Gentianella.doc

Plant Crib
GENTIANELLA
Gentianella causes problems for four main reasons (Pritchard 1959):- i. Extensive hybridisation occurs between some of the species which may result in introgression. ii. Any one population of some species may contain both annuals and biennials, which frequently differ in such characters as habit and leaf shape. iii. Local populations show great variability in morphology which is partly related to (1) and (2).
iv. There is considerable variation between separate populations in small geographical areas.
1. Gentianella anglica / G. amarella / G. × davidiana
A morphological investigation of variation in Gentianella anglica (Pugsley) E. F. Warb. has shown that subsp. cornubiensis N. M. Pritch. is G. anglica × G. amarella = G. × davidiana T. C. G. Rich. The hybrid has been recorded from the southern English V.cc. 1, 4, 9, 10, 14 and 16, and may also occur elsewhere (Rich et al. 1997). The taxa may be distinguished as below; population means of at least 15 plants should be measured in the field but not collected as G. anglica is a protected species.
There is considerable interest in conservation of the endemic G. anglica. Populations vary enormously in
size from year to year, related to its biennial habit and climate, and also the proportions of hybrids in them
varies. Please document all localities carefully, and record on a regular basis for a series of years.
2. Gentianella × pamplinii (G. amarella × G. germanica)
G. amarella (L.) Börner subsp. amarella and G. germanica (Willd.) Börner are usually easily distinguished, but they hybridise freely and in some hybrid populations there is extensive introgression (Pritchard 1960; McVeigh et al. 2005). Occasionally slender annual forms of G. germanica may be found which may be misidentified as G. anglica when flowering early or G. amarella or the hybrid, hence examine populations carefully. Botanical Society of the British Isles in association with National Museums of Wales Plant Crib 1998 edited T. C. G. Rich & A. C. Jermy. Produced by H. B. R. Cleal. Plant Crib
G. × pamplinii (Druce) E. F. Warb. is usually intermediate but is variable, and has generally lower pollen fertility (c. 50-60% as opposed to over 90% in the parents). The main problem will be separating G. germanica from its hybrid with G. amarella: G. x pamplinii has narrower stem leaves and shorter corollas with the tube intermediate in shape between the parents. Robust, (3.5-)12-36(-54) Robust, (7.3-)13-35(-44) Smaller, (2-)3-15(-24) cm, often branched (6-)14-32(-43) mm long (13-)20-38(-49) mm long × (5-)8-14(-18) mm (2-)3-10(-18) mm wide, wide, ovate-lanceolate to wide, ovate-lanceolate
3. Gentianella uliginosa
Gentianella uliginosa (Willd.) Börner is another rare
species which has been reported from Devon and
Derbyshire (Rich 1996) in addition to its south Wales
sites. Records from Scotland are errors for small G.
amarella (Rich & Lavery, unpublished).
Key features are the annual growth habit, 0-2 pairs of
stem leaves and unequal often spreading sepals.


Botanical Society of the British Isles in association with National Museums of Wales Plant Crib 1998 edited T. C. G. Rich & A. C. Jermy. Produced by H. B. R. Cleal. Plant Crib
References Pritchard, N. M. (1959). Watsonia 4: 169-192.
Pritchard, N. M. (1960). Watsonia 4: 218-237 and 290-303.
Rich, T. C. G. (1996). Watsonia 21: 208-209.
Rich, T. C. G. (1997). Watsonia 21: 289-291.
Rich, T. C. G., Holyoak, D. T., Margetts, L. J. & Murphy, R. J. (1997). Watsonia 21:313-
McVeigh, A., Carey, J. E. & Rich, T. C. G. (2005). Watsonia 25: 339-367.
Rose, F. (1998). Watsonia 22: 114-116.
Botanical Society of the British Isles in association with National Museums of Wales Plant Crib 1998 edited T. C. G. Rich & A. C. Jermy. Produced by H. B. R. Cleal.

Source: http://www.bsbi.org.uk/Gentianella_Crib_3.pdf