§231. Roots and Stems
A root used as a stem may appear—
a. With a short vowel: as, duc-is ( dux), DUC; nec-is ( nex); i-s, i-d. So in verbs: as, es-t, fer-t (cf. § 174. 2).
b. With a long vowel1: as, lūc-is ( lūx), LUC; pāc-is ( pāx). So in verbs: dūc-ō, ī-s for †eis, from eō, īre; fātur from fārī.
c. With reduplication: as, fur-fur, mar-mor, mur-mur. So in verbs: as, gi-gnō (root GEN), si-stō (root STA).
J. H. Allen and J. B. Greenough, New Latin Grammar (Boston: Ginn, 1903). Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities.