Notothixos

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Notothixos

Description

Aerial stem-parasitic shrubs, densely velvety tomentose on young parts. Leaves opposite, petiolate, entire, bifacial, curvinerved, usually with 3 or 5 veins visible on the upper surface. Inflorescences terminal, of 1 or more fan-shaped cymules, these solitary or in a racemose or spicate arrangement; cymules with 3-13 flowers developing successively from the centre outwards, with the central flowers male and the lateral flowers female; bracts small, triangular, in pairs subtending each cymule. Fruit narrowly ellipsoid to almost globose, crowned by the persistent tepals.

Distribution

Asia-Tropical:, New Guinea present from Sri Lanka eastwards and southwards to eastern Australia and the Santa Cruz Islands: present
Eight species distributed from Sri Lanka eastwards and southwards to eastern Australia and the Santa Cruz Islands. In Malesia 6 species, with a centre of diversity in New Guinea.

Morphology

All species of Notothixos have a dense, copious indumentum on the young parts, usually persisting at least on the leaf undersides, inflorescences and flowers. This easily distinguishes the genus from Viscum, in which all species are glabrous. The tomentum is creamy white to brown, often golden, and comprises mixed unicellular and multicellular hairs. The unicellular hairs are stellate, sometimes dilated into peltate scales. The multicellular hairs are dendritic, consisting of several to many stellate cells in series. For discussion and illustration see .

The basic inflorescence unit is a small cymose cluster subtended by a pair of small bracts. It becomes fan-like as successive flowers develop laterally. In some species the inflorescence is a single terminal cymule, but in others it is expanded in racemose or spicate fashion, usually with decussate pairs of cymules. In some cases these complex inflorescences are determinate, producing a terminal cymule, and in other cases are indeterminate. For discussion and illustration see .

Taxonomy

For a revision of the genus and discussion of relationships and biogeo- graphy, see .