Description from Flora of China
Trees, deciduous, usually more than 10 m tall, sometimes to 30 m. Leaves 15-40 cm; leaflets 5-12 pairs, 2-8 × 1.2-3.3 cm, both surfaces pilose or abaxially pilose, adaxially sparsely puberulent, base slightly asymmetric, apex acute, obtuse, or shortly acuminate. Inflorescences lateral on short side branches or terminal on young leafy shoots. Sepals ovate or broadly lanceolate. Petals deep yellow or pink, 2.5-4.5 × 1-2 cm. Stamens 10, among them 3 abaxial antesepalous with filaments longer than other 7. Ovary pubescent. Legume terete, 30-50 × 0.2-1.5 cm, with annular nodes.
This is a very polymorphic species with a wide distribution from N India through the Indochinese Peninsula and the Malesian region to New Guinea. Altogether, seven subspecies are recognized, two of them in China. Outside of China, Cassia javanica subsp. javanica was described from Java, is widely distributed from Indonesia to the Philippines, and is widely cultivated as an ornamental throughout SE Asia. The other four subspecies are subsp. bartonii (F. M. Bailey) K. Larsen (New Guinea); subsp. microcalyx (H. S. Irwin & Barneby) K. Larsen (Indonesia: Kalimantan and Sumatra); subsp. pubiflora (Merrill) K. Larsen (Philippines); and subsp. renigera (Wallich ex Bentham) K. Larsen (Myanmar).
Forests, mountain slopes, also cultivated. Native in Guangxi and Yunnan; cultivated in S China [India, Indonesia, Laos, Malaysia, Myanmar, New Guinea, Philippines, Thailand, Vietnam; widely cultivated in the tropics].