178. The Secret Story Behind the Naming of Rhododendron reticulatum

In the previous day's post, 177. History of Japanese Azaleas (Part 2), I wrote, 'Takenoshin Nakai adopted the Japanese name Kobanomitsubatsutsuji for Rhododendron reticulatum D.Don. in the 1922 publication *Trees and Shrubs of Japan, Vol. 1*, co-authored by Takenoshin Nakai and Genichi Koidzumi.' When I called a certain municipality that claimed on its website that Tomitaro Makino had coined the name Kobanomitsubatsutsuji to verify this, they could not provide a source. Therefore, I asked the Kochi Prefectural Makino Botanical Garden, along with that municipality, to tell me the first instance of its use.

However, upon checking Junichi Sugimoto's 'Species and Distribution of the Genus Rhododendron in Shizuoka Prefecture' (1976), it was noted that the Japanese name for Rhododendron reticulatum D.Don was coined by Jinzo Matsumura in 1889. Incidentally, the Latin word 'reticulatum' means 'net-like'.

Therefore, I checked Jinzo Matsumura's *Index Plantarum Japonicarum, Vol. 2, Part 2* (1912), which the Sugimoto paper cited. On pages 463-464, it was revealed that Jinzo Matsumura had assigned the Japanese name Kobanomitsubatsutsuji to Rhododendron rhombicum Miq., a synonym named later for the same species. Maximowicz had named the synonym. The Latin word 'rhombicum' means 'rhombic'.
The distribution listed—Shiobara in Shimotsuke, Futago in Sagami, Gokanosho in Higo, and Nagasaki in Hizen—is questionable. While it is slightly possible that Kobanomitsubatsutsuji is distributed in Gokanosho and Nagasaki, it does not exist in Shiobara or Futago.
It seems Tomitaro Makino published a variety of Kobanomitsubatsutsuji in 1904 and wrote a paper on the synonym Rhododendron rhombicum in 1891, but the 'Nom. Jap.' (Japanese name) field was left blank.
Thus, the one who matched the Japanese name to the scientific name of Kobanomitsubatsutsuji was Jinzo Matsumura in his 1900 *Handbook of Plant Collection*, where he had been using the name Kobanomitsubatsutsuji at a stage when only the genus name was known. However, because he did not accurately grasp that Kobanomitsubatsutsuji is distributed from the Tokai region to Kyushu, centering on the north-central Kinki region, and because he adopted a synonym due to confusion and provided no illustrations or descriptions, it is doubtful whether he is appropriate as the person who named it.

In contrast, Takenoshin Nakai provided an illustration of Kobanomitsubatsutsuji and accurately explained its characteristics and distribution as follows:
'A shrub reaching one to two ken (approx. 1.8–3.6m) in height, with short hairs on young branches. Leaves initially rotate outward, broadly ovate, initially hairy but later becoming hairless or retaining slight hairs only on the main vein of the underside. Usually has minute serrations on the edges. Flower stalks are short with brown hairs. Sepals are extremely short with brown hairs and minute glands. Corolla is about 3 cm in diameter, reddish-purple, lobes are ovate, and edges are wavy. Stamens are ten, hairless. Anthers are yellow, style is also hairless, and fruit has many brown hairs, is somewhat curved, and is about 1 cm long. Distributed in Tsushima (Mt. Homan, Mt. Ontake). Kyushu (Osumi, Mt. Kirishima; Hizen, Mt. Kurokami). Shikoku (Tosa, Mt. Yahazu). Honshu (Nagato, Kotsuki; Suo, Ogori; Bitchu, Tenjinyama in Kawakami-gun, Kurashiki; Mimasaka, Yunogo; Tajima, Hatta-mura; Aki, Miyajima; Settsu, Arima; Izumi, Makino-o; Yamashiro, Mt. Washimine). It is endemic to Japan.'
It is a shrub 1.8 to 2.6 meters tall with short hairs on young branches. The leaves spread outward, become broadly ovate, and are initially hairy, but later the hairs disappear or remain partially on the underside, and there are small serrations. The flower stalks are short and have brown hairs. The calyx is extremely short and has brown hairs and minute glands. The petals are about 3 cm in diameter and reddish-purple; the tips of the petals are ovate and wavy. There are 10 stamens without hairs, the anthers are yellow, and the style is also hairless. The fruit has many brown hairs, is somewhat curved, and is about 1 cm long. Thus, he describes the characteristics of the species as accurately as modern botanical guides.

It can be said that the distribution of Kobanomitsubatsutsuji in Honshu and Tsushima is accurate.

However, in Kyushu and Shikoku, it seems that Kirishimamitsubatsutsuji, Tosanamitsubatsutsuji, and Hizenmitsubatsutsuji, which are considered separate species today, were also included under Kobanomitsubatsutsuji.
While it is a fact that Jinzo Matsumura began using the name Kobanomitsubatsutsuji without fully identifying the species, as the staff at the Kochi Prefectural Makino Botanical Garden taught me, it can be said that Takenoshin Nakai effectively named the Japanese name Kobanomitsubatsutsuji.

References
Junichi Sugimoto, 'Species and Distribution of the Genus Rhododendron in Shizuoka Prefecture,' 1976, Nat. Hist. Tolai Dist. No. 2
Jinzo Matsumura, *Index Plantarum Japonicarum, Vol. 2, Part 2*, 1912, Maruzen
Takenoshin Nakai and Genichi Koidzumi, *Trees and Shrubs of Japan, Vol. 1*, 1922, Seibido Shoten