Dryadoideae
Dryas × suendermannii
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Rosales
Family:	Rosaceae
Subfamily:	Dryadoideae
Genera
Cercocarpus Kunth Chamaebatia Benth. Dryas L. Purshia DC. ex Poir. (including Cowania)

The Dryadoideae subfamily of the Rosaceae consists of four related genera^[1], all of which share root nodules that host the nitrogen-fixing bacterium Frankia^[2]. They are sub-shrubs, shrubs, or small trees with a base chromosome number of 9, whose fruits are either an achene or an aggregate of achenes^[1].

[edit] Notes

1. ^ ^{a b} Potter, D., et al. (2007). Phylogeny and classification of Rosaceae. Plant Systematics and Evolution. 266(1–2): 5–43.
2. ^ Swensen, S.M.; Mullin, B.C. (1997). The impact of molecular systematics on hypotheses for the evolution of root nodule symbioses and implications for expanding symbioses to new host plant genera. Plant and Soil. 194: 185–192.