What is the proper formatting for taxonomic scientific names in type written texts?

According to the AMA Manual of Style (10th edition), §22.5.4:

"[Use italics] for genus and species names of some microorganisms, plants, and animals when used in the singular and the names of a variety of subspecies. Plurals, adjectival forms, taxa bove genus (eg, class, order, family) are not italicized (see also 15.14, Nomenclature, Organisms and Pathogens):

BacillaceaeStaphylococcus aureusStaphylococcusstaphylococci"

§15.14.1 says:

"According to the international codes, initial capitals are used for all taxa, except for the second portion of the binomial. (That portion called the specific name in the zoological code and the specific epithet in the botanical and bacteriological codes.) Italics are always used for the genus and species components of the binomial. Diacritical marks (accents) and ligatures (eg, æ) are not used. Hyphens occassionally may be used in the specific epithet, eg, the butterfly Polygonia c-album, which has a c-shaped wing mark.

"All codes capitalize scientific names of taxa but differ on italicizing higher taxa. The bacterial code reocmmends italicizing all scientifi names but recognizes that journals may wish to style all organism names similarly. In JAMA and the Archives Journals, taxa bove genus are not italicized."

A table follows the text above (not reproduced here). This is but a brief excerpt from that section. The entire manual is listed in the related links.