Lathraea L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 281

39. Lathraea L. 2

Perennial herbs, wholly parasitic and without chlorophyll; leaves fleshy, scale-like. Flowers zygomorphic, in terminal racemes or corymbs. Calyx campanulate, unequally or subequally 4-lobed. Corolla with cylindrical tube and 2-lipped limb; upper lip entire, convex; lower entire or shortly 3-lobed. Stamens 4, didynamous, included under upper lip of corolla or slightly exserted from it; anther-lobes hairy, mucronate. Ovary 1 -locular, with 2 large, 2-lobed, parietal placentae. Capsule dehiscing along midribs of carpels.

Included by some authors in Orobanchaceae , but the resemblance seems to be superficial (arising from the completely parasitic habit, which is, however, also found in Scrophulariaceae ), and in many morphological features Lathraea more closely resembles such members of the Scrophulariaceae as Bartsia or Rhinanthus .

In all European species cleistogamous flowers may occur at the base of the inflorescence or underground. They have a corolla considerably shorter than that of normal flowers.

Literature: G. Beck von Mannagetta in Engler, Pflanzenreich 96(IV. 261): 317-326 (1930). E. Heinricher, Monographie der Gattung Lathraea . Jena. 1931.

1 Flowers arising from a mainly subterranean rhizome; corolla 40-50 mm 3. clandestina 1 Flowers borne on an erect, aerial stem; corolla 10-20 mm

2 Raceme secund; calyx c. 10 mm; corolla 14—17(—20) mm

1. squamaria 2 Raceme cylindrical, not secund; calyx 5-7 mm; corolla c. 10

mm 2. rhodopea