Euphrasia L.

29. Euphrasia L. 2

Annual (rarely perennial) hemiparasitic herbs. Leaves opposite, crenate to incise-dentate. Flowers zygomorphic, in bracteate, terminal, spike-like racemes. Bracts (floral leaves) large and leaflike; bracteoles absent. Calyx tubular or campanulate, 4-lobed. Corolla white to purple, marked with deep violet lines, and with yellow spots on lower lip and throat; limb 2-lipped, the upper lip galeate, the lower longer, flat, patent, 3-lobed with emarginate lobes. Stamens 4, didynamous; loculi parallel, spurred, one loculus with a much longer spur than the other. Stigma capitate. Capsule loculicidal; seeds numerous.

Most of the species are very variable and weakly differentiated, and they hybridize readily; the taxonomy of the genus is, therefore, difficult. Populations frequently occur in which one character falls outside the normal range of variation and hybrids sometimes occur independently of the parents, as well as commonly with them. The most frequent hybrids are mentioned below.

Although with sufficient experience it is possible to assign the great majority of populations to a species, it is extremely difficult to provide rigidly diagnostic descriptions and consequently to construct a key. The keys given here are designed to be used with population-samples, not with individual plants. It is therefore necessary to have a representative sample of a population taken from a small area, and to ignore extreme states of each character.

The keys make no allowance for extreme and relatively rare variants or for hybrids; otherwise it would have been necessary to prefix ‘usually’ to almost every phrase. Determinations should, therefore, be checked by reference to a good herbarium.

The most important taxonomic characters are length of internodes; node at which the lowest flower is situated; number of branches; shape, size and indumentum of leaves; size of corolla; size, shape and indumentum of capsule. In this account the presence or absence of eglandular or short glandular hairs is not regarded as very important; the presence or absence of long glandular hairs is, however, an important character.

The nodes are counted from the base, excluding the cotyledonary node; measurements of leaves and internodes refer to those on the main stem; ‘lower floral leaves’ indicates those of the lowest four flowering nodes. The length of the corolla is measured from the base of the tube to the apex of the upper lip in its normal condition in vivo, i.e. with the lobes erect or recurved. Measurement of dried specimens in which the lobes of the upper lip have become fully extended in pressing adds 0-5-1 mm to the length.

The name E. officinalis L. is variously used by modern authors as a ‘collective species’ to comprise many (or even nearly all) of the species described below. The type of E. officinalis is a mixture of 3 and 17. P. D. Sell and P. F. Yeo, Bot. Jour. Linn. Soc. 63: 201 (1970) have selected the specimen of 3 as lectotype, but reject the name E. officinalis as a nomen ambiguum . Literature: R. von Wettstein, Monographie der Gattung Euphrasia . Leipzig. 1896. A. Chabert, Bull. Herb. Boiss. ser. 2, 2: 121-152, 265-280, 497-520 (1902). E. Joergensen, Bergens Mus . Aarb. 1916-1917, Naturvid. Roekke 5: 1-337 (1919). H. W. Pugsley, Jour. Linn. Soc. London (Bot.) 48: 467-544 (1930); Jour. Bot. (London) 74: 273-288 (1936). M. Smejkal, Biol. Prace Slovensk. Akad. Vied (Bratislava) 9(9): 1-83 (1963). 1 Perennial; leaves all ± similar, with up to 12 teeth on each side

(Açores) 2 Cauline leaves suborbicular; calyx not more than 7-5mm;

capsule obcordate 1. grandiflora 2 Cauline leaves deflate; calyx c. 9-5 mm; capsule acuminate

2. azorica 1 Annual; lower leaves markedly different in shape from upper,

none with more than 9 teeth on each side 3 Middle and upper leaves bearing glandular hairs with multicellular stalk c. 10-12 times as long as the gland 4 Capsule more than twice as long as wide 11. arctica 4 Capsule not more than twice as long as wide

(3-8). rostkoviana group 3 Middle and upper leaves without glandular hairs, or glandular hairs with stalk of 1-2 cells, not more than 6 times as long as the gland 5 Anthers light yellowish-brown 6 Corolla 7-11 mm 22. christii 6 Corolla not more than 6 mm 7 Corolla 3-3-5 mm; lower floral leaves with obtuse teeth

38. bottnica 7 Corolla 4-5-6 mm; lower floral leaves with acute teeth

40. taurica 5 Anthers dark brown or purplish 8 Capsule glabrous, or with a few small cilia; at least some leaf-teeth distant

9 Floral leaves usually entire except forapair ofteeth situated near the apex, not more than 1 -5 mm long, and shorter than the width of the remainder of the leaf (S.E.

Alps) 46. tricuspidata 9 Some floral leaves with at least 2 teeth on each side, which are either more than 1 -5 mm long or longer than the width of the remainder of the leaf

10 Lower floral leaves with 1—2(—3) teeth on each side

11 Corolla at least 8 mm 45. cuspidata 11 Corolla not more than 7-5 mm

12 Lower floral leaves with linear terminal lobe and long, narrowly falcate, acute but not aristate teeth 44. dinarica 12 Lower floral leaves with lanceolate terminal lobe and long, narrow, aristate (rarely deflate, acute) teeth

41. salisburgensis 10 Lower floral leaves with (3-)4 or more teeth on each side

13 Corolla 8-9 mm 42. portae 13 Corolla not more than 7- 5 mm

14 Teeth of lower floral leaves much longer than width of remainder of leaf; corolla purplish 43. illyrica 14 Teeth of lower floral leaves not much longer than width of remainder of leaf; corolla white

41. salisburgensis 8 Capsule cibate with long, fairly numerous hairs; all leafteeth usually contiguous

15 Corollamorethan7-5 mm

16 Lowest flower at node 1 -3

17 Cauline and lower floral leaves narrowly obovate to trullate or ovate, usually crenate-serrate

(17-20). stricta group 17 Cauline and lower floral leaves elliptical to suborbicular, usually crenate 9. pietà 16 First flower at node 4 or higher

18 Basal teeth of lower floral leaves apically directed

19 Capsule not more than 2| times as long as wide

20 Corolla less than 9 mm 16. confusa 20 Corolla 9-11 mm

21 Cauline leaves ovate to oblong-ovate; lower floral leaves usually with more than 3 pairs of teeth 9. pietà 21 Cauline leaves linear-oblanceolate to narrowly trullate; lower floral leaves usually with 2-3 pairs of teeth 10. marchesettii 19 Capsule more than 2| times as long as wide

22 Stem and branches flexuous 16. confusa 22 Stem erect, with straight or regularly curved branches

23 Corolla not more than 10 mm; branches ±erect

(17-20). stricta group 23 Corolla at least 10 mm; branches ±patent

24 Lowest flower at node 9 or lower; stem with not more than 4 pairs of branches; capsule usually not more than 3 times as long as wide 21. alpina 24 Lowest flower at node 10 or higher; stem with up to 13 pairs of branches; capsule at least 3 j times as long as wide 23. cisalpina 18 Basal teeth of lower floral leaves patent

25 Lowest flower at node 8 or lower; capsule usually elliptical to obovate

26 Capsule at least twice as long as wide; leaves often with short glandular hairs 11. arctica 26 Capsule less than twice as long as wide; leaves without glandular hairs

27 Capsule not more than 5 - 5 mm 9. pietà 27 Capsule at least 6 mm 11. arctica 25 Lowest flower at node 9 or higher; capsule oblong to elliptic-oblong

28 Stem and branches usually flexuous; leaves near base of branches usually very small

29 Corolla less than 9 mm 16. confusa 29 Corolla at least 9 mm 9. pietà 28 Stem and branches usually not flexuous; leaves near base of branches not much smaller than the others 30 Teeth of floral leaves acute to acuminate; capsule usually slightly shorter than calyx; stem and branches relatively stout 13. nemorosa 30 Teeth of floral leaves mostly aristate; capsule much shorter than calyx; stem and branches relatively slender

31 Capsule usually not more than twice as long as wide; corolla at least 9 mm 9. pietà 31 Capsule usually about 2j times as long as wide; corolla not more than 9 mm 15. pseudokerneri 15 Corolla not more than 7-5 mm

32 Calyx-tube whitish and membranous, with prominent green veins

33 Capsule not more than twice as long as wide; leaves thin 35. calida 33 Capsule more than twice as long as wide; leaves thick

(28-32). ostenfeldii group 32 Calyx-tube green and herbaceous

34 Lowest flower at node 6 or higher

35 Cauline intemodes mostly 2-6 times as long as the leaves

36 Basal teeth of lower floral leaves apically directed

37 Teeth of lower floral leaves obtuse to acute, fairly short; corolla not more than 6-5 mm

38 Leaves strongly tinged with purple, not darker beneath than above; corolla usually lilac to purple; capsule shorter than calyx 33. micrantha 38 Leaves weakly or moderately tinged with purple, often darker beneath than above; corolla usually white; capsule at least as long as calyx

34. scortica 37 Teeth of lower floral leaves acute to aristate, long; corolla usually at least 7 mm

39 Basal teeth of lower leaves strongly apically directed (17-20). stricta group 39 Basal teeth of lower floral leaves only slightly apically directed

40 Capsule not more than 3 times as long as wide

11. arctica 40 Capsule at least 3 times as long as wide

(17-20). stricta group 36 Basal teeth of lower floral leaves patent

41 Corolla at least 6- 5 mm

42 Lowest flower at node 9 or higher; leaves usually without glandular hairs; lower floral leaves smaller than upper cauline 13. nemorosa 42 Lowest flower at node 8 or lower; leaves usually with glandular hairs; lower floral leaves larger than upper cauline 11. arctica 41 Corolla not more than 6-5 mm

43 Leaves densely hairy

44 Lowest flower at node 8 or lower; stem not more than 15 cm; lower floral leaves about as wide as long (28-32). ostenfeldii group 44 Lowest flower at node 9 or higher; stem up to 40

cm; lower floral leaves often longer than wide

13. nemorosa 43 Leaves sparsely hairy to subglabrous

45 Stem and branches very slender, blackish; leaves strongly tinged with purple, not darker beneath than above; corolla usually lilac to purple

33. micrantha 45 Stem and branches either stout or lightly pig­ mented; leaves weakly or moderately tinged with purple; corolla usually white

46 Lowest flower at node 7 or lower; stem slender;

leaves usually light green above and purplish beneath; capsule usually longer than calyx

34. scortica 46 Lowest flower at node 8 or higher; stem robust; leaves not darker beneath than above; capsule usually shorter than calyx

13. nemorosa

35 Cauline intemodes mostly not more than twice as long as leaves 47 Basal teeth of lower floral leaves apically directed 48 Teeth of lower floral leaves not much longer than wide (28-32). ostenfeldii group 48 Teeth of lower floral leaves much longer than wide 49 Stem and branches flexuous 16. confusa 49 Stem and branches ± straight and erect 50 Floral leaves with not more than 3 teeth on each side 40. taurica 50 Some floral leaves with more than 3 teeth on each side (17-20). stricta group 47 Basal teeth of lower floral leaves patent 51 Lowest flower at node 10 or higher 52 Stem erect, stout, with stout, ascending branches; lower floral leaves mostly opposite 13. nemorosa 52 Stem and branches slender and flexuous; lower floral leaves mostly alternate 16. confusa 51 Lowest flower at node 9 or lower 53 Leaves with numerous eglandular hairs (28-32). ostenfeldii group 53 Leaves with few eglandular hairs 54 Stem branched from near the base; branches ascending, curved at base, terminating in long, dense spikes similar to that on main stem 12. tetraquetra 54 Stem not branched much below the middle; branches straight, erecto-patent, not termi­ nating in long, dense spikes 11. arctica 34 Lowest flower at node 5(-6) or lower 55 Cauline internodes mostly at least 2J times as long as the leaves 56 Capsule broadly elliptical to obovate-elliptical 57 Cauline intemodes up to 9 times as long as the leaves; lower floral leaves ovate to rhombic, with teeth all apically directed 36. saamica 57 Cauline intemodes rarely more than 4 times as long as the leaves; lower floral leaves ± broadly ovate to suborbicular, with basal pair of teeth ± patent 58 Teeth of lower floral leaves mostly subacute and not longer than broad; corolla 4-5-7 mm; lowest flower at node 2-4(-5) 25. frigida 58 Teeth of lower floral leaves usually acute or acuminate and longer than broad; corolla at least 6-5 mm; lowest flower usually at node 4 or higher 11. arctica 56 Capsule oblong to narrowly elliptical 59 Lower floral leaves deeply serrate to pectinate; basal teeth apically directed (17-20). stricta group 59 Lower floral leaves crenate or shallowly serrate; basal teeth usually patent 60 Upper cauline leaves elliptic-ovate to narrowly obovate 61 Leaves usually light green above and purplish beneath; branches long; capsule usually more than twice as long as wide 34. scottica 61 Leaves ±concolorous; branches short; capsule not more than twice as long as wide 14. coerulea 60 Upper cauline leaves suborbicular to broadly ovate or broadly obovate 62 Lowest flower at node 4 or lower; lower floral leaves often considerably larger than the upper cauline 63 Stem straight, erect; cauline leaves distinctly petiolate, with distal teeth incurved; corolla rarely more than 5 -5 mm, the lower lip usually yellow 24. minima 63 Stem often flexuous; cauline leaves obscurely petiolate, with distal teeth not incurved; corolla up to 7(-8) mm, the lower lip white or purple 25. frigida 62 Lowest flower at node 4 or higher; lower floral leaves scarcely larger than the upper cauline 64 Leaves densely hairy, without distinct petiole (28-32). ostenfeldii group

64 Leaves usually sparsely hairy to subglabrous,

with short but distinct petiole 24. minima

55 Cauline internodes mostly less than 2j times as long as

the leaves

65 Corolla at least 6 mm

66 Teeth of lower floral leaves usually very acute, all

apically directed

67 Stem and branches slender, flexuous; lower floral leaves mostly alternate 16. confusa

67 Stem and branches usually stout, rigid; lower floral leaves mostly opposite (17-20). stricta group

66 Teeth of lower floral leaves subacute to acute, the

basal pair patent

68 Capsule at least as long as the calyx, usually emarginate 25. frigida

68 Capsule shorter than the calyx, truncate or slightly emarginate 12. tetraquetra

65 Corolla not more than 6 mm

69 Lower floral leaves ovate to rhombic, with acute to

aristate teeth, the basal pair apically directed

70 Leaves with very short glandular hairs; floral leaves with not more than 3 teeth on each side;

capsule apiculate (Krym) 40. taurica

70 Leaves usually eglandular; floral leaves often with more than 3 teeth on each side; capsule scarcely

apiculate

71 Corolla deep purple (Faerôer) 37. atropurpurea

71 Corolla white to lilac

72 Stem and branches flexuous 16. confusa

72 Stem and branches straight, erect

73 Lowest flower at node 4 or lower 39. willkommii

73 Lowest flower at node 5 or higher (17-20). stricta group

69 Lower floral leaves broadly ovate or deflate to

suborbicular, with obtuse to subacute teeth, the

basal pair patent

74 Leaves with numerous eglandular hairs and without glandular hairs

75 Lower floral leaves scarcely larger than the upper cauline (28-32). ostenfeldii group

75 Lower floral leaves considerably larger than the upper cauline

76 Stem straight, erect, usually with 1 -3 pairs of branches; cauline leaves distinctly petiolate,

with distal teeth incurved 24. minima

76 Stem often flexuous, with not more than 2 pairs

of branches and often simple; cauline leaves

obscurely petiolate, with distal teeth not in­

curved 25. frigida

74 Leaves with few eglandular hairs, sometimes with short glandular hairs

77 Capsule elliptical to obovate, emarginate; corolla

not more than 5- 5 mm, with very small lower

lip 27. cambrica

77 Capsule oblong to elliptic-oblong, usually trun­ cate; corolla up to 7 mm, with conspicuous

lower lip

78 Distal teeth of lower floral leaves usually in­ curved; capsule usually exceeding calyx

26. foulaensis

78 Distal teeth of lower floral leaves not incurved; capsule usually shorter than calyx 12. tetraquetra