落葉喬木，樹皮灰白具有紋路，細枝幹有黑色刺，老枝則脫落。三出複葉，頂小葉寬卵形，長寬各約10～15公分，葉炳基部及小葉柄基部均具有腺體一對。總狀花序，春季4～5月時開出繁花似錦的花朵。花瓣蝶形，兩體雄蕊（9+1）。莢果念珠狀，莢果膨大，長約20公分；紅色的種子，呈長卵腎形，種臍明顯，長1.5公分。種子稍具毒性，誤食會造成頭暈或嘔吐。
刺桐分布於亞洲中國大陸東南、臺灣、日本琉球，以及印度、馬來西亞、波里尼西亞等氣候溫暖之地區。如早年（1744年）來臺擔任御史之六十七先生，其所著的「番社采風考」中描述著：「番無年歲，不辨四時，以刺桐花開為度。」可見刺桐花在當時成了平埔族重要的季節指標。臺灣島上的平埔族人、卑南族人、阿美族人、排灣族人，亦或是居住在蘭嶼島上的雅美族人，也都是以刺桐開花的季節做為各族工作曆的指標；刺桐與臺灣原住民有著極為密切之關係。
臺2003年刺桐釉小蜂（Quadrastichus erythrinae）入侵臺灣，對刺桐造成極嚴重之危害，臺11公路沿線及本處栽培者亦然。主要是雌蟲產卵注入新生嫩芽或葉片，造成組織的異常增生，進而形成蟲癭，影響葉子生長與養份之製造，整體情況讓樹勢轉弱或死亡。在前述世界分布生長地區，都深受此蟲嚴重危害與滅種憂慮之困擾。本處最初摘種有45棵，陸續死亡，在林試所協助下，此刻尚保有9棵。
India coral tree is a thorny deciduous tree, where its bark is patterned with light grey stripes. Its leaves are pinnate, with each leaflet growing up to 10-15cm in both length and width. Its crimson flowers blossom in dense clusters during April to May, and its seed pods can grow up to 20cm in length. The seeds itself are red and are usually 1.5cm in diameter. Slightly toxic, eating can cause dizziness or vomiting.
This tree is distributed across tropical regions of Southeast Asia, including Taiwan, Ryukyu Islands of Japan, India, Malaysia and Polynesia. Most of the aboriginals in Taiwan marks its blossom time as the beginning of the farming season. Though, the India coral tree is often valued as an ornamental tree.
In 2003, the Erythrina gall wasp (Quadrastichus erythrinae) was introduced in Taiwan. It quickly became an invasive species that swiftly killed off most of the India coral trees along provincial highway 11. The wasp would lay their eggs into the tree saplings or leaves, which will then feed off and disrupt the growth of the tree.