Melampyrum L.

27. Melampyrum L. 12

Hemiparasitic annuals. Leaves opposite, undivided, usually entire. Flowers in terminal, bracteate spikes or racemes. Calyx tubular, not inflated, with 4 acute, entire teeth. Corolla 2-lipped; tube cylindrical to obconical; upper lip cuculiate, usually with margins more or less recurved; lower lip with 3 short, entire lobes. Stamens 4, didynamous, included under upper lip of corolla; anther-lobes equally mucronate. Capsule loculicidal, compressed at right angles to the septum; seeds 1-4, smooth.

In this and related genera the leaves on the main stem which lie between the uppermost branches and the lowest flowers of the terminal inflorescence are known as intercalary leaves.

The species of this genus, as of some other genera of hemiparasitic Scrophulariaceae , exhibit a characteristic type of variation, which, since it is to some extent correlated with variation in the season of germination and flowering, was originally described as seasonal dimorphism; but as many species have more than two variants, and since habitat-factors unconnected with seasonal variation have been shown to be relevant, it is now sometimes referred to as ‘pseudoseasonal polymorphism ’. The variation appears to be mainly eoctypic in nature; its seasonal aspect arises largely from the selection of earlyflowering varieties in meadows which are cut for hay in mid­ summer. These variants have been very differently treated by different authors, being regarded sometimes as species, sometimes as subspecies, varieties or forms; and in many cases the information available is insufficient to distinguish between true ecotypic variation and purely phenotypic modification. The non­ committal term ‘ecotypic variant’ is therefore used. Since these variants cut across the normal pattern of geographical speciation and subspeciation it is not possible - at least until more experimental work has been done - to accommodate them satisfactorily in any taxonomic categories; on the other hand the constant nature of the intraspecific variation throughout the genus demands some recognition. The principal recurrent variants are, therefore, designated and described below for the genus as a whole, and under each species or subspecies are listed such of these variants as have been recognized within it, together with the basionym (at whatever rank this may happen to be) under which each was first validly described. Such citation does not imply approval of the appropriateness of the rank in question.

In Melampyrum the recurrent ecotypic variants are as follows:

(1) Autumnal. Branches numerous, patent or arcuate; internodes numerous, short; intercalary leaves numerous. Lateflowering. Mainly in woods and scrub.

(2) Aestival. Branches 0-2 pairs, short, non-flowering, erect; internodes few, long; intercalary leaves absent; cotyledons often present at anthesis; flowers often larger than in (1). Earlyflowering. Mainly in meadows.

(3) Montane. Branches 1-2 pairs, suberect, flowering; internodes numerous, fairly long; intercalary leaves 0-2 pairs. Leaves often fleshy. Mid-season-flowering. Mainly in mountain pastures.

(4) Segetal. Like (3) but with shorter internodes and not more than 1 pair of intercalary leaves. Mid-season-flowering. In cornfields.

Species which do not exhibit ecotypic variation usually conform in their morphology to that of the autumnal variant.

Literature: G. Beauverd, Mém. Soc. Phys. Hist. Nat. Genève 38: 291-657 (1916). C. E. Britton, Trans. Proc. Bot. Soc. Edinb. 33: 357-379 (1943). J. Jalas, Ann. Bot. Fenn. 4: 486-526 (1967). A. J. E. Smith, Watsonia 5: 336-367 (1963). R. de Soó, Feddes Repert. 23: 159-176, 383-397; 24: 127-193 (1926-1927). 1 Inflorescence dense, not secund; bracts densely imbricate, concealing the axis (Sect. Spicata )

2 Bracts cordate, folded along the midrib and with apex deflexed; inflorescence distinctly 4-angled 1. cristatum

2 Bracts not cordate, ± flat, with apex seldom deflexed; inflorescence cylindrical or obscurely 4-angled

3Lower lip ofcorolla with upturned margins; throat of corollatube closed

4 Calyx-tube glabrous except for strigulose veins; calyx-teeth conspicuously cibate 2. ciliatum 4 Calyx-tube uniformly strigulose; calyx-teeth not conspicuously cibate 3. arvense 3Lower bp of corolla with deflexed margins; throat of corollatube open

5 Calyx densely villous 4. barbatimi 5 Calyx glabrous or puberulent

6 Teeth of bracts bearing long, rigid hairs; calyx-teeth about equalling the tube; corolla with white tube and pink

bps 5. variegatum 6 Teeth of bracts pubescent; calyx-teeth l |- 2 times as long as the tube; corolla pink to violet, with white or yellow lower bp 6. limbriatum 1 Inflorescence ±lax, secund; bracts scarcely imbricate, not concealing the axis (Sect. Melampyrum )

7Bracts pectinate, with teeth ending in a flexuous arista

8-10 mm 20. heracleoticum 7Bracts entire to fimbriate, without long-aristate teeth

8 Calyx with some hairs more than 0-5 mm, at least on the veins

9 Calyx-tube with some long hairs between the veins, as well as on them

10 Hairs uniformly oriented on all parts of calyx 7. nemorosum 10 Hairs on distal part of calyx directed towards the apex, those on proximal part deflexed

(9-12). velebiticum group 9 Calyx-tube with long hairs confined to the veins; remainder of surface puberulent or glabrous

11 Calyx-teeth not more than 1 | times as long as tube

14. subalpinum 11 Calyx-teeth 2-3 times as long as tube

12 Corolla 10—12(—17) mm, with tube distinctly curved or inflected 18. scardicum 12 Corolla (12-)16-24 mm; tube ±straight

(15-17). bihariense group 8Calyx glabrous or puberulent, with hairs not more than 0-25

mm

13 At least the upper bracts violet-blue

14 Hairs on calyx patent 8. polonicum 14 Hairs on distal part of calyx directed towards the apex,

those on proximal part deflexed (9-12). velebiticum group 13 Bracts green (rarely whitish)

15 Calyx-teeth 11—14 mm 19. trichocalycinum 15 Calyx-teeth not more than 5 mm

16 Throat of corolla usually ±closed; capsule dehiscing along one margin only 24. pratense 16 Throat of corolla open; capsule dehiscing along both margins

17 Lips of corolla shorter than tube, the lower bp porrect

13. bohemicum 17 Lips of corolla equalling tube, the lower lip deflexed

(21-23). sylvaticum group