Umbilicus horizontalis, (Guss.) DC.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 352

5. U. horizontalis (Guss.) DC. , Prodr. 3: 400 (1828)

( Cotyledon horizontalis Guss. ).

Like 4, but with the raceme occupying not more than half the stem; cauline leaves more numerous and crowded, many of them usually linear; flowers narrower and somewhat shorter (c. 7 x 3 mm), subsessile, horizontal; and corolla-lobes triangular, lanceolate, acuminate. 2n=24. Mediterranean region, Bulgaria, Açores. Al Az BI Bu Cr G r Hs It Ju?Sa Si. The plants of the W. Mediterranean region are sometimes separated as U. gaditanus Boiss. , Diagn. Pl. Or. Nov. 1 (6): 58 (1846), and are in some features transitional to 4, but neither their taxonomic status nor their correct name can be ascertained with certainty from the material available. U. intermedius Boiss. , FI. Or. 2: 769 (1872) ( Cotyledon intermedia (Boiss.) Stefanov ), has been recorded for the Balkan peninsula (Bulgaria and Thrace), but its occurrence in Europe is doubtful. It is a plant of S.W. Asia, differing from 4 in its shorter raceme, short pedicels and slightly more pointed corolla-lobes, and from 5 by the usually drooping flowers and corolla with broader tube and lobes.