Gentianella Moench

Plants monocarpic and annual or biennial, or polycarpic and flowering each year; herbaceous (occasionally semi-woody). Leaves and stems glabrous. Caudex short and not distinct (< 10 mm) to long and distinct (c. 150 mm), branched or unbranched; dead leaves caducous and leaving scars, or persistent and forming a shaggy layer on the caudex; new branches sometimes arising from old parts of the caudex. Leaves usually in rosettes, occasionally a rosette lacking in biennial plants in their second year, rosette either at the base of the terminal stem (in most monocarpic species) or at the apex of each branch (in most mature polycarpic species), opposite, decussate, sessile to petiolate, entire, elliptic, narrowly elliptic or linear, channelled to flat. Flowering stems single or multiple, either terminal from the rosette apex, or lateral from leaf axils below the rosette apex, erect to decumbent; with 1–6 pairs of opposite leaves that grade to being sessile in the upper parts of the stem, with four vertical ribs. Flowers scentless, protandrous, (4–)5(–6)-merous, on short to long pedicels that are square in section, terminal and solitary or terminal and lateral in dichasial cymes arising from scape leaf axils, 1–2 per axil. Calyx campanulate, lobed ×0.6–0.85 from the apex, lobes slightly to strongly unequal in length and width, slightly Vshaped, usually erect, occasionally recurved, triangular to subulate, lobe margins smooth or papillose, apices acute (occasionally rounded), sinus narrowly to broadly acute, usually with a few hairs; the cup smooth or roughened, with hairs usually present on the inner surface, particularly at the calyx–corolla fusion line. Corolla campanulate, lobes overlapping in bud contorted to the right, lobed ×0.65–0.83 from the apex, lobes parting at anthesis to form a narrow- throated fl ower, or widely separating to form a stellar and salviform fl ower; corolla completely white, sometimes with tinting of grey-violet, pink, blue, dark purple, or crimson in various parts of the corolla but usually at the apices on the outside surface, corolla rarely coloured uniformly, then pale yellow, veins colourless or crimson, purple, dark purple, or grey-violet; corolla tube white, green, or occasionally yellow; lobe sinuses a narrow slit, hairs usually present on the inner corolla surface between the sinus and line of fusion of the fi lament to the corolla and as a ring just above the fusion line. Nectaries 0.4–1.5 mm from corolla base, alternate to and between the fi laments, yellow to green, V- or U-shaped, bulbous or forming a pocket with a variably developed flap or two flaps, the flap when well developed sometimes with a toothed margin. Stamens alternating with the corolla lobes, medifi xed, fi laments fl attened, pale translucent green. Anthers versatile, introrse before dehiscence, usually extrorse at dehiscence, sometimes remaining introrse or becoming horizontal at dehiscence, bilocular, locules oblong, purple-black, yellow, or orange, dehiscing on the long axis outer wall, the mouth with a yellow, orange, or red border. Male sterility occasional, in the form of anthers reduced or absent. Pollen yellow, rarely black through staining by the anther wall, 35–45 µm diam., tricolpate, surface pattern surface striate or striate-reticulate, rarely reticulate. Ovary fusiform, unilocular with two opposite suture lines the length of the ovary, colour yellow, sometimes tinted blue or purple after fertilisation, style absent; stigma shortly bivalved, arms c. 0.7 mm long, stigmatic surface with clear or blue to purple-tinted clavate cells. Ovules attached by a short stalk to the inner surface of the outer ovary wall, in 4 equal rows, (2–)10–60(–80) per ovary. Capsule septicidal at the mouth, dry, brown, and leathery when seeds are ripe. Seeds spherical, c. 1.0 mm diam., pale to dark brown, densely rugose (at 40× magnification) with a fine overlying reticulum (SEM). (All characters based only on New Zealand species).

[Reproduced from Glenny (2004, New Zealand J. Bot. 42: 361-530) with permission from The Royal Society of New Zealand.]