According to V. H. Heywood (1993), I. Friis (1993), W. T. Wang & C. J. Chen (1995), Takhtajan (1996) genus Procris belong to tribe Lecantheae. The genus Procris have 3 species in the world, almost distribute in warm-temperate and tropical regions of the Old World. In Vietnam genus Procris also has 3 species (Procris frotescens Blume
Procris langbianensis Gagnep and Procris rhizantha Gagnep) distributed in many provinces as Laocai, Langson, Hanoi, Thanhhoa. Ninhbinh, Ninhthuan, Lamdong. Genus procris has some characteristics: Herbs perennial, subshrubs. Stems often succulent. Leaves apparently altemate, distichous
nanophylls often present, very small, opposite to developed leaves
stipules intrapetiolar, undivided
pinnately veined, base asymmetric, margin usually entire or serrulate
cystoliths linear. Inflorescences axillary, sometimes at leafless nodes, of unisexual flowers (plants monoecious or dioecious)
male glomerules in lax cymes
female capitula, subsessile. Male flowers: perianth lobes 4 or 5, segments often valvate
stamens 4 or 5
filaments inflexed in bud
rudimentary ovary globose or obovoid. Female flowers: perianth lobes 3 or 4, very small, boat-shaped, free or connate at base
staminodes absent. Ovary straight
stigma sessile, penicillate, soon disappearing. Achene ovoid or ellipsoid.