PlantaeDB Logo
Login Sign-up

Genus Pycnarrhena in Family Menispermaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

The genus Pycnarrhena (Miers ex Hook.f. & Thomson) lies in the early-diverging menispermaceae lineage and comprises about 17 species of climbers, with a center of diversity in New Guinea and a secondary focus in Borneo and northern Queensland; the species are distributed from Myanmar and Thailand through Malesia to northern Australia and the Solomon Islands, primarily in lowland rainforest and coastal forest up to c. 800 m elevation. The type species is Pycnarrhena lucida (Teijsm. & Binn.) Miers ex Hook.f. & Thomson; Forman, 1986 recognizes P. australiana (F.Muell.) Diels as the Australian representative.

Morphologically Pycnarrhena is diagnosed by its slender, often glabrous lianas with entire, simple leaves lacking the conspicuous stipules typical of many Menispermaceae; the flowers are small, unisexual, with three sepals and six petals, and six free stamens; the gynoecium is typically tricarpellary with two ovules per carpel, but only one usually matures, giving a solitary pendulous drupe with a strongly curved seed, the endocarp horseshoe-shaped and pitted. Vegetatively the plants are essentially glabrous and often have distinctly reticulate venation.

Intrinsic biology is incompletely documented; fleshy drupes imply endozoochorous dispersal likely by birds or bats, but specific agents are unrecorded; the reported base chromosome number of n=13 in P. australiana (Hekking, 1988) requires verification in additional taxa. The genus is not widely cultivated and lacks significance as a crop or timber, with no notable weeds reported.

Recent work has clarified boundaries: Forman (1986) treated several taxa previously placed in R大门 under Pycnarrhena, noting the overall uniformity of the unisexual, hexandrous flowers and curved seeds; within the family Pycnarrhena has been resolved as nested within the Early Divergent Clade I of Menispermaceae in recent phylogenies (Jacques et al., 2011; Wang et al., 2020), and the APG Updates align its placement to this broad circumscription (APG IV, 2016). Conservation outlook remains unclear due to a lack of Red List assessments and uneven taxonomic coverage across its range; the heavy pressure on lowland rainforest suggests potential vulnerability, and targeted surveys are needed to refine species limits and extinction risk.

Pick a Species to see its components: