Dichotomous table for gallers on Pimpinella

by Hans Roskam

1a Malformations on parts above ground => 2

1b Lateral roots usually with several nodule- to spindle-shaped swellings from which originate some lateral roots. P. anisum: Meloidogyne hapla

2a On flowering or fruiting inflorescences => 17

2b On vegetative parts => 3

3a Gall formations primarily affect leaf sheaths of leaf blades of leaflets => 8

3b Galls primarily on petioles, midrib, leaf veins or on stems => 4

4 Fungi live inside galls; but fruiting bodies develop at gall surface => 5

4b The scale-covered nymphs develop in rimmed depressions on spindle- to barrel-shaped or bulging swellings of leaf sheaths or basal stem parts. P. saxifraga: Planchonia arabidis

4c Spindle-shaped one-chambered swelling of stem or rays of umbel, 5–8 x 3–5 mm; surface green, longitudinally striate; thick-walled. P. villosa: Contarinia pimpinellae

5a Galls- bulging, soon bearing sori of rust fungi => 6

5b Galls as small, closed warts on the leaf axis, also on leaflets and stems. P. major, saxifraga: Physoderma hemisphaericum

5c Galls elongate spindle-shaped, a few to several (15) mm long; glabrous, at first vitreous, yellow-green, then ± browned. On the veins and axis of leaves, also on stem parts, usually close to ground. Many spores close to vascular bundle. P. major, saxifraga: Protomyces macrosporus

6a Galls bearing countersunk aecia and spermogonia => 7

6b Ridges on leaves with variable long, yellow-margined slight bulges, from which erupt cinnamon-to dark brown telia. P. major, siifolia: Puccinia corvarensis

7a Expanded or smaller, ± spindle-shaped, yellow bulges on petioles, midrib, leaf veins; occasionally on young stems; bearing pale yellow, pustule-shaped opening aecia. Peridium not or slightly protruding, if so then glossy white and irregularly frayed. Pimpinella spp.: Puccinia pimpinellae

7b Bulges similar, but usually smaller and more strongly swollen, often vivid reddish-yellow. Aecia deeply countersunk, sometimes remaining enclosed by tissue, globular or flat, not cup-shaped. Peridium not protruding. P. anisum, major, peregrina, saxifraga: Puccinia bistortae species complex.

8a Malformations on leaflets, with or without involvement of midrib => 9

8b Leaf sheath, especially close to umbel, inflated, bulging and swollen, succulent, often lacking leaf blade, enclosing the etiolated side shoot, sometimes inducing a cone-shaped acuminate gall. Larvae orange-red. P. major, saxifraga: Jaapiella hedickei

8c Occasionally, in very similar malformations, on P. major, peregrina, saxifraga, also develops: Semiaphis pimpinellae

9a Malformations affect leaflet leaf blades as well as leaf midrib => 15

9b Malformations on leaf blades, usually without stunting of midrib => 10

10a Leaf blades folded, as in buds => 12

10b Malformation on at least partially ± unfolded leaf blades => 11

11a Apart from often only a few normal leaflets, many are rolled at margin, thickened, ± frayed, twisted and distorted, weakly pubescent. P. major, saxifraga: Aceria peucedani

11b Leaf blades that are infected during their development show pale-green, weakly inflated upward arches, covered on underside with a dense cover of white conidiophores. P. major: Plasmopara nivea

12a Rolls or folds of leaflets => 14

12b Halves of leaflets do not unfold => 13

13a The folded leaf blade is ± shortened and curled, discoloured close to the midrib. White larvae develop between the ± distinctly thickened folds. P. major, saxifraga: Macrolabis sp.

13b Similar gall, but midrib usually bent and thickened: Contarinia sp.

14a Leaflets longitudinally rolled upwards, ± thickened. White midge larvae inside. P. saxifraga: Unidentified gall midge

14b Leaflets curled upwards or folded. Galls sometimes ± yellowish, also reddish, transversely undulate and partially twisted. P. major, peregrina, saxifraga: Semiaphis pimpinellae and/or Hyadaphis foeniculi

15a Malformations caused by aphids or psyllids => 16

15b Midrib over the tip or laterally ± conspicuously bent, with accordingly clustered, curled, deflected, locally deep green leaflets. P. anisum, major, saxifraga: Philaenus spumarius

16a Midrib of young leaves stunted. Leaf segments deflected, ± curled, slightly discoloured; with black aphids on underside. P. anisum, major: Aphis fabae

16b Leaf segments ± deflected at margin, with protrusions up to 5 mm wide, not discoloured, usually on upper side. Midrib of infected developing leaves severely stunted. P. anisum, major: Trioza apicalis s. l.

17a On flowers or fruits => 22

17b On ± expanded parts of inflorescence => 18

18a Malformation of large parts or complete inflorescence => 19

18b Centre of umbel or stalk of umbel ± swollen, club-shaped. Inner wall lined with mycelium. Containing a red larva. Pimpinella spp.: Lasioptera carophila

19a Malformations caused by aphids or thrips => 20

19b Inflorescence ± stunted, flower parts, usually with exception of aborted ovaries, greening and leafy. P. major, saxifraga: Aceria peucedani

20a Malformations associated with variously stunted axial parts or clustering of umbels. Sheaths of bracts usually ± swollen, bladder-like, and discoloured violet-red. Flowers undeveloped or ± greened; caused by aphids => 21

20b Gall-like malformations on flower buds or flowers caused by froth-covered nymphs or by very agile adult thrips. P. saxifraga: Unidentified thrips

21a Aphid green. P. major, peregrina, saxifraga: Semiaphis pimpinellae

21b Aphid black. P. saxifraga: Aphis fabae

22a On fruits => 24

22b Flowers globular, swollen, unopened => 23

23a Galls on P. saxifraga, rarely on P. major, ± globular, often reddened. Containing a sulphur- or lemon- yellow jumping midge larva: Diodaulus traili

23b On P. major, rarely on P. saxifraga. Larvae dark orange-coloured, jumping: Contarinia umbellatarum

24a Usually only one mericarp strongly inflated, bladder-like; distinctly protruding from the umbel. Wall thin, often reddened. Containing 1 (2–3) orange-red larvae. P. anisum, major, saxifraga, tragium: Kiefferia pericarpiicola

24b Young fruits slightly disfigured, shortened, rounded; mericarps not splitting up; containing pale brown-red or yellowish olive-coloured smut spores. P. saxifraga: Thecaphora pimpinellae

mod 30.iii.2020