Hosta longipedicellata Se.Fujii & Yahara, 2023

Yahara, Tetsukazu, Hirota, Shun K., Fujii, Seiko, Kokami, Yasushi, Fuse, Kengo, Sato, Hiroyuki, Tagane, Shuichiro & Suyama, Yoshihisa, 2023, Molecular phylogeny and taxonomy of Hosta (Asparagaceae) on Shikoku Island, Japan, including five new species, one new subspecies, and two new status assignments, PhytoKeys 235, pp. 137-187 : 137

7. Hosta longipedicellata Se.Fujii & Yahara sp. nov.

Figs 17 , 18

Diagnosis.

Hosta longipedicellata is similar to H. scabrinervia , but distinguished by its flower bracts 2-2.2 cm long, withering during flowering (compared to (2-)2.2-4.6 cm long, fresh during flowering), smaller and narrower leaf blades (compared to up to 25 × 15 cm), and the occurrence at elevations at 1700-1750 m (in contrast to at 90-550 m).

Type.

Japan. Kochi Pref.: Tosa-gun, Hongawa-mura, Mt. Tsutsujo , 1750 m elev., 1 Aug. 2006, S. Kobayashi & Y. Kurahashi FOK-077809 with flowers (holotype MBK0164413!) .

Description.

Herbs perennial. Leaves basal, spiral, long petiolate, 3 per ramet; blades ovate or oblong-ovate, 13.4-30.2 cm long, 5.4-11.8 cm, 2.2-3 time longer than wide, thinly papery, glabrous on both surfaces, base rounded to subcordate, apex acute to short acuminate, margin entire, veins in 7-10 pairs, papillose on the lower surface; petioles 15-34.3 cm long, narrowly winged, wing 0.1-0.2 cm wide, glabrous. Scape 26.5-32.5 cm long, terete. Raceme 7.6-9 cm long, 7-15-flowered; flower bracts withering in anthesis, erect, purplish light green in the upper part, light green in the lower part, oblong-lanceolate, boat-shaped, 2-2.5 cm long, 0.3-0.4 cm wide, membranous, glabrous, apex acute. Flowers not fragrant; pedicels 2.5-3.3 cm long, glabrous; perianth 4.4-6.4 cm long, funnel-form, glabrous, 6-lobed, whitish purple outside in flower buds, almost white outside and inside when flowering, midveins purplish adaxially; tube dilated from apical 2/3, lobes triangular, 1.0-1.5 cm long, 0.6-0.9 cm wide, apex obtuse. Stamens 6, slightly shorter than perianth, not exerted; filaments 4.6-4.8 cm long, upwardly curved at the distal part, white, free, glabrous, anthers purple when fresh, dark blue-grey when dried, 3 mm long. Ovary ellipsoid, 0.6-0.7 cm long, style 5.1-5.6 cm long, upwardly curved at the distal part, 1.1 cm exerted from perianths, glabrous, stigma capitate. Capsules or seeds not observed.

Phenology.

Flowering from late July to early August.

Distribution and habitat.

Japan (Kochi Prefecture). This species grows on rock cliffs at Mt. Tsutsujo, Mt. Tebako, Yasui Valley, and its vicinity in Kochi Prefecture on Shikoku Island.

Etymology.

The specific epithet is derived from the long pedicel.

Conservation status.

Using criterion D1 for IUCN Red List categories ( IUCN 2012, IUCN 2022), we recommend that this species be classified as VU (Vulnerable) because its population is estimated to be between 250 and 1000.

Japanese name.

Kamuro-giboshi (new).

Additional specimens examined.

Japan. Kochi Pref.: Tosa-gun. Hongawa-mura, Mt. Tsutsujo, 28 Jun. 2022, K. Fuse et al. JPN12637 -12639, 12647, 12654 sterile (FU!); Agawa-gun, Niyodogawa-cho , 612 m elev., 3 May 2022, Se. Fujii JPN12425 , 12426 sterile (FU!); Agawa-gun, Niyodogawa-cho, Yasui Valley , 470 m elev., 30 Jun. 2022, K. Fuse et al. JPN12674 , 12676, 12680 sterile, JPN12675 with flower buds (FU!); Agawa-gun, Niyodogawa-cho, Miyagahira, 612 m elev., Jul. 22, 2023, Se. Fujii FJW48-1, 2, 3 with flowers (MBK!); cultivated at Makino Botanical Garden, derived from Mt. Tsutsujo , 1750 m elev., T. Yahara et al. JPN3927 sterile (FU!); cultivated at Makino Botanical Garden, derived from Mt. Tebako , 1700 m elev., T. Yahara et al. JPN3936 sterile (FU!) .

Note.

The plant shown in Fig. 18 is a clone of JPN3927 that grew larger than the wild state after fertilization and was not used for the above description.

Figures

Figure 17. The type specimen of H. longipedicellata: S. Kobayashi & Y. Kurahashi FOK- 077809 (holotype MBK).

Figure 18. Plants of H. longipedicellata cultivated at the Makino Botanical Garden (photos taken on 3 Jun. 2022 by Se. Fujii). Scale bars: 10 cm (A); 1 cm (B).