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''Senecio squalidus'', known as Oxford ragwort, is a member of the ''Senecio'' genus in the daisy family Asteraceae. It is a yellow-flowered herbaceous plant, native to mountainous, rocky or volcanic areas, that has managed to find other homes on man-made and natural piles of rocks, war-ruined neighborhoods and even on stone walls. These habitats resemble its well drained natural rocky homeland. The plants have spread via the wind, rail and the activities of botanists. The travels and discriminative tendencies regarding propagation of this short-lived perennial, biennial, or winter annual make it a good subject for studies of the evolution and ecology of flowering plants. ==Description== Like all members of the Asteraceae family, ''Senecio squalidus'' has a flower head known as a Capitulum. What look like single flowers are actually a cluster of florets, with each petal or corolla being a flower, or floret, possessing its own stamen and capable of producing the specialized seed of the family Asteraceae, the parachute-like achene. Oxford Ragwort is a short-lived perennial, a biennial, or a winter annual and grows in a branched straggling form to between and depending on conditions. ''S. squalidus'' prefers dry, disturbed places, cultivated and waste ground, walls and railway banks,〔 flowering from March to December〔 and reproduces from seed.〔 ;Leaves and stems: ''S. squalidus'' have herbaceous plants whose alternate, glossy and varying from deeply pinnately lobed to undivided leaves are almost hairless with only the lower ones being stalked. Stems and leaves resemble those of the Common Groundsel (''Senecio vulgaris'')〔〔 with the exception that their lobes are more widely spaced. ;Inflorescence: ''S. squalidus'' has larger capitula than ''Senecio jacobaea'' and a more spreading habit.〔 Yellow capitula of 10-14 petals in loose clusters at the stem. The tips are pollinated by insects. Ray corollas to long, to wide.〔 :Oxford ragwort is self-incompatible and needs pollen from other plants with different self-incompatibility alleles;〔 〕 〔 〕 its own flower possess a stigma with characteristics of both the “dry” and “wet” types. :The fruiting heads are often nodding.〔 ;Seeds: Each pollinated Oxford ragwort floret matures into a bell to cylindrical shaped indehiscent achene, the shallowly ribbed fruit is light brown in colour and to long.〔 Each plant can produce approximately 10,000 fruits during the year. Image:Senecio squalidus flor.png|Mature Capitulum Image:Senecio squalidus fruto.jpg|''S. squalidus'' developing capitula. Image:Senecio squalidus hojas.jpg|Leaves and stalks of ''S. squalidus''. Image:Senetio-rupester.jpg|Capitula at different stages of development As a ''Senecio'' and a diploid ''Senecio squalidus'' is part of a species group along with S. flavus, S. gallicus, S. glaucus and S. vernalis, which are widespread geographically and interesting for the study of genetic differences in relation to the environment and plant evolution. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Senecio squalidus」の詳細全文を読む スポンサード リンク
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