Tie Shu Ye

Cycas revoluta, the sago cycad or 'king sago palm', is not a true palm but a gymnosperm of the ancient Cycadaceae, native to southern Japan (notably Kyushu and the Ryukyus) and southeastern China and widely cultivated as an ornamental. It grows extremely slowly to 2–3 m, forming a stout, columnar, persistent-leaf-base-clothed trunk crowned by a symmetrical rosette of stiff, dark green, pinnate fronds 60–150 cm long. The narrow, leathery pinnae are sharply pointed, with strongly revolute margins — the source of the specific epithet. The species is dioecious: male cones are large, narrow, yellow, and pollen-bearing; female plants produce a low, rounded dome of woolly megasporophylls bearing bright orange seeds. The medicinal organ is the dried leaf (pinna), cut from mature fronds. All parts contain the toxins cycasin, methylazoxymethanol, and BMAA.