Family: Ranunculaceae (Buttercup family).
Occurrence: It mostly grows submerged in rivers or creeks. Records are from Metcalfe-Redesdale area.
This buttercup was originally identified (from a specimen at Metcalfe) as Ranunculus rivularis, now R. amphitrichus, the Small River-buttercup. Small River-buttercup is widespread south of the Divide, and its presence locally would seem to be anomalous.The flower size, and leaf size seem too large, and closer to R. inundatus, the River Buttercup.
Buttercup petals have a nectary at the base. The nectary secretes nectar, and may be a narrow bracket or a deep pocket. The nectary is a distinguishing feature for the River Buttercups.
R. amphitrichus: Nectary lacks a lobe, and appears as a crescentic bracket.
R. inundatus: Nectary a distinct lobe, the lateral margins partly or wholly fuses to the petal, forming a narrow pocket