Hydrophylloideae is a subfamily of the plant family Boraginaceae. Its taxonomic position is somewhat uncertain. Traditionally, and under the Cronquist system, the taxon was given family rank under the name Hydrophyllaceae, and treated as part of the order Solanales. More recent systems have recognised a close relationship to the borage family, Boraginaceae, initially by placing Hydrophyllaceae and Boraginaceae together in an order Boraginales,[1] and in the 2016 APG IV system by including Hydrophyllaceae in Boraginaceae.[2] However, the placement and circumscription of Boraginaceae is still uncertain. Some sources now split off Hydrophyllaceae again (together with Namaceae).[3][4]
Plants in this subfamily may be annual or perennial herbs or shrubs, with either a prostrate or an erect stem. Most have a taproot. The flowers are bisexual, and normally radial, with 5 petals and 5 stamens. About 20 genera, containing around 300 species, are recognised; many of them are native to the western United States.[citation needed]
The subfamily takes its name from the genus Hydrophyllum (waterleaf). Members include Emmenanthe (whispering bells), Nemophila (baby blue eyes) and Phacelia (scorpionweed).[5]
Genera
As of November 2024[update], the Angiosperm Phylogeny Website accepted the family Hydrophyllaceae rather than the subfamily Hydrophylloideae, and included 12 genera:[5]
The division into two families rather than one subfamily follows the recommendations of the Boraginales Working Group.[7]
References
^e.g. Gottschling, M., Hilger, H.H., Wolf, M. & Diane, N. (2001). Secondary structure of the ITS1 transcript and its application in a reconstruction of the phylogeny of Boraginales. Pl. Biol. 3: 629โ636.
^Vasile, Maria-Anna; Jeiter, Julius; Weigend, Maximilian & Luebert, Federico (2020). "Phylogeny and historical biogeography of Hydrophyllaceae and Namaceae, with a special reference to Phacelia and Wigandia". Systematics and Biodiversity. 18 (8): 757โ770. Bibcode:2020SyBio..18..757V. doi:10.1080/14772000.2020.1771471. hdl:20.500.11811/11843.
^Stevens, P.F. (2001 onwards). "Boraginaceae". Angiosperm Phylogeny Website. Retrieved 2024-11-11.