Science magazines
- Morelet's Crocodile
- Morro Bay Kangaroo Rat
- Morro Manzanita
- Morro Shoulderband Snail
- Mount Graham Red Squirrel
- Mount Hermon June Beetle
- Mountain Golden Heather
- Mountain Sweet Pitcher-plant
- Munroidendron racemosum
- Munz's Onion
- Myrcia Paganii
- Myrtle's Silverspot Butterfly
- Na Pali Beach Hedyotis
- Na'ena'e (Dubautia herbstobatae)
- Na'ena'e (Dubautia latifolia)
- Na'ena'e (Dubautia pauciflorula)
- Na'ena'e (Dubautia plantaginea ssp. humilis)
- Nani Wai'ale'ale
- Nanu
- Napa Bluegrass