グロリオサ属 Gloriosa

グロリオサ属 Gloriosa

グロリオサ属はイヌサフラン科に属し、11種が知られており、アフリカ、アジアを中心に分布する（POWO）。

Gloriosa belongs to Colchicaceae and comprises 11 known species, distributed mainly in Africa and Asia (POWO).

Gloriosaには花被片が強く反り返り、花柱がほぼ直角に曲がる種（例えばGloriosa superba）と、花被片が強く反り返らず、花柱がほとんど曲がらない種（例えばGloriosa rigidifolia）があり、後者はかつてリットニア属Littoniaとして扱われたこともあったが、分子系統解析によりグロリオサ属と単系統群を形成することがわかり、現在ではグロリオサ属に統合されている (Thi et al. 2013)。

Gloriosa includes species with strongly reflexed tepals and a style bent almost at a right angle, such as Gloriosa superba, as well as species with tepals that are not strongly reflexed and a style that is scarcely bent, such as Gloriosa rigidifolia. The latter were once treated as members of the genus Littonia, but molecular phylogenetic analyses showed that they form a monophyletic group with Gloriosa. They are therefore now included in Gloriosa (Thi et al. 2013).

グロリオサのほぼ直角に曲がる雌ずい

a style of Gloriosa superba bent almost at a right angle

Gloriosa superbaの花柱は、発生過程で基部が向軸側（花の上側）へほぼ直角に屈曲する。子房では向軸側の子房室の大きさが背軸側の子房室よりも小さく、蕾の段階ですでに屈曲が認められる。柱頭は葯より突出するため、他個体の花粉を付着した送粉昆虫であるシロチョウ科のチョウ類は、訪花時にまず柱頭に接触しやすい。その結果、自家受粉の割合が低下し、他家受粉の割合が高まると考えられる（Daniels et al. 2020)。同様の雌ずいの屈曲は、Lilium martagonでも観察されている（Brantjes and Bos 1980, Corbera et al. 2018)。

In Gloriosa superba, the style becomes bent almost at a right angle toward the adaxial side, i.e. the upper side of the flower, during development. In the ovary, the adaxial locule is smaller than the abaxial locule, and the curvature is already evident at the bud stage. Because the stigma protrudes beyond the anthers, pierid butterflies carrying pollen from other individuals are likely to contact the stigma first when visiting the flower. This is thought to reduce the frequency of self-pollination and increase the frequency of cross-pollination (Daniels et al. 2020). A similar curvature of the pistil has also been observed in Lilium martagon (Brantjes and Bos 1980; Corbera et al. 2018).

グロリオサの長い口吻用の蜜腺

nectaries adapted for long proboscides in Gloriosa superba

ユリ目の共有派生形質は、花被片上に花被蜜腺を持つことである。Gloriosa superbaの蜜腺は花被片の向軸側基部にあり、チョウ類は左の写真の花弁向軸側の入口から口吻を差し込み（点線）、花被片基部にある蜜腺から吸蜜する。蜜腺への入口は、口吻の短い昆虫の吸蜜を制限し、口吻の長いチョウ類による訪花を促進していると考えられる（Daniels et al. 2020)。チョウ類が反り返った花被片の基部にある蜜腺へアプローチすると、翅の下面が葯に接触し、花粉が付着する（Daniels et al. 2020)。 A shared derived character of Liliales is the presence of tepal nectaries on the tepals. In Gloriosa superba, the nectaries are located at the adaxial base of the tepals. Butterflies insert their proboscides through the entrance on the adaxial side of the tepal shown in the photograph on the left (dotted line) and feed on nectar from the nectaries at the tepal base. The entrance to the nectary is thought to restrict nectar access by insects with short proboscides and to promote visitation by long-proboscid butterflies (Daniels et al. 2020). When butterflies approach the nectaries at the base of the reflexed tepals, the undersides of their wings come into contact with the anthers and become dusted with pollen (Daniels et al. 2020).

グロリオサの花被の色彩

Perianth coloration in Gloriosa

グロリオサの花被片に見られるオレンジ色から赤色と黄色の模様は、チョウ類に認識されやすく（Weiss 1997)、V字型の模様は蜜腺への誘引路として機能している可能性がある（Daniels et al. 2020)。 The orange-to-red and yellow pattern seen on the tepals of Gloriosa is easily recognized by butterflies (Weiss 1997), and the V-shaped pattern may function as a guide leading them to the nectaries (Daniels et al. 2020).

グロリオサの葉先の巻きひげ

Leaf-tip tendrils of Gloriosa superba

グロリオサの葉身部の先端側 (写真の黒色矢印) では表裏の区別が明瞭である。一方、巻きひげとなる葉先部（赤色矢印）は、葉身部と異なり、やや太く細長い円柱状となる。このため外形は放射相称的に見えるが、維管束は背腹性を保持している (Arber 1920)。巻きひげの先端は硬く棘状となり、他物に引っかかりやすい。葉先は、他物に接触するかどうかにかかわらず、伸長を続ける。 In the distal part of the leaf blade of Gloriosasuperba (black arrow in the photograph), the distinction between the adaxial and abaxial surfaces is clear. In contrast, the leaf-tip region that develops into a tendril (red arrow) differs from the leaf blade in becoming a somewhat thickened, slender cylindrical structure. Thus, its external morphology appears radially symmetrical, but the vascular bundles retain dorsiventrality (Arber 1920). The tip of the tendril becomes hard and spine-like, making it easy to catch on surrounding objects. The leaf tip continues to elongate regardless of whether it comes into contact with surrounding objects.

グロリオサの球茎

Corms of Gloriosa superba

イヌサフラン科の植物は、球茎または地下茎を形成する(Nordenstam 1998)。当年シュートの最初の2葉の腋芽は、翌年のシュートの茎頂となる(Nordenstam 1998, 。当年シュート自体も腋芽に由来するため、第1葉および第2葉は前葉に相当し、これら前葉の腋芽が翌年のシュートの茎頂になる。一方、前葉以外の葉の腋芽は、地上部で分枝を形成する。第1葉の腋芽は更新芽innovation budとなり、翌年に伸長する。第2葉の腋芽は予備芽reserve budとなり、通常は更新芽が損傷または枯死した場合に伸長する。ただし、環境条件や種によっては、更新芽と予備芽の両方が伸長することもある。イヌサフランとグロリオサの球茎は概観が大きく異なるが、相同な器官である。

イヌサフランでは、前年シュートの茎軸が肥大して球茎となる。球茎を掘り上げると、第1葉の葉鞘に由来する外側の皮と、第2葉の葉鞘に由来する内側の皮がある。後者は、前者よりもやや色が薄いことが多い。夏の終わりにこれらの皮を取り除くと、第1葉の腋芽である更新芽と、第2葉の腋芽である予備芽がすでに伸長していることがわかる。

グロリオサでも、イヌサフランと同様に前年シュートの茎軸が肥大する。しかし、グロリオサでは、イヌサフランとは異なり、２つの腋芽の基部が棒状に伸長する。腋芽はこの棒状部の先端に位置する。棒状部は、腋芽の基部にある前年シュートの茎軸が伸長したものであるため、表面には葉の痕跡がなく、腋芽のある先端部を除いて滑らかである。翌春になると、第1葉の腋芽である更新芽が伸長して新しいシュートを形成する。通常は第1葉および第2葉の腋芽基部だけが伸長するため、二叉の球茎となる。まれに、写真に示すように、第1葉、第2葉の腋芽に加えて、第3葉の腋芽の基部も伸長し、三叉の球茎となる場合がある。

Plants of Colchicaceae form corms or rhizomes (Nordenstam 1998). The axillary buds of the first two leaves of the current-year shoot become the shoot apices of the following year’s shoots (Nordenstam 1998). Because the current-year shoot itself is also derived from an axillary bud, the first and second leaves correspond to prophylls, and the axillary buds of these prophylls become the shoot apices of the following year’s shoots. In contrast, the axillary buds of leaves other than the prophylls form aerial branches. The axillary bud of the first leaf becomes the innovation bud and elongates in the following year. The axillary bud of the second leaf becomes the reserve bud, which usually elongates when the innovation bud is damaged or dies. However, depending on environmental conditions and species, both the innovation bud and the reserve bud may elongate. Although the corms of Colchicum and Gloriosa differ greatly in overall appearance, they are homologous organs.

In Colchicum, the stem axis of the previous year’s shoot becomes swollen to form a corm. When the corm is dug up, it has an outer tunic derived from the leaf sheath of the first leaf and an inner tunic derived from the leaf sheath of the second leaf. The latter is often slightly paler than the former. When these tunics are removed at the end of summer, it can be seen that the innovation bud, which is the axillary bud of the first leaf, and the reserve bud, which is the axillary bud of the second leaf, have already begun to elongate.

In Gloriosa, as in Colchicum, the stem axis of the previous year’s shoot becomes swollen. However, unlike in Colchicum, the bases of the two axillary buds elongate into rod-like structures in Gloriosa. The axillary buds are located at the tips of these rod-like structures. Because each rod-like structure is formed by elongation of the stem axis of the previous year’s shoot at the base of an axillary bud, its surface bears no leaf traces and is smooth except for the apical region bearing the axillary bud. In the following spring, the innovation bud, which is the axillary bud of the first leaf, elongates to form a new shoot. Usually, only the bases of the axillary buds of the first and second leaves elongate, producing a bifurcate corm. Rarely, as shown in the photograph, the base of the axillary bud of the third leaf also elongates, in addition to those of the first and second leaves, producing a trifurcate corm.

引用文献 References

POWO (2026). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; https://powo.science.kew.org/. Retrieved 3 June 2026. Distribution data from Kew Backbone Distributions (WCVP). © World Checklist of Vascular Plants, licensed under CC BY 3.0.

Brantjes, N.B.M., and Bos, J.J. (1980). Hawkmoth behavior and flower adaptation reducing self pollination in two Liliiflorae. New Phytol. 84, 139–143. https://doi.org/10.1111/J.1469-8137.1980.TB00756.X;WGROUP:STRING:PUBLICATION.

Corbera, J., Alvarez-Cros, C., and Stefanescu, C. (2018). Evidence of butterfly wing pollination in the martagon lily Lilium martagon L. Butll. Inst. Catalana Hist. Nat. 82, 117–120.

Corbera, J., Alvarez-Cros, C., and Stefanescu, C. (2018). Evidence of butterfly wing pollination in the martagon lily Lilium martagon L. Butll. Inst. Catalana Hist. Nat. 82, 117–120.

Daniels, R.J., Johnson, S.D., and Peter, C.I. (2020). Flower orientation in Gloriosa superba (Colchicaceae) promotes cross-pollination via butterfly wings. Ann. Bot. 125, 1137–1149. https://doi.org/10.1093/AOB/MCAA048.

Nordenstam, B. (1998). Colchicaceae. In The Families and Genera of Vascular Plants. Vol. III. Monocotyledons Lilianae (except Orchidaceae)., K. Kubitzki, ed. (Springer), pp. 175–185.

Thi, N. P.A., Kim, J.S., and Kim, J.H. (2013). Molecular phylogenetic relationships and implications for the circumscription of Colchicaceae (Liliales). Botanical Journal of the Linnean Society 172, 255–269. https://doi.org/10.1111/BOJ.12037;WGROUP:STRING:PUBLICATION.

Weiss, M.R. (1997). Innate colour preferences and flexible colour learning in the

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