Hypericum gramineum
Perennial or annual herb (0.025-)0.05-0.72 m tall, erect or decumbent but not rooting, branching strictly from the base or unbranched, occasionally with strict or ascending lateral branches, sometimes naked below. Stems green, persistently 4-lined, ancipitous when young, cortex persistent or rarely deciduous in strips; internodes 3-33(-55) mm long, those in the upper 1/3- 2/5 exceeding the leaves. Leaves sessile, spreading to appressed, 4-25 x 1.2-8 mm, lanceolate to linear or oblong or rarely ovate-lanceolate, margin plane or recurved, paler and glaucous beneath, chartaceous; apex obtuse to rounded, base cordate to rounded or sometimes cuneate, amplexicaul and usually somewhat decurrent, then forming shallow V, free; basal veins 1-3, midrib sometimes with up to 5 obscure branches, tertiary reticulum not evident; laminar glands small and dense above, larger and laxer beneath, not prominent. Inflorescence (l-2)3-c.30-flowered, dichasial/ monochasial or pseudo-dichotomous or mixed, without accessory branches, sometimes with lateral branches from up to 3 nodes below, the whole laxly obconic to narrowly ellipsoid; primary pedicels 2-17 mm long; bracts and bracteoles triangular-lanceolate to linear. Flowers 5-12(-15) mm in diam., stellate; buds ellipsoid, subacute. Sepals 2.8-7.5(-9) x 0.8-2 mm, subequal to unequal, imbricate, lanceolate to narrowly elliptic or oblong-elliptic, acute to subacute (or rarely rounded - hybrids?); veins 3-5, only midrib sometimes prominent; glands linear, distally punctiform. Petals pale to bright yellow or orange, 5-10 x 2-5 mm, c. 1-3 x sepals, obovate to oblanceolate; apiculus obtuse to rounded; glands few, striiform, or absent. Stamens c. 20-50, irregular, longest 2.5-4 mm long, 0.4-0.6 x petals. Ovary 1.5-2.3 x 0.6-1.2 mm, narrowly ovoid-conic; styles 3, 0.7-1.8 mm, long, 0.5- 0.9 x ovary, spreading; stigmas broadly to narrowly clavate. Capsule 2.5-8 x l-3.5(-4) mm, narrowly ovoid to cylindric, 0.8-1.2 x sepals. Seeds 0.5 mm long, not carinate; testa finely ribbed-scalariform.
2n = 16 (n = 8), 14, see Robson & Adams (1968).
Open grassy or shrubby habitats, dry or wet but well drained; 0-1050 m (Australia, New Zealand, New Caledonia, Viet-nam, Taiwan), 10-2250 m (New Guinea), 1500-3000 m (China (Yunnan), India (Assam), Bhutan).
New Zealand, Australia, New Caledonia, New Guinea (Papua-New Guinea), Vietnam, Taiwan, China (Hainan, Yunnan), India (Meghalaya, Manipur), Bhutan, Hawaii.
H. gramineum, despite its Old World distribution, is most closely related to the Paraguayan form of H. carinatum sensu stricto (i.e. not 'H. altissimum') and to the Chilean (primitive) form of H. silenoides ('H. paposum'). From H. carinatum it differs inter alia by the trimerous ovary and consequent narrower capsule and by all parts being smaller and narrower. It differs from H. silenoides in having leaves thicker, glaucous, and often appressed, with 1-3 basal veins (not (3)5-9) and no evident tertiary reticulate venation, pedicels up to 17 mm long, larger (particularly broader) petals, usually more numerous stamens (20-50, not (9)14- 32), and clavate not capitate stigmas.
H. gramineum is very variable, the largest forms (morphologically nearest to its S. American relatives) being in south- eastern Australia and New Zealand. In Australia there are reduction trends north and west, to Queensland and Northern Territory on the one hand and Western Australia on the other, to less strict, more branching forms smaller in all their parts. The New Zealand trend is continued to New Caledonia and New Guinea, where laxer, less strict, more grass-like forms occur (hence the specific epithet). The lowland form of Vietnam and Taiwan is like the laxer type of Queensland and Northern Territory, whereas the upland (Himalayan and Khasian) form is strict and more similar to the New Zealand and south-eastern Australian type. The Hawaiian plants are also strict.
It is tempting to suggest that the trans-South-Pacific links of H. gramineum indicate that it once had an Antarctic type of distribution. This, however, seems most unlikely for two main reasons:
i) The genus does not now occur on the western side of S. America south of central Chile (H. caespitosum Cham. & Schlechtendal).
ii) As Hypericum appears to have originated in Africa and to have spread overland westwards to S. America, by the time the ancestors of H. gramineum reached the west coast, the land-links with Antarctica (and Australasia?) would have long been broken. Hence the most likely hypothesis is that the progenitor of H. gramineum reached south-east Australasia by ancient long-distance dispersal, to New Zealand and then to SE. Australia, or vice versa. The morphological facts already mentioned would then suggest that long-distance dispersal also carried the strict form to the eastern Himalaya and Hawaii from south-eastern Australia or New Zealand and the lax form to Vietnam, Hainan, and Taiwan. Alternatively, the Taiwan introduction could have been via New Guinea (see Robson, 1972: 267, f. 3).
The two Asiatic species of sect. Trigynobrathys, H. japonicum and H. gramineum, can nearly always be differentiated, but some Bhutanese specimens have apparently intermediate characters. It is not clear whether these are the result of convergence or hybridisation.
As a result of DNA sequencing studies, Heenan (2008) placed H. gramineum in a polychotomy that included H. japonicum sensu latissimo and H. mutilum sensu lato. The two samples of H. gramineum were distinct, suggesting that the New Zealand population might comprise two species.
I have treated Heenan’s two new species (H. minutiflorum and H. rubicundulum) after H. japonicum as Spp.47-48. It could be that they would be better considered as relatives of H. gramineum.
Without my having seen the type of H. japonicum var. kainantense Masam., the identity of this taxon must remain uncertain. H. gramineum has, however, been recorded from Hainan by Rodriguez Jimenez (1973). The description ('Folia coriacea lineari-ovata . . . Sepala ovata ca. 5 mm longa ca. 2 mm lata, acuminata') agrees more with H. gramineum than with H. japonicum.