Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
clāvŭla (clābŭla or clāvŏla), ae, f. dim. [clava], a scion, graft, Varr. R. R, 1, 40, 4; cf. Non. p. 414, 29.
clāvŭlus, i, m. dim. [clavus].