This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This is closely related to the Salsafy and belongs to the same family (Composite), but may be distinguished by the blackish skin of its tap roots, by its broader lance-shaped oblong and pointed leaves, and by its bright-yellow flower heads.
Fig. 515. - Scorzonera (Scorzonera hispanica).
Although really a perennial plant, it is cultivated as an annual crop in the same way as the Salsafy. Being a hardier plant than Salsafy, the roots may be left in the soil in winter if necessary. Besides the ordinary variety, there is a large-rooted one called the "Giant Russian".