Delimitation of Korean Elymus s.l
Key to the Korean tribe Triticeae including genus Elymus s.l. within subfamily Pooideae
1. Spike inflorescences with 2 or more spikelets at each node of the rachides.
2. Spikelets with 1(−2) florets, three at each node of the rachides, usually central spikelets sessile and fertile, lateral ones pedicellate and sterile, sometimes all sessile in cultivated plants ············ Hordeum 보리속
2. Spikelets with (1–)2–10 florets, 2–3 [sometimes 4–6] at each node of rachides, usually all sessile.
3. Internodes of rachides easily visible; spikelets with (1–)2–4 florets; glumes nearly vestigial or weakly developed, subulate to linear ·· Hystrix 수염개밀속
3. Internodes of rachides hardly visible; spikelets with 2–10 florets; glumes well developed, linear-lanceolate to ovate.
4. Plants usually tufts, rarely with rhizomes; distal glumes usually at least 3–7(−9) veined, generally not keeled; lemmas usually with long awned apices ··································· Elymus 갯보리속
4. Plants usually rhizomatous; glumes 1–3(−5) veined, often keeled; lemmas with unawned or shortly awned apices ·········· Leymus 갯그령속
1. Spike inflorescences with generally 1 spikelet at each node of the rachides.
5. Glumes 1 or 3–9 veined, veins converging toward apices, acute to shortly awned apices.
6. Plants perennial; spikes somewhat lax; glumes usually lanceolate to narrowly ovate and 3–9 veined; spikelets with usually 5–10 or more florets ············ ············································································ Elymus (formerly known as Agropyron in Korea) 갯보리속
6. Plants annual; spikes dense; glumes linear or subulate and 1 veined; spikelets with 2 florets ····· ·························································· Secale 호밀속
5. Glumes 3–10 veined, veins parallel or divergent, truncate, or toothed with at least 1 long awned apices.
7. Spikes somewhat dense; internodes of rachides short, not easily visible; glumes keeled and 3–10 veined ·· ································································ Triticum 밀속
7. Spikes lax; internodes of rachides are 0.6–1.2 cm long, somewhat long, easily visible; glumes not keeled and 7–10 veined ································· Aegilops 염소풀속
Taxonomic Treatments
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1. Elymus humidus (Ohwi & Sakam.) T. Osada, Illustr. Grasses of Japan 426, 738, 1989; Agropyron humidum Ohwi & Sakam., J. Jap. Bot. 39: 109, 1964; Elymus humidorus (Ohwi & Sakam.) Á. Löve, Feddes Repert. 95: 457, 1984; Campeiostachys humidora (Ohwi & Sakam.) B. R. Baum, J. L. Yang & C. Yen, J. Syst. Evol. 49: 153, 2011.—TYPE: Japan. Honshu: Koshigaya, in paddy field, 8 May 1950, J. Ohwi TNS (NSM) No. 5 (TNS, not seen) (Fig. 1).
Korean name: 둔치개밀 (Dun-chi-gae-mil).Herbs perennial. Culms tufted, erect and geniculate at bases, 40–80 cm tall; new branches and roots emerge from lower nodes of ground fallen stems after anthesis and proliferate new individuals next year asexually. Leaf sheaths glabrous. Leaf blades 7–20 × 0.3–0.7 cm, flat, scaberulous on upper surfaces and at margins, glabrous on lower surfaces; ligules ca. 0.7 mm tall, glabrous, hyaline membranous, erose margins. Inflorescences with erect and straight spikes; spikes 10–20 cm long, somewhat sparsely spikelets, sessile; internodes of rachides scaberulous, ca. 1–1.3 cm long (the lowest up to 2.5–3.3 cm). Spikelets 1 at each nodes of rachides, tightly appressed to rachides even in anthesis, 1.7–2.2(−2.5) cm long, with 4–7 florets, pale green or purple-tinged or brown. Glumes 2, widely lanceolate, subequal, 6–8 mm long, 3–5(−7) veined, apices acuminate or sometimes shortly awned, scaberulous along upper mid-veins. Lemmas lanceolate, 0.8–1.2 cm long, scaberulous along upper veins or nearly so, 5 veined, with stout and straight awned apices, awns up to 3 cm long; calluses glabrous. Paleas nearly equal to lemmas, scaberulous at margins. Anthers yellow, ca. 2.5 mm long.Flowering: May to June.Habitat: Hundreds of individuals grow along the humid grassland around the slightly raised edges of the riverside (Fig. 1E). The habitat is an area where water can easily overflow during the summer flood, and seeds are expected to be relatively easily dispersed by the flow of the water. However, this taxon is known to grow in humid places around paddy fields where there is a lot of artificial interference in Japan.Considering the characteristics of its habitat, population, and individuals, we believe it is worth being considered a domestic legally protected species. In Japan, it is treated as a vulnerable species (Environment Agency of Japan, 2000; Ibaragi et al., 2009).Distribution: Japan (Honshu, Kyushu, Shikoku) [from Ohwi and Sakamoto 1964; Ibaragi et al., 2009], Korea (Hwasungun, Jeollanam-do); Japanese populations are naturalized, according to Ohwi and Sakamoto.Specimens examined: KOREA. Jeollanam-do: Hwasun-gun, Nam-myeon, riverside in Jusan-ri, 4 Jun 2017, J.H. Kim 174208 (2 sheets, JNU); Hwasun-gun, Nam-myeon, riverside in Sasu-ri, 12 Jun 2020, C.H. Kim et al. 20200034 (5 sheets, JNU).This species was treated as a part of Elymus mayebaranus [= Agropyron mayebaranum Honda] but was published as a new species based on type specimen collected from Honshu, Japan (Ohwi [TNS (NSM) 5]) by Ohwi and Sakamoto (1964). Elymus mayebaranus is a sterile species originating from the hybridization of E. tsukushiensis var. transiens and E. humidus, and has been known to be distributed in China, Taiwan, and Japan in the past (Ohwi, 1984; Osada, 1989). However, its distribution in China and Taiwan may be inaccurate due to misidentification with E. shandongensis B. Salomon or E. tsukushiensis var. transiens, and is now treated as endemic to Japan (Chen and Zhu, 2006; Jung and Chen, 2013).According to IPNI (ipni.org), Ohwi (1965: 154) corrected the specific epithet humidum to humidorum, citing Agropyron humidorum Ohwi & Sakam., but the correction was rejected. Therefore all combinations with specific epithets “humidorum, humidorus, and humidora” are invalid.Elymus humidus (Ohwi & Sakam.) T. Osada is significantly different from other taxa, including E. dahuricus with 2 spikelets at each node of inflorescence rachides, by having 1 spikelet at each node of the rachides. In addition, this species is easily distinguished from E. ciliaris, which is remarkably different in length, because of the similar lengths of lemmas and paleas. This taxon differs from E. tsukushiensis var. transiens and most other taxa, which have curved or nodding inflorescences in the flowering period, by having always erect inflorescences and relatively thicker rachides. In addition, this species always has spikelets appressed to the rachides of the inflorescence, while E. tsukushiensis var. transiens have spikelets that spread slightly or ascend from curved rachides during the flowering period. It is also distinguished from E. gmelinii and E. ciliaris, which have strongly recurved lemma awns in the fruiting period, and E. yezoensis, which has stiff hairy calluses, by having erect lemma’s awns and smooth calluses (Table 1).Meanwhile, as Ohwi and Sakamoto (1964) reported, since E. humidus grows only around the waterside, it is distinguished from taxa growing around roadsides or grassy fields in lowlands, such as E. tsukushiensis var. transiens, and taxa in mountainous areas, such as E. yezoensis.In particular, E. humidus propagates asexually in addition to normal seed dispersal (Ohwi and Sakamoto, 1964; Osada, 1989; Ibaragi et al., 2009). This species is cut off the uppermost nodes of stems including inflorescence by wind or physical forces after maturation (Fig. 1F). It has been confirmed that new shoots and roots emerged from the nodes of the lower aerial stems that fell to the ground and propagated as new individuals the following year (Fig. 1C). Among the tribe Triticeae, E. humidus is the only species that produces individuals using this asexual method.According to Ohwi and Sakamoto (1964), it was analyzed that E. humidus had previously been introduced into Japan from China with seeds of Astragalus sinicus L. [Fabaceae] or forage crops; however, this species is not mentioned in the flora of China (Chen and Zhu, 2006). Therefore, this species is currently distributed only in Korea and Japan. As Ohwi and Sakamoto pointed out, if it is true that Japanese populations originated from other countries, and it is not distributed in geographically adjacent China or Taiwan, the possibility of it being endemic to Korea must be carefully considered.The Korean name of this species was given “Dun-chi-gae-mil” due to its habitat being found on a slightly raised edge of the riverside, known as Dun-chi in Korean. -
2. Elymus shandongensis B. Salomon, Willdenowia 19: 449, 1990; Roegneria shandongensis (B. Salomon) J. L. Yang, Y. H. Zhou & C. Yen, Guihaia 17: 22, 1997.—TYPE: China. Shandong province, Qingdao, F. C. Keng 6507 (N, not seen) (Fig. 2).
Korean name: 여름개밀 (Yeo-reum-gae-mil).Herbs perennial. Culms laxly tufted, erect or slightly geniculate at bases, 0.6–1 m tall. Leaf sheaths somewhat long hairy at margins; ligules ca. 0.6 mm long. Leaf blades 10–25 × 0.4–0.8 cm, flat or involute and scaberulous at margins, both surfaces scaberulous or nearly so. Inflorescences with early erect and slightly curved spikes at anthesis, spikes 5–20 cm long. somewhat sparsely spikelets, sessile; internodes of rachides scaberulous, ca. 1–2 cm long. Spikelets 1 at each nodes of rachides, appressed to rachides, 1.2–2.0 cm, with 5–8 florets. Glumes 2, oblong-lanceolate, subequal, proximal glumes 6–9 mm long, distal ones 7–9 mm long, 5–7(−9) veined, apices acute or shortly awned. Lemmas oblong-lanceolate, 9–10 mm long, margins membranous, awn erect, 15–30 mm; calluses smooth or nearly so. Paleas slightly small to lemmas, margins scabrous.Flowering: July to August.Habitat: A large number of individuals grow on sunny roadsides around agricultural lands where there is a lot of artificial interference (Fig. 2E), sometimes growing together with E. ciliaris and/or E. tsukushiensis var. transiens.Distribution: China (central and southeastern region) (Chen and Zhu, 2006; Jung and Chen, 2013), Korea.Specimens examined: KOREA. Chungcheongbuk-do: Jecheon-si, Susan-myeon, Wondae-ri, alt. 261 m, 25 Aug 2017, Kim J. H. 174432 (1 sheet, JNU). Jeollabuk-do: Jinan-gun, Jucheon-myeon, Unbong-ri, alt. 313 m, 14 Jul 2017, Kim J. H. 174296 (1 sheet, JNU); Kunsan-si, Napo-myeon, roadside in Jugok-ri, elev. 30 m, 17 Jul 2020, Kim, C. H. & S. S. Choi 20200035 (7 sheets, JNU). Gyeongsangnam-do: Uiryeong-gun, Daeui-myeon, Haengjeong-ri, elev. 203 m, 23 Jul 2017, Kim J. H. 174321 (1 sheet, JNU).This species was published as E. shandongensis based on the type specimen (F.C. Keng 6507, N) collected from Qingdao, Shandong province in northeastern China (Salomon, 1990), and is recognized as an endemic species that is mainly distributed in the central and southeastern regions of mainland China, including Shandong (Chen and Zhu, 2006; Jung and Chen, 2013). This species was recognized as E. mayebaranus (a hybrid species of E. tsukushiensis var. transiens and E. humidus) in China until it was published as a new species (Chen and Zhu, 2006), and is known to be distributed in North Korea (Kim, 2000). As in China, E. mayebaranus, which is known to be distributed in the northern region of Korea, is considered to be very likely to be E. shandongensis.This species is easily distinguished from taxa with 2 spikelets at each node of inflorescence rachides by having 1 spikelet at each node of rachides, similar to E. humidus, as mentioned above. Not only is this species the most similar in morphology to E. tsukushiensis var. transiens [it is treated as the same taxa as E. kamoji (Ohwi) S. L. Chen in China], but also in the characteristics of its habitats. However, E. shandongensis has spike inflorescences that curve slightly laterally in the flowering period, spikelets that always appressed to the rachides, and glumes that are usually 5–7(−9) veined, whereas E. tsukushiensis var. transiens has spikes that nod strongly toward the ground during flowering, spikelets diverging or ascending from the rachides, and glumes that are 3–5 veined. In addition, this species is also distinguished from other taxa such as E. humidus, which always has erect inflorescences, E. ciliaris and E. gmelinii, which have strongly recurved lemma awns during the fruiting period, and E. yezoensis, which has stiff hairy calluses (Table 1).The Korean name of this species was given “Yeo-reum-gae-mil” due to the fact that the flowering period is July, unlike other taxa that bloom in May, including E. ciliaris. Based on the data of our research team, the Korean and scientific names were known to the public through a press release of the National Institute of Biological Resources (NIBR) on June 21, 2019.As a result, 11 species and 7 varieties of Elymus s.l., including two unrecorded species, are known to be growing on the Korean peninsula. The following key to the species was prepared for them, however, three species and six varieties have been excluded; E. excelsus and E. nakaii, which are known to be distributed in the northern region of the Korean peninsula, E. mayebaranus of uncertain distribution in Korea, and the remaining varieties, except for E. tsukushiensis var. transiens, where the type variety is not distributed in Korea.
Key to the taxa of Korean Elymus s.l
1. Spike inflorescences with 2–3 spikelets at each node of the rachides.
1. Spike inflorescences with 1 spikelet at each node of the rachides.
3. Plants with long creeping rhizomes not forming tufts; lemmas awnless to short awned apices, awns up to ca. 0.2 cm long (up to ca. 1 cm in some varieties) · ····················································· E. repens 구주개밀
3. Plants forming tufts without long creeping rhizomes; lemmas long awned apices, 1–4 cm long (rarely a variety of E. ciliaris, 1–7 mm).
4. Lemmas with recurved awns at fruiting period.
5. Paleas distinctly shorter than lemmas (1/2–2/3), slightly oblanceolate with rounded or emarginate apices; calluses nearly smooth or glabrous; habitats mainly grassy fields or roadsides in cultivated areas or low mountains ······················· ·········································· E. ciliaris 속털개밀
5. Paleas nearly equaling or slightly shorter than lemmas (3/5–4/5), oblong with rounded apices; calluses stiff hairy; habitats woods in high mountains ··························· E. gmelinii 털개밀
4. Lemmas with always erect awns.
6. Spikes always erect; new branches and roots emerge from lower nodes of ground fallen stems and propagate new individuals asexually; habitats wet riverside edges E. humidus 둔치개밀
6. Spikes strongly nodding or slightly curved at anthesis; not propagate asexually at nodes of ground stems; habitats mostly dry roadsides or grassy fields in cultivated areas, low mountains, or woods in high mountains.
7. Calluses distinctly stiff hairy; habitats woods in high mountains ··················· E. yezoensis 자주개밀
7. Calluses smooth or nearly so; habitats roadsides or grassy fields in cultivated areas or low mountains.
8. Spikes strongly nodding at anthesis; spikelets ascending at anthesis, appressed to rachides before and after anthesis; glumes (2–)3–5(−7) veined, much smaller than lemmas; flowering in May and maturing in July ····························· ················· E. tsukushiensis var. transiens 개밀
8. Spikes slightly curved at anthesis; spikelets always appressed to rachides; glumes are 5–7(−9) veined, slightly smaller than lemmas; flowering in July and maturing in August or September ·········· E. shandongensis 여름개밀