Deparia x nanakuraensis K.Hori, 2020

Hori, Kiyotaka, 2020, Deparia x nanakuraensis K. Hori (Athyriaceae), a new hybrid pteridophyte from Japan, PhytoKeys 165, pp. 69-84 : 69

Deparia x nanakuraensis K.Hori hyb. nov. Figure 4

Type.

Japan. Honshu: Akita prefecture, Noshiro city, Futatsui town, Nanakura-shrine, 40°12'9.48"N, 140°15'29.82"E, alt. 23 m, deciduous forest containing Acer miyabei Maxim., Aesculus turbinata Blume, Cercidiphyllum japonicum Siebold & Zucc., Cryptomeria japonica (Thunb. ex L.f.) D.Don, Dryopteris monticola (Makino) C.Chr., and Pachysandra terminalis Siebold & Zucc., on soil, 7 Jul 2020, K. Hori 3391 (holotype: MAK467056; isotype: MBK).

Description.

Terrestrial, summer green fern. Rhizomes creeping, occasionally branched, with buds, stramineous, 15-25 × 4-7 cm, closely set with roots and persistent, densely clothed by old stipe bases, glabrous; fronds 4-6 per rhizome; stipes whitish green, 30-40 × 0.8-1.5 cm, sparsely clothed with stramineous scales at the base (1-1.5 × 0.5-1 cm), ovate; blades yellowish green adaxially, 3-pinnate-pinnatifid at the base, in the middle to upper section, 2-pinnate at the apex, 40-70 × 30-40 cm, deltoid; rachises whitish green, glabrous, sparsely clothed with stramineous scales (2-5 × 1-2 mm) and black hairs adaxially; pinnae 10-15 pairs, ascending, lanceolate, shrunken at base, alternate, petiolated (2-5 mm), sessile near the apex, lowest pinnae slightly reduced, second lowest pair usually the largest, 25-30 × 4-8 cm; pinnules, alternate on the basal and middle sections of the blade, 20-30 pairs on the basal and middle sections of the blade, 15-20 pairs on the apex of the blade, reduced distally, lanceolate, deeply serrated, vein-free, close to or reaching to the margin, 10-15 pairs in the middle lobe; sori brown, tending to appear on the abaxial surface of the middle or upper part of blades, oblong- to J-shaped, 1.5-3 mm long, on the apex or middle of veinlets, 5-10 per ultimate segment, persistent; indusium entire to serrated on margin, sporangium shrunken, spores absent.

Etymology.

The name derives from Nanakura-shrine, Futasui town, Noshiro City, Akita prefecture, northeast Japan, where Deparia x nanakuraensis was first found.

Specimens examined.

Japan. Honshu: Akita pref., Noshiro city, Futatsui town, Nanakura-shrine, 40°12'9.48"N, 140°15'29.82"E, alt. 23 m, 7 Jul 2020, K. Hori 3392, loc. cit., K. Hori 3393, loc. cit., K. Hori 3394, loc. cit., 10 Jul 2012, Y. Horii 35548 (TNS 01167830), loc. cit., Y. Horii 35549 (TNS 01167829); Aomori pref., Hachinohe city, Same town, Kamikoswa, alt. 100 m, 23 Aug 1975, coll. M. Neichi (TNS 1170337, image!); loc. cit., Kitsunetai, alt. 30m, 9 Jul 2005, coll. M. Neichi (TNS 01183638, image!); Iwate pref., Iwaizumi town, Atsuka, Matsugasawa, alt. 350 m, 18 Jul 1981, coll. M. Neichi (TNS 01161869, image!); loc. cit., Ichinoseki city, Higashiyama cho, Nagasaka, Nagahira, alt. 180 m, 22 Aug 1987, coll. M. Suzuki (TNS 932028, image!); loc. cit., Maikawa, Ohira, alt. 120 m, 22 Sep 1986, coll. M. Suzuki (TNS 9320284image!); Miyagi pref., Ishinomaki city, Mano, Uchihara, alt. 70 m, 25 May 1990, coll. K. Shogo (TNS01184195, image!); loc. cit., Sendai city, Akiu town, Baba, alt. 200 m, 15 Oct 1983, coll. K. Shogo (TNS01184194, image!); Yamagata pref., Kamiyama city, Takano, alt. 250 m, 5 Jun 1983, coll. N. Sakawa (TNS01161877, image!); Fukushima pref., Minamiaizu county, Shimosato town, Yunokami, alt. 500 m, 8 Sep 1972, coll. T. Waku (TNS01161873, image!); Saitama pref., Hannnou city, Kasasugitouge, alt. 500 m, 21 Aug 1984, coll. T. Iwata (TNS01140142, image!); loc. cit., 14 Sep 1980, coll. Y. Kobayashi (MBK0233005); loc. cit., 14 June 1981, coll. Y. Kobayashi (MBK0232983).

Distribution and ecology.

Deparia x nanakuraensis is known from the eastern and northern part of Honshu in Japan (Figure 5 ). It was observed to grow on soil under deciduous forest (Figure 6 ) or planted coniferous forest containing Cryptomeria japonica . This hybrid is endemic to Japan. In the type locality, this hybrid comprised a population of over 30 individuals with juveniles (Figure 7 ) although parents of D. viridifrons and D. pterorachis were both absent, and sporangium had no spores. However, it is expected that Deparia x nanakuraensis can reproduce young individuals from buds on its rhizome (Figure 8 ).

Conservation status.

IUCN Red List Category. Based on estimates from GeoCAT, the EOO of D. x nanakuraensis was 46,321 km2. The known AOO of D. x nanakuraensis was 44 km2. The localities correspond to less than 20 points, but I could not check the population size on each locality. Therefore, available information is inadequate to support the assessment of its extinction risk. According to the IUCN (2012) criteria, the category of Data Deficient (DD) is appropriate.

Figures

Figure 4. D. x nanakuraensis K. Hori A lower stipe scale B upper stipe scale C abaxial surface of frond and stipe D detail of adaxial pinnule E detail of abaxial pinnule, and F rhizome and base of stipes. A-F from the holotype (MAK 467056) (illustration by K. Hori).

Figure 5. Map showing the known distribution of D. x nanakuraensis in Japan. Red star indicates type locality, other circles indicate examined specimens.

Figure 6. Wild plant of D. x nanakuraensis in type locality.

Figure 7. Juvenile of D. x nanakuraensis.

Figure 8. Indefinite growth through bud (red arrow) on rhizome of D. x nanakuraensis.