Lecanorchis moritae Suetsugu & T.C.Hsu, 2019

Suetsugu, Kenji, Kaida, Shingo, Hsu, Tian-Chuan & Sawa, Shinichiro, 2019, Lecanorchis moritae (Orchidaceae, Vanilloideae), a new mycoheterotrophic species from Amami-Oshima Island, Japan, based on morphological and molecular data, Phytotaxa 404 (4), pp. 137-145 : 139-142

Lecanorchis moritae Suetsugu & T.C.Hsu , sp. nov. (Figs. 1,2).

Type:— JAPAN. Ryukyu Islands: Kagoshima Pref., Amami-Oshima Island , Amami City , Naze , 13 May 2018, Morita N 17-01 (holotype: TNS!, a flower in the spirit collection) .

Lecanorchis moritae is closely related and morphologically similar to L. suginoana , but differs from the latter in having a transversely elliptic lip midlobe, more triangular, entire margins of the side lobes with reddish apices, white and purple hairs on the lip and sparse unicellular papilla scattered on disc.

Terrestrial, mycoheterotrophic herbs. Roots not seen. Stem erect, 15 cm tall, yellowish brown to purplish brown, 1.5 mm in diam., unbranched with several thin, scale-like sheaths along stem. Rachis 1.0–3.0 cm long, with 5 or less densely arranged flowers. Floral bracts triangular, 3.0–5.0 mm long, apex acute, glabrous. Pedicellate ovary ascending at an acute angle, slightly contorted, inflexed, 17–26 mm long, with a ring-like excrescence below the calyculus; calyculus ca. 1.5 mm high, margin erose-denticulate. Flowers rarely fully opened, facing slightly upwards, brownish yellow to olive-brown except for lip. Dorsal sepal oblanceolate, obtuse, 15.0 × 3.2 mm. Lateral sepals obliquely oblanceolate, subacute, 15.0 × 3.5 mm. Petals obliquely oblanceolate, obtuse, 15.0 × 4.4 mm, slightly reflexed near apex. Lip trilobed, basally adnate for 2/5–1/2 of column length, 15.5 × 7.8 mm when spread out; distal 1/3 of the disc hairy; hairs white or purple, multicellular, ribbon-like, more or less branched in the distal portion, ca. 1 mm long, with scattered unicellular branchlets; posterior portion of the disc except for the base microscopically papillose; side lobes exceeding the column, about 1.5 mm high, triangular and almost entire margin or entire with 1–2 serrations on the distal margins when flattened; midlobe transversely elliptic, slightly contracted at base with an irregularly erose-dentate or erose-undulate and papillate margin, 4.6 × 4.0 mm in natural position, 4.6 × 6.2 mm when spread out. Column 10 mm long, with apical wings; wings with an incision. Anther white, 1.5 mm wide with a depression above, ventrally more or less papillose, pubescent near the slits.

[The measurements above were based on the two populations of this species known thus far and may not be entirely representative of the diversity present in the species when more specimens are found in the future.]

Distribution, phenology and conservation status: — To date, the distribution of Lecanorchis moritae appears to be restricted to two localities separated by ca. 13 km. Both populations grow under humid evergreen broadleaf forest dominated by Castanopsis sieboldii (Makino 1910: 232) Hatusima (1971: 223; Fagaceae ). Each population contains less than ten flowering plants, and currently we are not aware of any other locality where this species exists. Therefore, L. moritae should be assigned a risk of extinction of “critically endangered” [CR D1] following the categories of IUCN (2012).

Etymology:— Named for Hirokazu Morita, who collected the type specimens.

Additional specimens examined:— JAPAN. Ryukyu Islands, Kagoshima Pref., Amami-Oshima Island, Amami City , Naze , 19 May 2018, Morita N 17-17 (KYO, a flower in the spirit collection); Ryukyu Islands , Kagoshima Pref., Amami-Oshima Island , Uken Village , 10 May 2018, Morita SL 12-01 (KYO, a flower in the spirit collection) .

Taxonomic notes: — Lecanorchis moritae is morphologically similar to a group of species including L. kiusiana , L. ohwii and L. suginoana endemic to East Asia; they share two unique characters, i.e. a ring-like excrescence below the calyculus and hairs on disc and midlobe of lip with minute, unicellular papillae on their surfaces ( Tuyama 1982, Serizawa 2005). However, L. moritae clearly differs from L. kiusiana and L. ohwii because the midlobe in L. ohwii is recurved, and that of L. moritae is not. In this respect, L. moritae is most similar to L. suginoana because of the general similarities in not only gross but also floral morphology. Nonetheless, L. moritae can still be distinguished from L. suginoana by its transversely elliptic (slightly contracted at base) lip midlobe (vs. semiorbicular, not contracted at base, lip midlobe), more triangular and entire margin of sidelobes (vs. relatively rounded, and denticulate margin of sidelobes), reddish apex of lip sidelobes (vs. somewhat whitish apex of lip sidelobes), white and purple hairs (vs. white and lemon yellow hairs) on the lip and sparse unicellular papillae scattering on lip disc (vs. dense unicellular papillae scattering on lip disc).

It should be noted that L. moritae is somewhat similar to the specimens recorded as L. javanica from several localities ( Comber 1990, O’Byrne & Vermeulen 2002, Suddee et al. 2010, Ong 2018). The taxonomic identity of L. javanica has remained problematic, mainly due to incompleteness of the original description and poor condition of type specimen. The protologue of L. javanica by Blume (1856) is brief and vague: “labello gynostemium inferne amplectente, limbo subimherbi” and cannot be used to distinguish among specimens. Fortunately, we can understand the taxonomic concept that Blume referred to as L. javanica thanks to the description and line drawing later published by him ( Blume 1858), which includes enough details to identify specimens. This material indicates that the lip is simple, unlobed and sparsely hairy and slightly adnate to the column, suggesting that the specimen shows little differentiation between the lip and tepals, a condition termed peloria ( Rudall & Bateman 2002). Most later studies considered L. javanica as at least a somewhat peloric form ( Smith 1909, 1910, Ames 1911, Comber 1990). For example, Smith (1910) considered that L. triloba Smith (1908: 26) should be added to the synonymy of L. javanica on the assumption that a peloric form of L. triloba must have been described as L. javanica by Blume (1856). If Smith (1910) is correct, at species rank, L. javanica should have priority over L. subpelorica Hsu & Chung (2010: 363) , L. latens Lin & Lin (2011: 315) and L. bihuensis Lin & Wu (2012: 381) , which are all peloric forms of L. triloba with different degrees of peloria: L. subpelorica has a trilobed lip with a sparsely hairy disc; L. latens has a trilobed lip with glabrous disc, and; L. bihuensis has an entire and glabrous lip ( Hsu & Chung 2010, Lin & Lin 2011, Lin & Wu 2012). We also considered L. betongensis Suddee & Pedersen (2011: 37) to be a peloric form of L. triloba , with a similar condition to that of L. subpelorica . Considering that the holotype of L. javanica has a lip with small sidelobes and slightly hairy disc ( Ong 2018) and subpeloric “ L. triloba ” is widespread ( Hsu & Chung 2010, Suddee & Pedersen 2011), L. javanica sensu Blume (1856) may be identical with L. subpelorica and L. betongensis .

Since peloric mutants are often treated as an intraspecific variant ( Rudall & Bateman 2002), not only Smith (1910) but also Comber (1990) considered the normal condition should be considered L. javanica . However, the normal state of L. javanica sensu Comber (1990) without a pair of calli on the disc of lip is completely different from L. triloba with a pair of calli on the disc of lip ( Smith 1908). It will be somewhat difficult to precisely understand the normal condition of L. javanica since the type at Leiden is in poor condition ( Ames 1911). Therefore, given that the distant location and lack of detailed morphological data for L. javanica sensu Blume (1856) , we considered it acceptable to describe the Lecanorchis from Amami-Ohshima not as just a new locality for L. javanica but rather as a new species.

In addition, L. moritae is morphologically similar to L. pauciflora Smith (1918: 26) , judging from gross floral morphology ( Smith 1918, Smith 1922, O’Byrne & Vermeulen 2002, Ong 2018). Although Comber (1990) reduced L. pauciflora to synonymy under L. javanica , it is possible that L. javanica sensu Blume (1856) is different from L. pauciflora due to the reasons mentioned above. If not L. javanica but rather L. pauciflora is conspecific with L. moritae , L. pauciflora has priority over L. moritae . However, it would still be difficult to confirm whether L. moritae and L. pauciflora are conspecific because the key character of L. moritae , scattered papillae on the lip hairs, has not been reported in L. pauciflora . In addition, even if scattered papillae on the lip hairs can be detected, it is difficult to judge whether it is synonymous with L. moritae , L. suginoana , L. kiusiana or L. ohwi due to the minimal description and old type specimen. Since there are still too few reliable data to clarify the situation for L. pauciflora , we could not judge whether these two names should be considered synonyms.

Phylogenetic relationships: — Although Hidekazu Morita originally considered the morphologiy of L. moritae to be just an intraspecific variant of L. suginoana or a hybrid between L. suginoana and L. kiusiana , the molecular results indicate an independent specific status for L. moritae . Lecanorchis moritae is morphologically similar to L. suginoana , L. kiusiana and L. ohwii . Molecular results confirmed their close relationships since L. moritae seems to be sister to these three species ( Fig. 3 ). However, L. moritae is genetically fully differentiated from these species. The molecular divergence between L. moritae and other three species (five substitutions) is greater than the molecular divergence among L. suginoana , L. kiusiana and L. ohwii (zero to two substitutions). Therefore, both morphological (see above) and molecular data are consistent with treating L. moritae as distinct species.

In addition, our molecular analysis provides some insight into identities of closely related species. Lecanorchis suginoana was first described as the variety of L. japonica ( Tuyama 1982) , whereas Hashimoto (1990) considered it as a variety of L. kiusiana due to the similarity of general lip morphology and scattered papillae on the lip. In addition, Serizawa (2015) treated it as independent species based on its distinct column morphology, whereas Serizawa (2005) also considered L. suginoana as closer to L. kiusiana than L. japonica . Indeed, the apex of the column in L. kiusiana is significantly trifid due to partially free column wings and clinandrium ( Tuyama 1955), whereas the apex of the column in L. suginoana is truncate or obscurely trifid. We observed two unique substitutions in the ITS sequence of L. suginoana , whereas there is often no genetic divergence in this marker within intraspecific varieties, in spite of their stable morphological characteristics ( Suetsugu et al. 2018d). This is consistent with independent specific status for both species. Furthermore, we showed greater molecular divergence (six substitutions) between L. japonica and L. suginoana , confirming that L. suginoana is likely more closely related to L. kiusiana .

Unexpectedly, we did not detect any molecular divergence between L. kiusiana and L. ohwii . Recent studies have usually concluded that morphological differences support the independent specific status of L. ohwii ( Lin et al. 2016, Suetsugu et al. 2017a), considering that there are distinct differences between its putative closest relative L. kiusiana in lip and column morphology that are diagnostic characters for Lecanorchis species delimitation. In contrast, L. ohwiii has sometimes been considered a variety or a synonym of L. kiusiana ( Chung 2008, Hsu & Chung 2016) or of L. japonica ( Su 2000, Chen et al. 2009). Lecanorchis ohwii has priority over L. kiusiana if L. kiusiana and L. ohwii truly represents intraspecific variants. Therefore, although L. kiusiana var. albida Lin (1987: 147) Hsu (2016: 100) was proposed as substitute name for L. ohwii , a new combination is needed for L. kiusiana if treated as an intraspecific variant. Further study will be needed to determine if L. kiusiana and L. ohwii should be treated as synonyms.

Figures

FIGURE 3. NJ tree for Lecanorchis based on nrITS sequences. Numbers above branches are bootstrap percentages from 1000 bootstrap replicates. Numbers above the branches represent bootstrap percentages ≥50.