Morphological observation on the inflorescence development of Tridax procumbens, Eclipta prostrata, Eleutheranthera ruderalis, Synedrella nodiflora (Asteraceae, Heliantheae)

Abstract

Asteraceae is one of the cosmopolitan flowering plants spread in various regions, including Indonesia. Tridax procumbens, Eclipta prostrata, Eleutheranthera ruderalis, and Synedrella nodiflora are commonly found at Universitas Indonesia Campus, Depok. The research was conducted to describe the development stages of flowers and fruit forms from the four species of the Heliantheae tribe. Samples were taken by purposive sampling technique at several locations at Universitas Indonesia Campus, Depok. All stages of flower buds start from the smallest until the dry up fruit stages are collected and observed using the Dinolite device and the Dino capture 2.0 application. The results showed that there were variations in the number of stages of inflorescence-fruit development in the four species observed, with a range 9-16 stages. The flowering stage divided into four groups, namely pre-anthesis, beginning of anthesis, anthesis, and senescence. In the pre-anthesis stage, the inflorescence is still in the bud form and green; at the beginning of anthesis, the buds begin to open, and the corolla begins to appear; the anthesis stage is marked with a fully open corolla; while the senescence stage is characterized by a change in the corolla into brown and dries out. The four species observed have achene (cypsela) fruit with sizes ranging from 3-4 mm. The fruits have Achene (cypsela) with pronounce and a reduced part of distribution accessories. Seed distribution accessories are winged peripheral, lanceolate shaped central, capillary bristle, and reduced pappus.