Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
gummōsus, a, um, adj. [gummi], full of gum, gummy: folia, Plin. 22, 9, 11, § 24; 16, 38, 72, § 181 al. (in these passages the better reading is cumminosus).