Perideridia howellii
Perideridia howellii is a species of flowering plant in the family Apiaceae known by the common name Howell's yampah.[1] It is native to the mountains of Oregon and northern California, where it grows in moist soils, often near streams and rivers.[2] It is a perennial herb which may exceed 1.5 metres in maximum height, its slender, erect stem growing from a cluster of many narrow fibrous roots measuring up to 15 centimetres long.[2] Leaves near the base of the plant have lance-shaped blades up to half a metre long which are divided into many leaflets made up of toothed, oval segments.[2] Leaves higher on the plant are similar, but generally smaller. The inflorescence is a compound umbel of many spherical clusters of small white flowers.[2] These yield ribbed, oblong-shaped fruits each about half a centimetre long.[2]
| Perideridia howellii | |
|---|---|
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Apiales |
| Family: | Apiaceae |
| Genus: | Perideridia |
| Species: | P. howellii |
| Binomial name | |
| Perideridia howellii (J.M.Coult. & Rose) Mathias | |