Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ĕchīnātus, a, um, adj. [echinus, a hedge-hog], set with prickles, prickly: calyx, Plin. 15, 23, 25, § 92: capitula echinata spinis, id. 27, 9, 47, § 71: folia, id. 22, 9, 11, § 24.