Erodium L’Hér.

2. Erodium L’Hér. View in CoL 1

Annual to perennial herbs usually with hermaphrodite flowers, rarely dioecious. Leaves mostly opposite, usually longer than wide, pinnatifid to pinnate, or rarely undivided, usually with appressed hairs. Inflorescence an umbel (rarely reduced to a single flower), subtended by 2 or more usually scarious bracts. Flowers actinomorphic or slightly zygomorphic. Stamens 5, antesepalous, with a nectary at the base of the filament, alternating with 5 scale-like staminodes. Mericarps indéhiscent, separating from the base upwards, retaining during dispersal the outer part of the style as a long beak, which in most species becomes twisted into a spiral at maturity, the pitch of the spiral varying with the humidity. Stigmas 5, filiform.

In some species the principal leaflets of the leaf alternate irregularly with very much smaller lobes or leaflets. The latter are referred to as intercalary lobes or leaflets.

The sepals of most species are accrescent. The measurements below refer to the fruiting condition, and include the terminal mucro or arista.

At the top of the mericarp, near the base of the style, are two flattened areas or depressions, referred to below as pits, which in some species are divided into two or more sections by one or more ridges. As the ridges lie near the lower margin of the pit, the impression created is of a pit with one or more furrows below it, and this terminology is used in the descriptions. Literature: R. Knuth in Engler, Pflanzenreich 53 (IV. 129): 221-290 (1912). F. Vierhapper, Verh. Zool.-Bot. Ges. Wien 69: 112-155 (1919). 1 Leaves undivided, pinnatifid or pinnatisect, sometimes compound at the base, but if so with only 1(-2) pairs of distinct leaflets

2 Beak of fruit not more than 17 mm

3 Leaves at least 3 cm wide

4 Apical pits of mericarp with a furrow at the base

6. malacoides 4 Apical pits of mericarp without a furrow at the base

7. alnifolium 3Leaves less than 3 cm wide

5 Annual; apical pits of mericarp with a furrow at the base

6 Petals twice as long as sepals; flowers in umbels of 2-5

9. sanguis-christi

6 Petals rarely exceeding sepals, often absent; flowers solitary, rarely in pairs 8. maritimum 5 Perennial; apical pits of mericarp without a furrow at the base

7 Leaves grey-green, villous or densely pubescent; pedicels with numerous patent hairs 10. corsicum 7 Leaves green, sparsely hairy; pedicels with usually few appressed hairs 11. reichardii 2 Beak of fruit more than 17 mm

8 Plant acaulescent (S. Spain) 3. boissieri 8 Plant normally caulescent

9 Perennial

10 Beak of fruit not more than 40 mm

11 Sepals 5-7 mm; mericarps less than 5 mm 4. chium 11 Sepals 10-12 mm; mericarps c. 8 mm 12. ruthenicum 10 Beak of fruit more than 40 mm

12 Roots tuberous; beak of mericarp with long, yellowish hairs on inner face (Kriti) 34. hirtum 12 Roots not tuberous; beak of mericarp with inner face glabrous, but usually with hairs on basal part of outer face

13 Leaves divided to midrib, at least near the base; lobes oblong, pinnatifid or incise-dentate

14 Sepals c. 12 mm, with arista 2-3 mm 12. ruthenicum 14 Sepals c. 8 mm, with arista 1 mm 21. alpinum 13 Leaves divided for not more than j of the distance to midrib; lobes ovate to orbicular, usually crenate

15 Bracts suborbicular, glabrous; mericarps c. 5 mm,

with beak 40-60 mm 1. gussonii 15 Bracts triangular-lanceolate, hairy; mericarps c. 9 mm,

with beak 65-100 mm 2. guttatum 9 Annual or biennial

16 Bracts at base of umbel 2, suborbicular to reniform

5. laciniatum 16 Bracts at base of umbel at least 3, ovate to lanceolate

17 Beak of fruit less than 45 mm

18 Apical pits of mericarp with a furrow at the base

6. malacoides 18 Apical pits of mericarp without a furrow at the base

19 Beak of fruit more than 25 mm; leaves lobed 4. chium 19 Beak of fruit less than 25 mm; leaves not lobed

7. alnifolium 17 Beak of fruit more than 45 mm

20 Apical pits of mericarp with two conspicuous furrows at the base 14. botrys 20 Apical pits of mericarp without furrows, or with a single shallow one

21 Mericarps 6-7 mm; sepals 7-10 mm 13. hoefftianum 21 Mericarps 9-14 mm; sepals 12-20 mm

22 Leaf with intercalary lobes or leaflets; apical pits of mericarp glandular-hairy 16. ciconium 22 Lobes of leaf diminishing regularly from base to apex; apical pits of mericarp smooth or foveolate,

not hairy 15. gruinum I Leaves pinnate for most of their length (sometimes pinnatisect towards the apex)

23 Intercalary leaflets, much smaller than the principal ones, present

24 Annual or biennial 16. ciconium 24 Perennial, with stout, woody rhizome

25 Petals yellow 18. chrysanthum 25 Petals pink, purple or white

26 Plant acaulescent (France and Spain)

27 Leaves densely white-sericeous above, green and

± glabrous beneath 22. rupestre 27 Leaves without a conspicuous difference in indumentum between the two surfaces

28 Leaves glabrous to sparsely strigulose, with linear segments; petals 15-20 mm 24. rodiei 28 Leaves usually densely hairy, with ovate-oblong to lanceolate segments; petals not more than 13 mm

23. petraeum 26 Plant caulescent (S.E. Europe and Italy)

29 Leaves silvery-sericeous on both surfaces 17. guicciardii

29 Leaves ± hairy, but not silvery

30 Leaflets pinnatifid or somewhat pinnatisect, with oblong-lanceolate segments; flowers hermaphrodite

21. alpinum

30 Leaflets pinnate or deeply pinnatisect, with linear segments; dioecious

31 Leaves not more than 5 cm, green, with usually rather few glandular hairs; beak of fruit usually more than

40 mm 19. absinthoides

31 Leaves up to 10 cm, greyish, with numerous eglandular hairs; beak of fruit not more than 40 mm

20. beketowii 23 Intercalary leaflets absent 32 Plant caulescent 33 Most of the leaflets divided less than half-way to the midrib; apical pits of mericarp glandular 26. moschatum 33 Most of the leaflets divided more than half-way to the midrib; apical pits of mericarp eglandular 25. cicutarium 32 Plant acaulescent 34 Bracts herbaceous, united to form a cupule 33. manescavi 34 Bracts scarious, free or united only at base 35 Annual or biennial 25. cicutarium 35 Perennial

36 Many of the leaflets, at least of the later leaves of the season’s growth, entire 31. astragaloides

36 Leaflets of well-grown plants all pinnatifid or pinnatisect

37 Mericarps 7-5-9 mm 32. dauerndes

37 Mericarps 5-7 mm 27-30. acaule group