, Schuster 1971, Hässel de Menéndez and Solari 1975), sourced from the Tropicos and GBIF, yield a total of 93 records with valid geographic coordinates for the species. Amongst these, New Zealand accounts for the highest number of distribution records, totalling 72, followed by Chile and Australia, with 12 and seven records, respectively. This comprehensive dataset supports the development of an updated global distribution map (Fig. 3 ), which illustrates the expanded range of H. gibbsiae to include East Asia, alongside its previously documented presence in the Southern Hemisphere and the Indian subcontinent.

Ecology

In New Zealand, H. gibbsiae occupies a diverse array of habitats, ranging from moist, disturbed sites such as clay banks and swampy Sphagnum areas to alpine environments where it grows on bare, wet soil amongst small rocks, spanning elevations from sea level to at least 1280 m ( Gibbs 1911, Campbell 1959, Schuster 1967). Engel and Glenny (2008) further noted that populations in New Zealand are predominantly associated with fresh mineral soil on soil banks formed by human activities — such as road construction, track development, slips or washouts — occurring in both open sites and forested settings, particularly in areas that have experienced anthropogenic disturbance. In southern South America, the species is typically found at sea level, often in turfs on soil within shady, damp woods ( Hässel de Menéndez 1970, Schuster 1971, Hässel de Menéndez and Solari 1975). In India, H. gibbsiae is confined to the Darjeeling Region of the Eastern Himalayas, where it grows on shaded, sandy soil over rocks at elevations between 1969 and 2121 m ( Udar and Chandra 1965, Kumar and Udar 1976, Kumar and Udar 1977, Udar and Kumar 1982). The newly-discovered Chinese population of the species was found at an elevation of 1200 m, growing on thin soil over rock walls at the edge of a broad-leaved forest (Fig. 1 a, e). This habitat aligns closely with the species’ established ecological preferences, reflecting its consistent affinity for bare or thin soil conditions across both natural and disturbed environments as observed in its New Zealand distribution.

Taxon discussion

Initially described by Stephani (1917) as Calobryum gibbsiae St. from New Zealand, it was later reclassified by Schuster (1963) into the Haplomitrium . Subsequent revisions further clarified its status: Hässel de Menéndez and Solari (1975) synonymised the South American Haplomitrium chilense R. M. Schust. with the species and Bartholomew-Began (1991) subsumed several Indian taxa — Haplomitrium dentatum (D. Kumar & Udar) J. J. Engel , Haplomitrium grollei D. Kumar & Udar , Haplomitrium indicum (Udar & V. Chandra) R. M. Schust. and Haplomitrium kashyapii Udar & D. Kumar — under the same species.

According to Bartholomew-Began (1991), H. gibbsiae exhibits similarities to Haplomitrium intermedium Berrie in both symmetry and habit. However, it is distinguished by its leaves, which feature extensive multistratose basal fields (Fig. 2 i) — a characteristic that could set H. gibbsiae apart from all other Haplomitrium taxa ( Bartholomew-Began 1991). Additionally, Schuster (1963) reported that the archegonia of H. gibbsiae are typically arranged in a terminal group, with the shoot capable of continued growth in the absence of fertilisation. In contrast, that of H. intermedium may be scattered along the axis, though they are usually grouped distally. Regrettably, the specimen collected in this study was male, preventing direct observation of archegonial characteristics.

Historically, H. gibbsiae was thought to be restricted to regions such as Australasia ( Gibbs 1911, Campbell 1959, Schuster 1967, Allison and Child 1975, Engel 1981), South America ( Hässel de Menéndez 1970, Schuster 1971, Hässel de Menéndez and Solari 1975) and India ( Hässel de Menéndez 1970, Schuster 1971, Hässel de Menéndez and Solari 1975), all of which trace their geological origins to the breakup of Gondwanan ( Schuster 1972, Stech and Frey 2004). Its unexpected discovery in China, a region of East Asia shaped by the fragmentation of Laurasia, significantly expands its known geographic range (Fig. 3 ).

Notes

Due to the limited phylogenetic studies on Haplomitrium available at their time, Engel and Glenny (2008) based their treatment of the genus on adaptations and modifications of earlier works by Schuster (1967) and Schuster (1971), rather than the study by Bartholomew-Began (1991). The latter employed experimental culture techniques, along with light and electron microscopy, to investigate the ontogenetic patterns underlying the morphological features of Haplomitrium , earning widespread recognition in subsequent taxonomy ( Forrest et al. 2006, Crandall-Stotler et al. 2009, Söderström et al. 2016, WFO 2025). A key highlight of our work is the first documented record of H. gibbsiae in China, where a population was found thriving at the edge of a broad-leaved forest. Notably, the collected specimen here was male, with no female plants observed, leaving the morphological characteristics of female plants to be inferred from descriptions by Bartholomew-Began (1991) and Engel and Glenny (2008).

Figures

Figure 1. Haplomitrium gibbsiae (Steph.) R. M. Schust. in the wild. a Habitat; b-d Population; e Voucher specimen. All from HE Qiang 16957.

Figure 2. Haplomitrium gibbsiae (Steph.) R. M. Schust. a, b Plant with leaves; c Antheridia with bracts; d Transverse section of stem; e-g Leaves; h Transverse section of leaf (mid-region); i Transverse section of leaf (base); j Cell with oil body of leaves; k Antheridium. All from HE Qiang 16957.

Figure 3. The worldwide distribution map of Haplomitrium gibbsiae (Steph.) R. M. Schust. (yellow triangles, blue diamonds, orange dots, green square and red star, represent localities of New Zealand, Australia, Chile, India and China, respectively).