Accepted name: Rheum ×rhabarbarum
Robust perennial. Leaves 5-veined, hairless above but with hairs on veins below. Leaf stalks not ridged but with a slight channel along the inner face. Flowers in branched clusters to 1.5 m tall on faintly ridged stems; late spring to early summer. Fruit an ovate nut. [R. rhabarbarum L. misapplied]
This is the common garden rhubarb that has been cultivated for about two centuries for the edible leaf stalks, eaten stewed, made into jams or sometimes used for wine.
The hybrid origin of rhubarb is complex. Certainly one of the parents is the E Asian R. rhabarbarum L. under which name this plant is often incorrectly listed, but there are probably several other species involved.
Commercial edible cultivars include 'Champagne', 'Giant Red', 'Sydney Crimson', 'Topp's Winter', 'Wilson's Ruby' and 'Everbearing Ruby'.
R. australe D. Don, Red-veined Pie Plant from the Himalaya is occasionally offered; it has ovate to circular leaves which are hairy on both surfaces.
Source: (1997). Polygonaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.