Lamium galeobdolon (L.) L. in Nederland

It is the author’s opinion that Lamium galeobdolon (L.) L. can be subdivided into two subspecies, which have separate areas of distribution (fig. 1). The species was originally described from Montpellier (France), so the typical subspecies galeobdolon is the southern one [syn. subsp. montanum (Pers.) Hayek] and the northern subsp., formerly considered the typical subspecies, must be called subsp. vulgare (Pers.) Hayek. The ditferences between the subspecies are tabulated below: subsp. vulgare Stem 20—30(—40) cm, hairs exclusively on the ribs. Cauline leaves 1—2.5(—3)cm, index 1.0—1.5. Floral leaves 1.5—3.5(—4)cm, index 1.0— 1.4(-1.6). Verticillaster with 2—8 flowers. Calyx-lobes mostly 2/3 x as long as the calyx-tube. Chromosome number 2n = 18. subsp. galeobdolon Stem (25—)30—65 cm, homogeneously hairy. Cauline leaves (2—)3—10 cm, index (1.1—)1.4—2.0(—2.5). Floral leaves (2.5—)3—12 cm, index (1.4—)1.6—2.9. Verticillaster with (8—)10—20 flowers. Calyx-lobes mostly 1/2 x as long as the calyx-tube. Chromosome number 2n= 36. Like in Germany (ENDTMANN, 1966) and in Czechoslovakia (DVOŘÁKOVÁ, 1966) in the Netherlands the areas of the two subspecies reach each other. Here it is sometimes difficult to separate the subspecies. By means of a numerical investigation (fig. 2) it was possible to establish that ‘transitory forms’ as found by ENDTMANN (l.c.), do not occur in the Netherlands.