Loranthus

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Loranthus

Description

Aerial stem-parasitic shrubs, sometimes with epicortical runners bearing secondary haustoria. Leaves opposite or displaced. Inflorescences a simple spike; bracts single under each flower. Flowers probably mostly functionally unisexual but usually with organs of the other gender present, either apparently normally developed or vestigial. Fruit nearly globular.

Distribution

Asia-Tropical:, Sulawesi (Sulawesipresent); Sumatera (Sumaterapresent) from southeastern Europe to southern Asia as far as Japan: present
Probably 2 species, from southeastern Europe to southern Asia as far as Japan. In Malesia 1 species, known from Sumatra and Celebes.

Taxonomy

In this genus several species have been distinguished on the basis of number of petals, and on plants being apparently dioecious or hermaphrodite. These variations have little systematic value; see The two species now accepted have robust differences in inflorescence insertion and structure.
Loranthus is very closely related to the larger genus Helixanthera, which extends from Africa to southern Asia and northwestern Malesia. Helixanthera is relatively polymorphic, with a few species groups which differ strikingly from each other in flower size, relative style length and presence or absence of an articulation in the style. It is difficult to discriminate Loranthus as an entity with differences greater than those which distinguish the groups within Helixanthera. The presence of unisexual flowers has sometimes been used to distinguish Loranthus, but the character appears to be variable even within the species of the genus. Danser accordingly expressed the view that Loranthus (Hyphear) and Helixanthera are congeneric. Further study is needed to resolve this issue, as the taxonomic consequence of uniting the genera would be the submergence of the larger genus Helixanthera into the very small genus Loranthus. For further discussion, see . , has without discussion apparently proposed union of these two genera. However, he has overlooked the nomenclatural conservation of Loranthus, and has accordingly placed Hyphear (1929) in synonymy under Helixanthera (1790).

Notes

The originally designated type species of Loranthus, L. americanus, is referable to the large American genus Psittacanthus. The usual application of the name Loranthus has been restored by conservation, with the well-known L. europaeus nominated as type; the usual application of the name Psittacanthus is accordingly also retained.