Pigeonberry (Rivina humilis)
Rivina tinctoria,   Rivina humilis var. aurantiaca
This plant is native to the southern United States,and can be found as far north as Oklahoma.   It has an upright habit and can grow between 50 and 100cm in height.   The base of the stem sometimes becomes woody.
At the end of the Meiji Era, many plants were brought to the Ogasawara Islands from abroad.   The Pigeonberry is a naturalized plant which accompanied those who come to the Islands.
The flower is small and about 3mm in diameter and is white or pink tinged white.   This plant often has berries and flowers at the same time.   This flower has no petals, but its sepals look like petals.   We could miss the flower, but in the photos, 4 stamens and the swelling pistil are observed in the center of the near-translucent white flower.   At the beginning, the berry is white and ripens to pure red.
In Higashiyama Botanical Garden, in addition to Pigeonberry (Rivina humilis) its variations or relatives, Rivina humilis var. aurantiaca and Rivina tinctoria are planted as the Rivina genus.   Pigeonberry (Rivina humilis) has red berries and non-hairy leaves, but Rivina humilis var. aurantiaca has orange berries and hairy leaves.   Rivina tinctoria has red berries and hairy leaves.
The fruits of Pigeonberry and its relatives contain betalains.   Betalains do not coexist with anthocyanin and are specifically contained in the plants belonging to the order, Caryophyllales except in the families, Caryophyllaceae, Plumbaginaceae and Molluginaceae.   In the structure, betalains classify into reddish purple betacyanins and yellow betaxanthins.   Red or orange betalain does not exist but both colours mix to develop red or yellow.
Classification Phytolaccaceae Rivina
Scientific name Rivina humilis
Japanese name Juzu-sango
English name Pigeonberry, Rougeplant
Native locality Southern North America
Ecological description Evergreen perennial (subshrub)
RDB ---
Planting place Sun Gallery
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Rivina humilis
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Rivina humilis
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Rivina humilis
 
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Rivina humilis var. aurantiaca
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Rivina humilis var. aurantiaca
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Rivina tinctoria
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Rivina tinctoria
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Rivina tinctoria