Lactarius Persoon: S. F. Gray
A Natural Arrangement of British Plants I: 623. 1821.

Principle characteristics of the genus Lactarius:

• Spore deposit white to cream to ochre
• Lamellae attached
• Fruiting bodies exuding a latex when cut or broken.
• Latex watery, milky, to brightly colored, sometimes staining flesh
• Spores with amyloid ornamentation
• Flesh with clusters of sphaerocysts

Keys and descriptions of the genus Lactarius:

• Illinois Mycological Society: Lactarius
• University of Michigan Herbarium Fungus Monographs: North American species of Lactarius by Hesler & Smith
• Methven, A.S. (1997). The Agaricales (Gilled Fungi) of California. 10. Russulaceae II. Lactarius. Mad River Press: Eureka, CA.
• Hesler, L.R. & Smith, A.H. (1979). North American Species of Lactarius. University of Michigan Press: Ann Arbor, MI.

Lactarius species known to occur in California:

1. Lactarius alnicola var. alnicola
2. Lactarius alpinus var. mitis
3. Lactarius argillaceifolius var. megacarpus
4. Lactarius aspideoides
5. Lactarius atrobadius
6. Lactarius caespitosus
7. Lactarius californiensis
8. Lactarius circellatus var. borealis
9. Lactarius controversus
10. Lactarius cocoseolens
11. Lactarius deliciosus
    1. var. areolatus
    2. var. deliciosus
    3. var. olivaceosordidus
    4. var. piceus
12. Lactarius desjardinii
13. Lactarius fallax
    1. var. concolor
    2. var. fallax
14. Lactarius glutigriseus
15. Lactarius hysginus var. americanus
16. Lactarius kaufmanii var kauffmanii
17. Lactarius luculentus var. laetus
18. Lactarius manzanitae
19. Lactarius necator
20. Lactarius occidentalis
21. Lactarius olivaceo-umbrinus
22. Lactarius pallescens var. pallescens
23. Lactarius pallidiolivaceus
24. Lactarius pseudomucidus
25. Lactarius pubescens
26. Lactarius representaneous
27. Lactarius resimus var. resimus
28. Lactarius riparius
29. Lactarius rubidus
30. Lactarius rubrilacteus
31. Lactarius rufulus
32. Lactarius rufus
33. Lactarius scrobiculatus
    1. var. canadensis
    2. var. montanus
    3. var. pubescens
34. Lactarius subflammeus
35. Lactarius substriatus
36. Lactarius subvillosus
37. Lactarius subviscidus
38. Lactarius thiersii
39. Lactarius torminosus var. nordmanensis
40. Lactarius uvidus var. montanus
41. Lactarius xanthogalactus