This section is from the book "British Wild Flowers In The Four Seasons", by Thomas Moore. Also available from Amazon: British Wild Flowers.
* Florets all tubular, no ray.
S. vulgaris: annual; stem 6-12 inches high, branching; leaves half-clasping, pinnatifid, the segments distant, oblong, obtuse, and together with the rachis and auricles acutely and unequally toothed, the lower ones narrowed into a stalk; heads small, in clustered racemes; florets yellow. - Groundsel. - Common everywhere. Flowers the whole year.
** Florets of the ray small, and rolled back.
S. sylvaticus: annual; stem 1-2 feet high, erect, more or less branched, hairy; leaves deeply pinnatifid, downy, the segments oblong, unequally toothed; heads corymbose; florets yellow, those of the ray sometimes wanting. - Dry and gravelly hills. Fl. July to September.
*** florets of the ray spreading, conspicuous.
S. Jacobaea: stem 2-3 feet high, smooth, striated, branched, leafy; leaves glabrous, the radical ones oblong-obovate, attenuated below, lyrate-pinnatifid, stalked, those of the stem sessile, bipinnatifid, with spreading, oblong, deeply and irregularly-toothed and cut segments, the lowermost of them much divided, clasping; florets yellow, the heads collected in erectly-branched corymbs. - Ragwort. - Waste ground. Fl. July to September.
 
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