This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Intybus sativa latifolia five endivia vulgaris C. B. Cichorium endivia Linn. Endive: a common culinary plant, resembling cichory in the flowers and seeds; and differing from it chiefly in being annual, and in the leaves being shorter, broader, and only slightly crenated, not jagged, about the edges.
Endive agrees with cichory in quality as in appearance; containing, like it, a milky juice, of a bitterish taste, which it loses on being blanched by culture: the greener the colour of the leaves, the greater is the bitterness of the whole plant. In its bitterest state, however, it is somewhat less so than the cichory.