gallers on genus Gentiana

1a Galls on higher situated organs or on rosette leaves => 2

1b Rotund swellings, 2–3 mm long on root collar or stem base. G. campestris, etc.: cf. Smicronyx reichi

2a On higher situated parts or on single organs => 3

2b Leaves clustered, rosette-like. Gentianella amarella: Unidentified gall mite

3a On flowers => 7

3b On vegetative organs => 4

4a On shoot tips, axial parts of shoot or leaves => 5

4b Rotund ± one-sided ± bulging galls, up to 4 mm long, on axial parts of shoots, usually close to a node. On ± severely stunted stems symmetrical barrel- to spindle-shaped galls, up to about 8 (10) mm long. With a large chamber inside which may continue into the pith. Gentianopsis ciliata, Gentianella germanica: Smicronyx reichii

4c Stem, usually in lower half, with broad spindle-shaped one-sided flattened and often strongly deflected swelling, 6–10 mm long, containing the causer in the sharp bend below an arched scale. Gentianopsis ciliata, germanica: Planchonia arabidis

5a Malformations by other causers than aphids => 6

5b Malformations of shoots associated with atrophied flowers and discoloured leaves. Gentiana asclepiadea, cruciata: Aphis gentianae

6a Axial parts stunted and distorted on one side. Inserted leaves deflected and variously curled. Gentiana/ Gentianella spp.: Philaenus spumarius

6b Rarely developing aecia in spring on sometimes slightly bulging, oblong-oval areas on stems, flower peduncles, less so on petioles and leaf veins. Gentiana/ Gentianella spp.: Puccinia gentianae

7a Malformations caused by gall mites => 8

7b Flowers slightly disfigured, unopened. Gentiana pneumonanthe; Gentianella amarella, campestris, germanica: Dasineura gentianae

7c Capsule rarely swollen; containing a weevil larva or pupa. Gentianella amarella, campestris, germanica: Smicronyx reichii

8a Inflorescence transformed into a rosette of small leaves; flowers variously ± greened or leafy, occasionally filled with ± disfigured organs or developing further. Gentiana/ Gentianella spp.: Aculus kerneri and/or Eriophyes gentianae

8b Malformations on flowers with conspicuous wrinkling of calyx and corolla. Gentiana bavarica: Unidentified gall mite