Wei Zhi
J Syst Evol. 1985, 23(4): 275-292.
The genus Millettia Wight et Arn. contains about 200 species and is distributed mainly in the tropical and subtropical regions of Asia and Africa, only a small
proportion of species extending towards the northern and southeastern coast of Australia. About half of species are found in Asia, with the greatest concentration in the
area from the eastern Himalayas to the hills of Indo-China, i.e. the valleys Irrawaddy,
Salween and upper Mekong (Lan-tsang River). Then, there are much fewer species
occurring in central and southeastern China, Japan, Indo-China, Malaysia, Indonesia,
Philippines, India and Pakistan.
Twigs or stems of some Millettia species arc being used ethnopharmacologically as
drugs for oral preparations in China. They appear to possess a tendency of so-called
“carminative or stimulant” activities in many home-remedies, but most plants of this
genus are poisonous and have recommended as a source of insecticide or used by the
natives to stupefy fish. The scientific and common names of many species are puzzled
in a confused manner. In the present paper the author reports 35 species with 11 varieties from China, of which five species with four varieties are described as new, eight
species are new records to the Chinese flora.
Since Wight and Arnott established the genus in 1834, it has had a taxonomic history with so many errors and confusions. The major contribution to the taxonomy of
this genus was made by Dunn in 1912, who monographed the genus on a worldwide
scale and grouped all 138 species known by then into 15 sections based on morphological characters, while in the Chinese flora 6 sections and 14 species were recognized.
Dunn’s work is not very satisfactory because the relationships between sections and descriptions of species are disordered and confused. Unfortunately, there was little work
on this genus for almost seventy years.
Here the phylogenetic relationships among thirty-five species of Chinese Millettia
were investigated by using the Wagner’s method, and twenty-six characters were used
and assigned as primitive or specialized states. All taxa recognized ave considered as
Operational Taxonomic Units, to which linked are the character divergence values for
each. Then the mutual groupings between taxa are determined. The Wagner tree
resulted from above procedure indicats that the Millettia species in China belong to six
phylogenetic groups, which ate treated here as sections, i.e. Acinacicarpae, Macrospermae, Millettia, Corynecarpae, Brevistylae and Curvistylae. The section Acinacicarpae is
characterized by its tropical tree habit, axillary racemiferous panicle, scimitar-shaped
and flat pod, which is the widest in the upper part. The section Millettia includes those
species from erect shrubs to moderate-sized trees, and they are probably widely distributed in the mesophytic forests. The section Macrospermae has developed a type of
large tropical and subtropical liana, with distinctly turgid pod which may indicate a
specialized and isolated group of the genus. The following sections are characterized
by terminal and axillary panicled inflorescences, climbing or twining shrub habits. The
section Eurybotryae and section Curvistylae are the progressive groups which extend
northward into warm-temperate regions. And the section Corynecarpae seems to form
an intermediate form between the raceme and the panicle. Besides sectional relationships the species ars also recognized based on distinct combinations of morphological
characters, geographic ranges, and ecological characteristics. Among the species this
paper deals with 18 are endemic to China, and the rest are also found in northern India
and Indo-China.