It’s blooming season for phantom orchids (Cephalanthera austiniae), a lovely denizen of mixed conifer forest. If you stop to admire some, be sure to give them a sniff–they have a mild but very sweet fragrance, reminiscent of vanilla.
The lack of chlorophyll indicates that these little beauties don’t photosynthesize. Instead they are “mycoheterotrophic”, meaning they absorb nutrients from mycorrhizal fungi, which in turn gain their nutrients from nearby trees. They have earned their ghostly designation – they can remain dormant for up to 17 years, and reproduce sparingly in the wild and not at all in cultivation. The patch that grows in this location appears most years, under an open redwood/Doug fir/pepperwood canopy. 
Flowers Of Marin 