Description –
Glebionis segetum (syn. Chrysanthemum segetum) is a species of flowering plant in the family Asteraceae, probably native only to the eastern Mediterranean region but now naturalized in western and northern Europe as well as China and parts of North America. Common names include corn marigold and corn daisy.
Glebionis segetum is a herbaceous perennial plant growing to 80 cm tall, with spirally arranged, deeply lobed leaves 5–20 cm long. The flowers are bright yellow, produced in capitula (flowerheads) 3.5-5.5 cm in diameter, with a ring of ray florets and a centre of disc florets.
Glebionis segetum is widely naturalised outside of its native range, colonising western and central Europe with early human agriculture; it can be an invasive weed in some areas. However, it also was ranked very highly, in terms of nectar production, thus showing particular value in the role of nectar-provider for insects in a UK survey of meadow species’ production of nectar sugar and pollen. Its long blooming period helps its ranking, as it does not have few flowers with very high nectar volume per flower — coupled with a brief blooming period that completely exhausts the plant, like some top-ranked plants in nectar sugar production surveys (e.g. Bull Thistle, Cirsium vulgare). The plant strongly attracts very small butterflies and also small hoverflies such as Toxomerus marginatus.
The corn marigold appears to have been a serious weed during the 13th century in Scotland, as suggested by a law of Alexander II which states that if a farmer allows so much as a single plant to produce seed in amongst his crops, then he will be fined a sheep.
de the economically important florist’s chrysanthemum (now Chrysanthemum indicum).
The epithet segetum is a plural noun in the genitive case, meaning “of the corn[fields]”, so does not change its ending to agree with the feminine genus name.
Disgrifiad –
Planhigyn blodeuol o deulu llygad y dydd a blodyn haul ydy Melyn yr ŷd sy’n enw gwrywaidd. Mae’n perthyn i’r teulu Asteraceae. Yr enw gwyddonol (Lladin) yw Chrysanthemum segetum a’r enw Saesneg yw Corn marigold. Ceir enwau Cymraeg eraill ar y planhigyn hwn gan gynnwys Melyn yr ŷd, Aban, Gold, Gold Mair, Gold yr ŷd, Golt, Graban yr ŷd, Rhuddos, Rhuddos y Gors a Rhuddos yr ŷd. Mae’n frodorol o diroedd Môr Canoldir.
Daw’r gair “Asteraceae”, sef yr enw ar y teulu hwn, o’r gair ‘Aster’, y genws mwyaf lluosog o’r teulu – ac sy’n tarddu o’r gair Groeg ἀστήρ, sef ‘seren’.
Mae’n llysieuyn lluosflwydd a all dyfu i 80 cm, gyda’r dail (5–20 cm) wedi eu sbeiralu. Melyn llachar yw lliw’r blodau 3.5-5.5 cm mewn diametr.