2. GENTIANA, Linn.
Annual or perennial herbs. Leaves opposite. Flowers axillary and terminal, solitary or cymose, usually conspicuous. Calyx tubular or cup-shaped, 5- or rarely 4-lobed. Corolla subrotate or campanulateor tubular or funnel-shaped; lobes 5–4, in species not found in New Zealand often with folds between the lobes. Stamens 5–4, inserted on the corolla-tube, included; anthers oblong or ovate. Ovary 1-celled, with 2 parietal placentas; style short or almost wanting; stigmas 2, persistent, recurved; ovules numerous. Capsule stalked or sessile, ellipsoid to narrow-oblong, 2-valved to the base. Seeds small, globose or oblong.
A large and beautiful genus, probably including not far from 250 well-ascertained species. It is most abundant in the temperate and alpine regions of the Northern Hemisphere, extends along the chain of the Andes throughout South America, is sparingly found in Australia and Tasmania, and is plentiful in New Zealand, except in the northern half of the North Island. The species are in all countries highly variable and difficult of discrimination, but nowhere more so than in New Zealand, where they are peculiarly unstable, presenting a bewildering multitude of closely allied forms, to arrange which systematically is a most perplexing task. The late Baron Mueller solved all difficulties by uniting the whole of the Australian and New Zealand species, together with several from South America, under Forster's G. saxosa; but this extreme view has not received the sanction of any other botanist of repute, and is entirely repudiated by New Zealand workers. Since the publication of the Handbook the only attempt that has been made to deal with the New Zealand forms as a whole is Mr. Kirk's "Revision" (Transactions N.Z. Inst. xxvii. 330), in which 10 species are admitted. In the following arrangement I have increased this number to 16, in several cases unwillingly, but there is really little choice between giving the rank of species to a considerable number of closely allied forms or of reducing the whole of them to two or three comprehensive aggregates. In the latter case it would be necessary to distinguish the forms as varieties, which is practically the same arrangement under a different name. Owing to their extreme variability, the student will find it difficult to identify the species until he has collected a large series of specimens from widely separated localities, and has thus become acquainted with the range and trend of variation. I have to acknowledge the valued aid afforded by Mr. N. E. Brown, who has kindly compared many of ray specimens with those at Kew and in the British Museum Herbarium.
| A. Annual, dwarf, 1–3 in. high. Flowers solitary at the tips of the branches. Calyx-lobes broadly ovate. | |
| Stems simple or sparingly branched. Leaves mostly cauline, ⅙–⅓ in. long. Flowers ⅓ in. diam. | 1. G. filipes. |
| B. Perennial, dwarf, 1–4 in. high. Flowers solitary, terminating naked scapes. Calyx-lobes linear-subulate. | |
| Stems densely tufted. Leaves all radical, narrow-linear, ⅓–¾ in. Flowers ½ in. diam. | 2. G. lineata. |
| C. Annual, slender, 3–14 in. high. Leaves mostly cauline. Flowers ⅓–½ in. diam. Calyx-lobes linear-subulate. | |
| Stems weak, sparingly branched. Leaves oblong-spathulate, thin | 3. G. Grisebachii. |
