Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
rŭbesco, bŭi, 3, v. inch. n. [rubeo], to grow red, turn red, to redden (poet. and in post-Aug. prose): Aurora, Verg. A. 3, 521; Ov. M. 3, 600: mare radiis, Verg. A. 7, 25: matutina tempora, Ov. M. 13, 581: terrae mundusque, id. ib. 2, 116: saxa sanguine vatis, id. ib. 11, 19: arva novā Neptunia caede, Verg. A. 8, 695: genae, blush, Ov. M. 7, 78: Pompeius numquam non coram pluribus rubuit, Sen. Ep. 11, 3: rosa, Plin. 21, 4, 10, § 14: vina, id. 14, 2, 4, § 35 (Jahn, rufescentia): dentes, id. 11, 37, 63, § 167 (Jahn, rufescunt).