A Grammatical Dictionary of Botanical Latin

-ior,-ius (adj.B): Latin comparative adjective endings added to the stem of the adjective (and also the participle), declined approximately like B adjectives (except in abl.sg. where the ending is -e, not -i);

PARTICIPLES: present active participles may also use the comparative forms of regular adjectives (see below):

              singular                       plural 
  Nom. (m/f)  -ior    (n.) -ius     (m/f)  -iores   (n.) -iora 
  Gen.           -ioris                        -iorum 
  Dat.           -iori                         -ioribus 
  Acc. (m/f)  -iorem  (n.) -ius     (m/f)  -iores   (n.) -iora 
  Abl.           -iore [NOTE]                  -ioribus

     I. ADJ.A.  (positive degree)     crassus,-a,-um (adj.A), ‘thick;’   < 
             (comparative degree)  crassior,-ius:  ‘thicker’ 
              singular                                plural 
  Nom. (m/f) crassior   (n.) crassius     (m/f)  crassiores   (n.) crassiora 
  Gen.           crassioris                          crassiorum 
  Dat.           crassiori                           crassioribus 
  Acc. (m/f) crassiorem (n.) crassius     (m/f)  crassiores   (n.) crassiora 
  Abl.           crassiore [NOTE                     crassioribus

NOTE: the neuter genitive plural, ‘crassiorum’ should not be confused with the genitive plural of the positive degree, which (in masc. and neut.) is also crassiorum.

foliorum crassiorum, of the thicker leaves, and foliorum crassiorum, of the thicker leaves, but in the positive it is crassi- + -orum.

in comparative it is crassior- + -um

     II. ADJ.B.  (positive degree)    humilis,-e, ‘low’   
             (comparative degree) humilior,-ius:  ‘lower’ 
               singular                              plural 
  Nom. (m/f) humilior   (n.) humilius     (m/f)  humiliores   (n.) humiliora 
  Gen.           humilioris                          humiliorum 
  Dat.           humiliori                           humilioribus 
  Acc. (m/f) humiliorem (n.) humilius     (m/f)  humiliores   (n.) humiliora 
  Abl.           humiliore                          humiloribus

NOTE: an alternative to this formation of the comparative adjective is to use the positive degree + the adverb ‘magis,’ = ‘more.’ This applies to adjective forms ending in -atus,-a,-um (adj.A) which may be part passive participles, but also simply the -atus ending + a noun:

NOTE: the adverb ‘minus’ = ‘less’ corresponds to this formulation:

- fila minus mucosa, the filaments less mucose.

- dissectus, dissected, is not dissectior, but adverb magis (more in degree) may be used: magis dissectus: squamis magis dissectis differt, it differs by the scales more dissected.

- foliolis magis multijugatis, with the leaflets more multijugate (in more multiple pairs).

- folia magis dentata et venosa (B&H), leaves more dentate and [with large veins].

- [alga] fila simplicia, capillaria, oculo nudo satis conspicua, post copulationem minus mucosa, magisque crispata (Agardh), [vegetative filaments] simple [i.e. undivided or branched], hair-like, quite conspicuous to the naked eye, after copulation, less mucose and more crisped.

- genus species australes continet, a borealibus nonnisi lobis foliorum magis intrusis distinguendas (B&H), the genus contains southern species, not to be distinguished from the northern except by the lobes of the leaves more pushed in [i.e. indented].

III. PARTICIPLES: present active participles may also use the comparative forms of regular adjectives:

- recens,-entis (new, fresh, young), compar. recentior,-ius (adj.B) superl. recentissimus,-a,-um (adj.A).

- prominens,-entis (part.B), prominent, standing or jutting out; compar. priminentior,-ius (adj.B) [> L. promineo,-minui, 2. to stand out, jut out].

- constans,-antis (part.B), firm, constant: compar. constantior,-ius (adj.B), superl. constantissimus,-a,-um (adj.A).