Hypericum

Hypericum olympicum, photographed by Michael Kesl.


Belongs within: Clusiaceae.

Hypericum, the St John's worts, is a cosmopolitan genus of yellow-flowered plants, varying from herbs to small trees. The common St John's wort Hypericum perforatum has been used pharmaceutically.

Characters (from Li & Robson): Shrubs, subshrubs, or perennial herbs (rarely trees), glabrous or with simple hairs, with translucent ("pale") and often opaque, black or reddish ("dark") glands, laminar (immersed and sometimes abaxial) and marginal or intramarginal. Leaves opposite (occasionally whorled), sessile or short petiolate, venation pinnate to palmate (or rarely dichotomous), margin entire or gland-fringed. Inflorescence cymose. Flowers bisexual, homostylous (occasionally heterostylous), stellate or cupped. Sepals 5 and quincuncial or rarely 4 and decussate, unequal or equal, free or partly united. Petals (4 or)5, contorted, golden to lemon yellow (or rarely white), abaxially sometimes tinged or veined red, persistent or deciduous after anthesis, usually asymmetric. Stamens in (4 or) 5 fascicles, free and antipetalous, or some united to form apparently 4 or 3 fascicles with compound fascicle(s) antisepalous, or irregular and apparently not fasciculate, persistent or deciduous, each single fascicle with up to 70(-120) stamens; filaments slender, free from nearly base (occasionally to 2/3 united) or apparently completely free; anthers small, dorsifixed or ± basifixed, dehiscing longitudinally, with gland on connective; sterile fascicles (fasciclodes) absent [very rare]. Ovary 3-5-loculed with axile placentae or ± completely 1-loculed with (2 or)3(-5) parietal placentae, each placenta with (2 or) few to many ovules; styles (2 or)3-5, free or partly to completely united, more or less slender; stigmas small or more or less capitate. Fruit a septicidal capsule or rarely ± indehiscent, valves often with oil-containing vittae or vesicles. Seeds small, often carinate or narrowly unilaterally winged; testa variously sculptured, not arillate (very rarely carunculate); embryo slender, straight, with distinct slender cotyledons.

<==Hypericum
    |--H. androsemum JK80
    |--H. beanii CB01
    |--H. calycinum CB01
    |--H. canariense CB01
    |--H. fuertesii J87
    |--H. gramineum CB01
    |--H. hidcote CB01
    |--H. hirsutum CB01
    |--H. hypericoides J87
    |--H. japonicum CB01
    |--H. kouytchense CB01
    |--H. millefolium J87
    |--H. monanthemum O88
    |--H. moserianum CB01
    |--H. olympicum CB01
    |--H. patulum CB01
    |--H. perforatum CB01
    |    |--H. p. var. perforatum CB01
    |    `--H. p. var. angustifolium CB01
    |--H. pulchrum CB01
    |--H. pusillum C45
    |--H. quadrangulum CB01
    |--H. quinquenervium C55b
    |--H. reptans CB01
    |--H. revolutum B06
    |--H. richeri C55a
    |--H. rowallene CB01
    |--H. russeggeri S54
    |--H. stellatum CB01
    `--H. tetrapterum CB01

*Type species of generic name indicated

REFERENCES

[B06] Burgoyne, P. M. 2006. Review: Plants of the Simen. A flora of the Simen Mountains and surroundings, northern Ethiopia. Bothalia 36 (2): 253.

[C55a] Candolle, A. de. 1855a. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 1. Librairie de Victor Masson: Paris.

[C55b] Candolle, A. de. 1855b. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[C45] Colenso, W. 1845. Memoranda of an excursion, made in the Northern Island of New Zealand, in the summer of 1841-2; intended as a contribution towards the natural productions of the New Zealand groupe: with particular reference to their botany (concluded). Tasmanian Journal of Natural Science 2: 241-308.

[CB01] Cullen, J. M., & D. T. Briese. 2001. Host plant susceptibility to eriophyid mites used for weed biological control. In Acarology: Proceedings of the 10th International Congress (R. B. Halliday, D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff, eds) pp. 342-348. CSIRO Publishing: Melbourne.

[JK80] John, J. & K.-P. Kolbe. 1980. The systematic position of the “Theales” from the viewpoint of serology. Biochemical Systematics and Ecology 8: 241-248.

[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum – Biological Sciences 32 (1): 1-136.

[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: An introductory note. In The Himalayan Plants vol. 1 (H. Ohba & S. B. Malla, eds) The University Museum, University of Tokyo, Bulletin 31: 19-46.

[S54] Seidenstücker, G. 1954. Cyphodema rubricum n. sp., eine neue Mirine aus Syrien (Ins. Hem. Het. Miridae). Senckenbergiana Biologica 35: 99-100.

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