udumbara; mythical Indian plant
In Buddhist legend, a plant said to bloom only once every 3000 years, often identified with the cluster fig (Ficus glomerata).
Buddhist scriptures record that the udumbara blooms once every 3000 years.
something extremely rare
Metaphorical use derived from the legend; refers to anything that is exceptionally rare or hard to encounter.
His talent is truly something as rare as the udumbara flower.
Japanese fiber banana flower
Refers to the flower of the Japanese fiber banana (Musa basjoo), also called バショウ. This usage is botanical and less common.
See also: バショウ
The Japanese fiber banana flower is also called udonge.
green lacewing eggs
The eggs of green lacewings (クサカゲロウ) are sometimes called 優曇華 because of their resemblance to the mythical flower. This is a specialized entomological term.
See also: クサカゲロウ
Green lacewing eggs are sometimes likened to udonge.
From the Sanskrit 'udumbara', via Buddhist texts. The kanji 優曇華 are ateji used phonetically to represent the sound.