Hypericum balearicum (Nomenclature)
Shrub or small tree 0-6--2 m tall, usually forming rounded bushes, with branches erect to ascending, sometimes branching pseudo-dichotomously. Stems yellow-green when young, glandular-verrucose, especially along the (4) stem lines, terete after first season; internodes 2-10 mm long, shorter than leaves; bark reddish-brown. Leaves sessile; lamina (6--)8--15 x 3-7 mm, ovate to oblong-elliptic or narrowly oblong, rounded, margin ± undulate, base broadly cuneate to rounded, paler beneath, not glaucous, coriaceous, lower ones gradually deciduous; venation: 1 basal vein (midrib), 1 pair of main laterals (intramarginal vein) and c. 5 subsidiary laterals (cross veins) joining intramarginal vein, with or apparently without obscure tertiary reticulum; laminar glands large, vesicular, prominent, amber, often interspersed with ± numerous small pale dots (beneath); marginal glands dense. Inflorescence 1-flowered; pedicel 3-11 mm long; bracts sepaline, involucral. Flowers 15-40 mm in diam., stellate; buds ovoid-subglobose, obtuse to rounded. Sepals 5-7 x 2-5 mm, imbricate, ± unequal, erect in bud, ± reflexed in fruit, rounded, margin entire to apically denticulate, midrib undifferentiated or obscure; laminar glands linear, interrupted distally, numerous, sometimes also 1-4 large amber vesicular; marginal glands absent. Petals golden yellow or very rarely pale yellow, slightly red-tinged outside, deciduous, spreading, 10-20 x 4-9 mm, 2-3 x sepals, narrowly obovate to oblanceolate, with apiculus very small, rounded or absent; margin entire; laminar glands linear, sometimes interrupted distally. Stamen fascicles deciduous, each with 18-25 stamens, longest 8-18 mm long, c. 0-8 x petals, with filaments very shortly united. Ovary 3-5 x 2-3 mm, narrowly ovoid-conic; styles 6-13 mm long, 2-2.5 x ovary, suberect or slightly outcurved distally; stigmas small. Capsule 8-12 x 5-7 mm, narrowly ovoid to ovoid-pyramidal. Seeds reddish-brown, c. 1-7 mm long, cylindric, not carinate or winged, finely linear-reticulate.
2n = 24 (see Castro & Rosselló (2007).
Dry woods and calcareous rocky or stony places; 30-1200 m.
Balearic Islands (Mallorca, Menorca, Ibiza, Cabrera, Dragonera).
The glandular-verrucose stems and leaves and the involucre-like bracteoles distinguish H. balearicum from all other species of Hypericum. It has such an isolated position in the genus that its affinities are not immediately obvious. The leaf-venation and floral characters, however, indicate that H. revolutum subsp. revolutum is its closest relative, in particular the broader-leaved form of that species that occurs in Ethiopia.
H. balearicum is apparently confined to the Balearic Islands, where it is quite common on Mallorca but rare on the other islands on which it occurs. The Italian locality cited by some authors (Liguria, Appenines above Savona) is the result of introduction (see Knoche, loc. cit.). H. balearicum has been discussed in detail by Contandriopoulos & Cardona (1984). For a detailed account of the chromosomes, see Castro & Rosselló (2007). See Part 9, Bibliography for both references.
The Herb. Linn. specimen of Hypericum balearicum L. is chosen in preference as lectotype to that in Herb. Cliff, on account of the new diagnosis provided in Sp. pl.: Hypericum floribus pentagynis, caule fruticoso, foliis ramisque cicatrisatis.