Herbs, rarely (non-Australian) saprophytes, vines, shrubs or small trees. Leaves opposite and decussate, or rarely (non-Australian) alternate, simple and entire, usually sessile, exstipulate. Inflorescence usually cymose or flowers solitary. Flowers usually actinomorphic, 4- or 5- (6–9)-merous, usually bisexual. Calyx tube short to elongate; lobes imbricate to valvate or open in bud, rarely absent. Corolla sympetalous; tube short to elongate; lobes contorted in bud, sometimes plicate in sinuses. Stamens usually perigynous, variously inserted in corolla tube, alternate with lobes, rarely some staminodal or obsolete; anthers bilocular. Nectaries often present, either as scales or pits on corolla tube, or as disc or glands surrounding base of ovary. Ovary superior, bicarpellate, 1- (or 2)-locular; ovules ± numerous; placentation parietal, axile or free-central; style simple or absent; stigma 1, entire or bifid, or stigmas 2, smooth or ± papillose. Gynophore sometimes present. Fruit a septicidal capsule or rarely (not in Australia) a berry. Seed with small, straight embryo embedded in oily endosperm.

A family of about 80 genera and 1100 species, essentially cosmopolitan but, apart from a small, woody, mainly neotropical group, predominantly in montane, temperate climates of the northern hemisphere and S America. There are 8 genera and 31 species in Australia.

In the following account: (1) height of stem is measured from its base to top of inflorescence; (2) internode number is measured to base of terminal inflorescence on primary flower stem; (3) flower diameter is measured with petals fully spread; and (4) anther length refers to fresh or reconstituted material.

The family is of little economic importance apart from bitter principles in a few genera having medicinal value, and others providing a number of beautiful 'alpine garden' ornamentals. The corollas of some taxa, particularly Gentiana species, are markedly temperature- and touch-sensitive (Pijl 1940, Pringle 1979). Harley (1969) reported species of most genera develop mycorrhizal associations, including some with Rhizoctonia as in some orchids.

Over the years there has also been a great deal of debate regarding problems of generic limits within the family, particularly in the subtribe Gentianinae and mainly centred around Gentiana s. lat. General agreement in this area is still awaited, opinions varying from extreme conservatism to the need for radical revision; arguments for the latter view, largely based on karyology, are made by A. & D. Löve (1976). For concise overviews of the infrafamilial and generic situation see Philipson (1972), Wood & Weaver (1982) and Ho & Liu (1990), and comprehensive discussion of Gentiana L. can be found in N.I. Kusnezov (1896–1904). All genera represented in Australia fall within the tribe Gentianeae sensu Wagenitz (1964) and are arranged here with the same sequence as in that work.

Up until relatively recently (e.g. Lawrence 1951) there was wide acceptance of a broader taxonomic circumscription for the family, to include all taxa of the family Menyanthaceae Dumort. However, throughout this century, evidence has been accumulating (e.g. Lindsey, 1940) in support of their segregation, currently resulting in almost unanimous acceptance of the two separate families (e.g. Clapham et al. 1962, Wagenitz 1964, Eichler 1965, Tutin et al. 1972, Cronquist, 1981, Wood & Weaver 1982, Stace 1991).

A.L. de Jussieu, Gentianae, Gen. Pl. 141 (1789); A.H.R. Grisebach, Gen. Sp. Gent. (1838); A.H.R. Grisebach, Gentianaceae, in A.L.P.P. de Candolle, Prodr. 9: 39–141, 561–563 (1845); G. Bentham, Gentianeae, Fl. Austral. 4: 369–374 (1868); E.F. Gilg, Gentianaceae, in H.G.A. Engler & K.A.E. Prantl (eds), Nat. Pflanzenfam. IV 2: 50–108 (1895); N.I. Kusnezow, Subgenus Eugentiana Kusn., Trudy Imp. S.-Peterburgk. Bot. Sada 15: 1–507 (1896–1904); J.M. Black, Gentianaceae, Fl. S. Australia 459 (1926); G. Hegi, Gentianaceae (incl. Menyanthaceae), Ill. Fl. Mitt.-Eur. 5(3): 1953–2047 (1927); A.A. Lindsey, Floral anatomy in the Gentianaceae, Amer. J. Bot. 27: 640–651 (1940); L. van der Pijl, On the sensitive flowers of Gentiana quadrifaria, Ann. Jard. Bot. Buitenzorg 49(2): 89–98 (1940); D. Wilkie, Gentians (1950); G.H.M. Lawrence, Gentianaceae (incl. Menyanthaceae), Taxon. Vasc. Pl. 670–672 (1951); R.W. Butcher, Gentianaceae, New Ill. Brit. Fl. 2: 151–169 (1961); A.R. Clapham et al., Gentianaceae, Fl. Brit. Isles 2nd edn, 640–648 (1962); H. Toyokuni, Conspectus gentianacearum japonicarum, J. Fac. Sci. Hokkaido Imp. Univ., Ser. 5, Bot. 7: 137–259 (1963); G. Wagenitz, Gentianaceae, in H. Melchior (ed.), Syllabus 12th edn, 2: 408–410 (1964); H. Eichler, Gentianaceae, Suppl. Black's Fl. S. Australia 259 (1965); H. Toyokuni, Systema Gentianinarum novissimum: facts and speculation relating to the phylogeny of Gentiana, sensu lata and related genera, Symb. Asahikawensis 1: 147–158 (1965); G.K. Brizicky, Subgeneric and sectional names: their starting points and early sources, Taxon 18: 655–658 (1969); J.L. Harley, The Biology of Mycorrhiza 2nd edn, 235–236 (1969); W.R. Philipson, The generic status of the Southern Hemisphere gentians, Advances Pl. Morphol. 1972: 417–422 (1972); T.G. Tutin et al., Gentianaceae & Menyanthaceae, Fl. Europaea 3: 56–67 (1972); T. Karlsson, Recurrent ecotypic variation in Rhinantheae and Gentianaceae in relation to hemiparasitism, Bot. Not. 127: 527–539 (1974); M. Bartlett, Gentians (1975); A. & D. Löve, The natural genera of Gentianinae, in P. Kachroo (ed.), Recent Advances Bot. 205–222 (1976); J.S. Pringle, Taxonomy and distribution of Gentiana (Gentianaceae) in Mexico and Central America. II. sect. Chondrophyllae, Sida 8: 14–33 (1979); L.H. Cramer, Gentianaceae, in M.D. Dassanayake (ed.), Fl. Ceylon 3: 55–78 (1981); A.J. Cronquist, Gentianaceae, Integr. Syst. Class. Fl. Pl. (1981); C.E. Wood & R.E. Weaver, The genera of Gentianaceae in the southeastern United States, J. Arnold Arbor. 63: 441–487 (1982); R.J. Hnatiuk, Gentianaceae, Census Austral. Vasc. Pl. 234–235 (1990); T.N. Ho & S.W. Liu, The infrageneric classification of Gentiana (Gentianaceae), Bull. Brit. Mus. (Nat. Hist.) Bot. 20: 169–192 (1990); C.A. Stace, Gentianaceae, New Fl. Brit. Isles 614–621 (1991); G.J. Harden, Gentianaceae, in G.J. Harden (ed.), Flora of New South Wales 3: 508–512 (1992); I.R.H. Telford, Gentianaceae, Flora of Australia 50: 317–318 (1993); P.S. Green, Gentianaceae, Flora of Australia 49: 273–274 (1994); L.G. Adams, Gentianaceae, in A. Wilson (ed.), Flora of Australia 28: 72–104 (1996); N.G. Walsh, Gentianaceae, in N.G. Walsh & T.J. Entwisle (eds), Flora of Victoria 4: 310–321 (1999); G. Mansion, G., A new classification of the polyphyletic genus Centaurium Hill (Chironiinae - Gentianaceae): description of the New-World endemic Zeltnera, and reinstatement of Gyrandra Griseb., and Schenkia Griseb., Taxon 53(3): 719–740 (2004).

L.G. Adams, Gentianaceae, in A. Wilson (ed.), Flora of Australia 28: 72–104 (1996).