Apocynaceae

(L.) R.Br. ex Roem. & Schult.

Bhutan2014 64
Bhutan Trashigang 1250m, May
Bhutan2012 732
Bhutan Galephu 550m, October
Bhutan2012 736
Bhutan Galephu 550m, October

Description

Tabernaemontana divaricata is a shrub of tropical and subtropical Asia, native to the Indian subcontinent and Southeast Asia and now pantropically cultivated and naturalised; GBIF records over 6500 occurrences across countries including India, China, Thailand, Sri Lanka, Bangladesh, Malaysia, Vietnam, the Philippines and many introduced ranges in the Americas and Pacific. In Bhutan it was photographed at Trashigang at 1250 m in May and at Galephu at 550 m in October, reflecting its occurrence in warm foothill forests, scrub and village surrounds, where it is also widely planted as the ornamental "crape jasmine."

It is a glabrous, evergreen shrub with dichotomously branched (divaricate) stems exuding copious white latex when cut. The leaves are opposite, simple, elliptic to oblanceolate, glossy dark green, with a tapering apex and prominent lateral venation. The flowers are borne in few-flowered terminal or axillary cymes; each is salverform with a slender tube and five contorted, white, often pinwheel-twisted lobes, fragrant especially at night, and cultivated double-flowered forms are common. The fruit is a paired (often divaricate) follicle, somewhat curved and ridged, splitting to expose seeds embedded in a bright orange-red fleshy aril.

The species belongs to the Apocynaceae (subfamily Rauvolfioideae) and, like its relatives, is rich in indole and monoterpene alkaloids that underpin its use in traditional medicine and account for its toxicity. Long cultivated, it has accumulated many synonyms and horticultural forms. It is not threatened, being abundant in cultivation and naturalising readily; its presence in lowland Bhutan marks the subtropical Himalayan margin of a broadly Indomalayan range.

Author: (L.) R.Br. ex Roem. & Schult. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Flora of British India, revision of Tabernaemontana (Leeuwenberg)

(Roth) Kuntze

Bhutan2014 231 1
Bhutan Karu-Chu 1800m, May
Bhutan2014 234
Bhutan Karu-Chu 1800m, May
Nepal 97 28 P45
Nepal Dhoban 735m April

Description

Vallaris solanacea is a woody climber of tropical and subtropical Asia, broadly distributed from the Indian subcontinent and the Himalayan foothills through Indochina, southern China and the Malesian region (gbif_countries: IN, TH, CN, NP, MM, US, ZZ, LK, MY, GP, KH, LA, BD, BT, VN, ID, PK, SC), with GBIF documenting some 536 occurrences. It grows in lowland and submontane forests, thickets, riverine scrub and forest margins, often scrambling over shrubs and small trees. The illustrated gatherings range from Dhoban in Nepal at about 735 m, flowering in April, up to Karu-Chu in Bhutan near 1800 m in May, reflecting its preference for warm, humid lower hill country.

The plant is a glabrous to finely pubescent liana with milky latex and opposite, elliptic to ovate leaves that are entire, pinnately veined and shortly petiolate. The flowers are borne in axillary or terminal cymes and are fragrant, with a white, rotate to broadly campanulate corolla bearing five spreading lobes, the throat marked with hairy appendages; the floral form recalls a Solanum, the resemblance enshrined in the epithet. The androecium consists of five stamens with connivent anthers adhering to the stigmatic head, and the fruit is a pair of slender, spreading follicles releasing comose seeds adapted to wind dispersal.

A member of subfamily Apocynoideae, Vallaris is a small Indomalayan genus of latex-bearing twiners. V. solanacea is locally valued as an ornamental for its sweetly scented blossoms and is used in traditional medicine, while its latex and tissues, like those of many Apocynaceae, contain bioactive compounds. Widespread and adaptable, it is of no conservation concern across its extensive range.

Author: (Roth) Kuntze · Sources: POWO (Kew), GBIF, Flora of Nepal, Flora of China, Flora of British India, Flora Malesiana account of Apocynaceae

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