A Grammatical Dictionary of Botanical Latin

f. sp. (abbrev.), plural ff. spp.: (in fungi) forma,-ae (s.f.I) specialis (adj.B), abl.sg. forma speciali, ‘special form,’ plural: formae speciales, gen.pl. formarum specialium: an informal taxonomic designation not covered by the Code of Nomenclature to distinguish morphological or physiological forms within other taxa, such as species or varieties: Puccinia graminis f.sp. phleipratensis; also P. graminis f. sp. Avenae,[the Puccinia of grass, ‘special form of oats]. The forma specialis is an infraspecific name.

Eng. “known as formae speciales” (special forms).

f.sp.,“forma specialis’ Latin epithets may be simple adjectives in the nom.sg. or in the gen.sg., especially in reference to the genus of the host.

1. adj. nom.sg. modifying neuter generic noun Fusarium: Fusarium oxysporum f.sp. cubense (dwelling in Cuba)

f.sp. niveum (snow white)

2. gen.sg.: noun of the host genus:

Fusarium oxysporum f.sp. asparagi (of Asparagus)

f.sp. Callistephi (of Callistephus)

f.sp. Dianthi (of Dianthus)

f.sp. lycopersici (of Lycopersicon)

f.sp. melonis (of Melon)

f.sp. pisi (of Pisum)