Hydrangea acuminata subsp. australis (T. Yamaz.) Yahara, 2022

Hirota, Shun K., Yahara, Tetsukazu, Fuse, Kengo, Sato, Hiroyuki, Tagane, Shuichiro, Fujii, Shinji, Minamitani, Tadashi & Suyama, Yoshihisa, 2022, Molecular phylogeny and taxonomy of the Hydrangea serrata complex (Hydrangeaceae) in western Japan, including a new subspecies of H. acuminata from Yakushima, PhytoKeys 188, pp. 49-71 : 49

Hydrangea acuminata subsp. australis (T. Yamaz.) Yahara stat. nov.

Hydrangea serrata var. australis T. Yamaz., J. Jap. Bot. 76: 175 (2001). Type. Japan. Kagoshima Pref., Mt. Takakuma, 11 August 1942, T. Yamazaki s.n. (TI).

Hortensia serrata var. australis (T. Yamaz.) H. Ohba & S. Akiyama in Ohashi et al., Wild Fl. Jap. rev. ed. 4: 166 (2017), comb. nud.

Japanese name.

Nangoku-yama-ajisai.

Distribution and habitats.

Hydrangea acuminata subsp. australis is widely distributed at lower elevations in the Kagoshima Prefecture and the southern part of the Miyazaki Prefecture of the Kyushu Island and usually grows in disturbed places along the margins of evergreen forests or Cryptomeria plantations. JPN0908 was collected on a volcanic cliff at 1700 m elevation on Mt. Karakuni and was identified as Hydrangea acuminata subsp. australis in the MIG-seq tree (Fig. 2 ).

Note.

Hydrangea acuminata subsp. australis is distinguished from Hydrangea acuminata subsp. acuminata mainly by its larger and wider leaves often exceeding 6.2 cm wide (vs. not exceeding 6.2 cm), having more serrations along margin (22-43 vs. 9-27) and dense curled hair on the lower surface of lamina. However, JPN0908, was identified as Hydrangea acuminata subsp. australis in the MIG-seq tree, which is morphologically similar to Hydrangea acuminata subsp. acuminata in having smaller leaves, fewer serrations, and sparser pubescence on the lower surface of the leaf. This specimen might be of hybrid origin between Hydrangea acuminata subsp. australis and Hydrangea acuminata subsp. acuminata .

Representative specimens examined.

Japan. Kagoshima Pref.: Kagoshima City, 22 July 2002, with flowers, K. Maruno s.n. (KAG 083840!); Shibushi City, 4 June 2002, with fruits, K. Maruno s.n. (KAG 083882!); Aira City , 11 July 2004, K. Maruno s.n. (KAG 086731!); Kimotsuki Town , 300 m elevation, 20 July 1986, with fruits, S. Hatusima 41199 (KAG 161312!); KHydrangeahima City, 450 m elevation, 22 November 1986, with fruits, S. Hatusima 41920 (KAG 161315!); Mt. Nokubi , 700 m elevation, 12 July 1987, with flowers, S. Hatusima 42447 (KAG 161327!) .

Figures

Figure 2. Molecular phylogenetic tree reconstructed using MIG-seq. Bootstrap values are shown on the nodes, and branch lengths are shown on the internodes. Branch length represents the average number of substitutions per SNP site.