Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
juncus, i, m., a rush. 
- I.  Lit.: murteta juncis circumvincire, Plaut. Rud. 3, 4, 27: palustres, Ov. M. 8, 336: acutā cuspide junci, id. ib. 4, 299.
- II.  A twig resembling a rush, Plin. 26, 8, 46, § 72.