capitalization: biological terms

Capitalize the scientific name of a phylum, class, order, family or genus:

• the phylum Arthropoda
• the order Rosales
• the genus Sporotrichum

Do not capitalize common names or the epithets referring to a species or subspecies, even if they are derived from proper names:

• The jaguar and the lion are members of the family Felidae.
• the species Sporotrichum schenkii (second word denotes species)

Note: For rules governing the italicization of biological classifications, see italics: mathematical and scientific material.

Also, capitalize proper nouns modifying a common name, except where usage has established the lower case:

• Grayson lily
• Cupid’s-delight
• Queen Anne’s lace
• Judas tree
• Canada goose
• Dutch elm

but

• timothy grass