III. A view on the Japanese Triticeae species

Triticeae species are found throughout Japan, except such as the subtropical territories of Sakishima Rettou (located south-west of the Okinawa Islands) and Ogasawara archipelago (including Iwoujima) etc. In the rest of the land, the kinds of the species distributed differ depending on the areas. It is thought that these differences are mainly determined by the climate of the islands. Agropyron yezoense, A. gmelinii and species of Elymus are not found in the area of climate where the warm-temperate evergreen forest is grown, but distributed in Hokkaido or also in Honshu inland prefecture area such as Nagano, which is relatively cool and dry through the year (see Nagano Prefecture Flora Compilation Committee 1997). On the other hand, A. tsukushiense, A. ciliare and A. humidorum are mainly in the area of the warm-temperate evergreen, and in Okinawa (Hatsushima 1971; Walker 1976), the paratropical rain forest area by Wolfe (1979). Naturalized species such as A. repens are mainly in an open land of Hokkaido and equally in Nagano prefecture (Yokouchi 1983, see Nagano Prefecture Flora Compilation Committee 1997).

1. Early study of Triticeae in Japan
Triticeae species did not appear in publications by pioneer plant collectors in Japan; C. P. Thunberg (19731828) came in 1775 and P. F. von Siebold (1796-1866) first came to Japan in 1823 (see Ohwi 1984). The appearance of Triticeae species treated by the system of Linnaean nomenclature dates back only to the years of the later nineteenth century, near 1900.

The earliest description that was on page 33 of a publication edited by Matsumura J (1905) is shown in Fig. 1. Besides two Agropyrum (Agropyron) species, those of the genus, Elymus, Hystrix identified as endemic plants, are described.

Elymus species were E. arenarius, E. dahuricus and E. sibiricus, and in Hystrix, two species were included under the name of Asprella japonica and A. sibirica var. longearistata. Although they are not native, Hordeum murinum and H. sativum are listed. Presumably H. murinum was already among the naturalized and established plants within some decades after Japan opened the country at about the middle of 1800's. Also in the list wheat and three varieties of the cultivated barley, H. sativum var. hexastichon, var. vulgare and var. distichon, which except var. distichon, came to Japan as crops probably two thousands years ago, are included. For naturalized plant species, I will discuss the cases more on later pages.

Identification of species of Elymus and Hystrix has not largely changed during last 100 years. However, identification of A. caninum was not correct by present-day classification. Species name of Agropyron went through complications and resulting confusion still remained in 1990's.

During the period after 1868 to the end of nineteenth century, besides European and American ways of study on scientific names taxonomists must have been thoughtful of those of Japanese local vernacular names and Chinese names. Matsumura J (1895) in his authentic work of this period listed Japanese species with traditional local vernacular and equally by corresponding Chinese name. Although Japanese indigenous Agropyron (Roegneria) plant was identified as Brachypodium japonicum Miq., there were three vernacular names, Natsu-no-chahikigusa, Kamoji-gusa and Kazura, and the Chinese characters to write Kamoji-gusa, as shown in Fig. 2.

2. Triticeae species seen from the etbnobotanical point of view
In spite of the abundance and general distribution of the Agropyron and Elymus species, ethno-botanically those wild Triticeae species were of little interest to the people inhabited the islands throughout the history. They seldom or never depicted in Japanese traditional pictures, nor described in documents. Clearly, people were indifferent to the plants and neglected use, although some authors who described traditional publications of encyclopedia type included them among other ornamental and horticultural plants and varieties (see Kitamura et al. 1988).

Vernacular name "Kamoji-gusa" is especially given to one species, A. tsukushiense, in present day Japan. When translated "Kamoji-gusa"in Japanese to English, a meaning of "Kamoji", is a hair piece, false hair, or a switch. Walker (1976) described A. tsukushiense, then Japanese Kamoji-gusa, gave as English "Switch grass" in his book of "Flora of Okinawa and the Southern Ryukyu Islands" as a meaning of Japanese. To this direct and precise translation I am quite agreeable. However, we must carefully consider another plant with the same common name, which is Switch grass (Panicum virgatum L.), in the United States (see Hitchcock 1950; Kucera 1961; Steyermark 1981). Nevertheless, it is interesting that both species are commonly found in the areas.

At any rate, Agropyron plants are familiar in play ground of children. That is expressed by another old name, Natsu-no-chahikigusa, and surely given rise by the image of tender and linearly shaped leaves and spikes, that is reflected also by the old name of Kazura.

3. Difference between Agropyron and Elymus
At least the species found in Japan, the genus Elymus(excluding Elymus mollis) is clearly distinguished from Agropyron in spike morphology. Hitchcock (1950) in describing the spike morphology of the genus Elymus pointed out that the rachilla distorted at base, bringing the florets more or less dorsiventral to the rachis (Fig. 3). This is characteristic to the genus Elymus and probably strongly impressed the late Dr. J. Ohwi. He pointed it out when I met him during the 1950's, and said that the distortion of rachilla is never seen in Agropyron, and then he treated it as one of the clear characters to separate the two genera throughout in his works (Ohwi 1941, 1958, 1965, 1983, 1984). In Flora of Japan, which was edited by Meyer FG and Walker EH, the English description is similar to that of Hitchcock (Ohwi 1984). Differences are sharp, in two genera growing under the same conditions. Besides the number of florets is higher in Agropyron than in Elymus species, these two characters are consistent, while spikelet number per rachis node may vary two to one and sometimes three, in Elymus.

4. Naturalized alien species distributed in wild condition of Japan
Naturalized species growing under wild conditions are included in Table 1 (see Note-7). Some species are clearly brought to Japan by human activities after contacting Western countries.

Three categories of the naturalized plant species will be considered. It could be said that there has been some different views in Japan on the sources of species growing on the Japanese archipelagos. Geologically, at least the three islands of Japan, Honshu, Kyushu and Shikoku had been connected to the Asian continent, or, separated depending on the palaeoclimate. The terms such as alien, foreign, naturalized and introduced may be more proper with reality if we are aware that the Japanese islands are separated by sea far enough so that natural distribution of wild species to the islands would not be expected.

Maekawa (1943) discussing on the plant species that are naturalized from one floral district to the different areas brought by human activities, noticed such a group that, at least in Japan, the naturalization by humans not always happen with conscious introduction. In the ancient time before writing a historical documentation, plants might have been brought to Japan in unconsciously along with the main crop species. Thus, the Triticeae species now we have in Japan could be divided into four types regarding distribution,

a: pure, endemic and indigenous,
b: prehistoric naturalized plants,
c: accompanied plants with crops,
d: naturalized wild plants (in ordinary sense).

In historical times, it would have been possible that some plants arrived accidentally with the main crops brought to Japan, and they are called accompanied plants. Naturalized plants in ordinary sense are known to include, and for what local descriptions are available are as follows:
A. repens, Hordeum murinum, Ae. cylindrica, H.brachyantherum, Ae. squarrosa, A. intermedium, etc. Except the former three species, the rest are thought to be adventitious to a local area such as sea port.

H. murinum is known to be relatively frequent in an area of Tokyo and Yokohama, where there were important main sea ports soon after Japan opened to the Western countries. Also it is thought that plants are able to be settled in areas where nature is disturbed by industrial development. Some recent local publications mention naturalized species in local flora of the prefectures of Nagano (Nagano Prefecture Flora Compilation Committee 1997), Yamagata (Yuhki 1992), and Yokohama City (Yokohama-shokubutsu-kai 2003), etc.

Three Agropyron species that are stated to be of foreign origin will be required further detail discussions, whether they are indigenous, or naturalized either prehistoric or as accompanied plants.

(1) Maekawa (1943) listed A. tsukushiense var. transiens, but it is not included in the lists by Kasahara (1968 etc.). However, Sakamoto (1959, 1961, 1978, 1984) studied an early ecotype of A. tsukushiense var. transiens and stated that such an accompanied plant line naturalized from China. However, the assumption necessitates further verification.

(2) Later Sakamoto (1978) proposed that A.humidorum is also another accompanied species. He observed sympatric distribution and relatively frequent hybridization between A. humidorum and an early ecotype of A. tsukushiense var. transiens (Sakamoto 1966), and assumed that both were naturalized from China. Osada (1989) followed Sakamoto, and stated: "S. Sakamoto says the Japanese plant may have been introduced from China anciently accompanied with Astragalus sinicus used as a green manure in the paddyfield". However, the present author does not completely agree with the assumption of being a naturalized plant, rather wishes to reserve a possibility of being an indigenous species (Muramatsu unpub).

(3) Name of A. caninum has been reported from 1905. The Japanese name for the species given is now "Ibuki-kamoji" (= switch grass, or, wheat grass of Mt. Ibuki) after the name of Mt. Ibuki (altitude 1,377 m) in Shiga prefecture. Under that name, the plant has been cited frequently without verification in books, publications and home pages. The species has been interested in Japan, because it has been said to be a remainder of plants introduced to Japan by a missionary accompanied with medical plants in the period when Japan contacted with Western countries and established a herb garden at a base area of Mt. Ibuki in 1500's (before the Tokugawa era) (see Osada 1976; Sakamoto 1982; Satake et al. 1982, etc.). However, the present author wants to argue for necessity of reconsideration and check the specimens. The reason is that the Agropyron species in the question differs from the authentic A. caninum in Europe by the present author's observation.

The A. caninum listed in the publication by Matsumura J was supposed to be comprehensive by present thought, and presumably he had tried to identify scientific name by adopting those found in European countries. In reality, A. caninum of that time merely indicated common abundant plants including such species as A. tsukushiense, etc. to which taxonomists later gave the new scientific name after 1930's.