We present a novel account of root suppletion in comparatives and superlatives, and show how it accounts for the presence of ABB and ABC patterns, as well as the absence of ABA patterns. The account assumes that suppletive roots, despite appearances to the contrary, are not contextual allomorphs, but portmanteaus spelling out two distinct features, one belonging to the lexical root, and another one belonging to the comparative. The regular comparative affix then spells out an additional feature relating to the comparative domain. In other words, we show that the comparative (CMPR) head that enters into the morphological makeup of the comparative (Bobaljik 2012) is to be split up into two distinct heads, C1 and C2 (see also Caha 2016). We extend this idea to SPRL, which we show is likewise to be split up into S1 and S2, in order to account for suppletive ABC patterns. These four distinct heads receive empirical support from facts of the degree morphology in Czech and Latin. The new account of root suppletion allows a straightforward way of deriving the attested and unattested patterns of (root) suppletion in degree comparison. The analysis developed supports the hypothesis that the absence of AAB patterns in degree comparison is due to a constraint of a different nature altogether. This article is part of the special collection: *ABA