Date: September 23, 2011. Herbert Hoover NHS: (map)
| Classification Hierarchy | |
| Kingdom | Plantae |
| Subkingdom | Tracheophyta |
| Superdivision | Spermatophyta |
| Division | Magnoliophyta |
| Class | Magnoliopsida |
| Subclass | Asteridae |
| Order | Asterales |
| Family | Asteraceae |
| Genus | Eupatorium |
| Species | Eupatorium altissimum |
Date: September 23, 2011. Herbert Hoover NHS: (map)
Scientific Name: Eupatorium altissimum (Dedicated to Mithridates Eupator, 132-63 B.C., who is said to have used the plant medicinally; altissimum - tallest)
Common Name: Tall Boneset, Tall Thoroughwort
Origin: Native
Notes: Tall boneset is easy to confuse with false boneset (Brickellia eupatorioides, syn. Kuhnia eupatorioides). The leaves are a clue. Tall boneset has opposite leaves, each with three prominent veins underneath and five florets per head, False boneset has opposite and alternate leaves with one or three vein(s) from the leaf base and more than five (6-15) florets per head.
Additional references: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11.
Flowers: August; corolla-white, tubular, 5 lobed; capitulum (flower head) typically with 5 florets; phyllaries downy, tubular, the larger (inner ones) with rounded summits; fruit cypselae (achenes).
Leaves: lancelate, tapering to sessile base, blade with tiny resinous dots, margins entire or serrate above the middle, typically 3 (sometimes 5) parallel veins prominent beneath.
Glossaries of botanical terms: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
