15. Gentianella Moench, Methodus. 482. 1794. name conserved.
Gentian [Genus name Gentiana and Latin -ella, diminutive, alluding to resemblance]
James S. Pringle
Aloitis Rafinesque; Amarella Gilibert, name rejected; Arctogentia Á. Löve
Herbs annual or biennial [perennial], chlorophyllous, glabrous. Leaves cauline, opposite [whorled], sometimes also basal. Inflorescences cymes or solitary flowers; pedicels mostly shorter than surrounding internodes. Flowers 4- or 5-merous; calyx with tube cylindric to narrowly campanulate or sometimes very short, sometimes with 1 or 2 sepals distinct to base or nearly so, or rarely cleft on 1 side and spathiform (G. wislizeni); corolla blue, blue-violet, rose-violet, pink, pale yellow, or white, [red, bright yellow, green, bicolored], tubular, funnelform, campanulate, or nearly salverform [nearly rotate], adaxially with or without a fringe of separate trichomes or a deeply fringed scale near the base of each lobe, lobes shorter than tube or ± as long (G. tortuosa) [longer than tube], margins entire or nearly so, without plicae between lobes, spurs absent; stamens inserted near or below [above] middle of corolla tube; anthers distinct; ovary sessile, subsessile, or short-stipitate; style persistent, erect, short or indistinct; stigmas 2; nectaries 1 [rarely 2] per petal, on corolla tube near base. Capsules compressed-cylindric to compressed-ovoid (G. aurea and G. tortuosa). x = 9, 12.
Species ca. 250 (10 in the flora): nearly worldwide except in Africa; temperate to arctic and alpine regions.
Gentianella in the flora area includes some species having vascularized fringes of trichomes or deeply fringed scales near the throat of the corolla and other species lacking any such fringes, vascularized or not. Molecular studies indicate that Gentianella circumscribed to include both of these groups (but excluding Asiatic species with paired nectaries) is monophyletic and that each of the two groups as traditionally defined is very largely monophyletic. Gentianella microcalyx is an exception, evidently being more closely related to the species with fringed corollas although it lacks fringes itself (K. B. von Hagen and J. W. Kadereit 2001). These two groups have occasionally been distinguished at generic rank, species 1 through 7 being retained in Gentianella and species 8 through 10 being placed in Aloitis. When both groups are retained in Gentianella, they have sometimes been designated sect. Gentianella and sect. Arctophila (Grisebach) Holub, respectively.
The corolla fringes normally present in species 1 through 6 may be reduced or absent on small flowers on the proximal branches or on flowers produced late in the season, or on all flowers of the smallest plants.
SELECTED REFERENCES Gillett, J. M. 1957. A revision of the North American species of Gentianella Moench. Ann. Missouri Bot. Gard. 44: 195–269. Hagen, K. B. von and J. W. Kadereit. 2001. The phylogeny of Gentianella (Gentianaceae) and its colonization of the Southern Hemisphere as revealed by nuclear and chloroplast DNA sequence variation. Organisms Diversity Evol. 1: 61–79.
