Genus Allagopappus in Tribe Inuleae

Genus Description

Allagopappus is a small genus of evergreen shrubs in the Asteraceae tribe Anthemideae (subtribe Chrysantheminae sensu Oberprieler et al., 2009), comprising two accepted species distributed across the Canary Islands. The name Allagopappus canariensis (Willd.) Cass. ex Ball is commonly treated as the type element for the genus, although precise lectotypification is not uniformly cited across contemporary sources (WFO, 2024). The genus is diagnosed by much-branched, compact habits; alternate leaves that are linear to narrowly ovate with revolute margins and punctate glands; and inflorescences of solitary, heterogamous, discoid capitula. Flowers are unisexual: outer florets are female (pistillate) with reduced corollas, while central florets are bisexual but functionally staminate; the achenes are strongly compressed with lateral ribs and a well-developed pappus of many unequal bristles. Allagopappus stands out among Canary Anthemideae in combining discoid heads, lateral ribbed achenes, and a conspicuous pappus—a character assemblage that figures in tribal keys and separates it from nearby shrubby genera (Hansen, 2000; Francisco-Ortega et al., 2007; Oberprieler et al., 2009).

Diversity is tightly clustered: Allagopappus canariensis is widespread on Tenerife, La Palma, Gran Canaria, and La Gomera, while Allagopappus dichotomus (Webb) Christ is more narrowly distributed on Tenerife and La Gomera (Bramwell & Bramwell, 2001; WFO, 2024). Both are most frequent in laurisilva margins, scrub, and coastal cliffs at low to mid elevations, often on acidic soils. The Canary Islands hotspot and associated edaphic mosaics underpin endemism, and the genus contributes to the archipelago’s distinctive leñoso (woody) scrub flora (Francisco-Ortega et al., 2007; Bramwell & Bramwell, 2001).

Intrinsic biology remains incompletely documented; achenes with and without pappus suggest mixed dispersal strategies including local wind-assisted dissemination and short-distance gravity movement.Chromosome counts are occasionally reported at 2n=18, consistent with the base number x=9 prevalent across Anthemideae, but counts vary in perennials and require confirmation in modern karyosystematic surveys (POWO, 2024).

Taxonomically, Allagopappus is currently accepted as distinct from Pterygostemon and other Canary Anthemideae in standard checklists (WFO, 2024; POWO, 2024). Subgeneric divisions are not widely applied. Historically, the two species have been placed under Chrysanthemum and related segregate genera (Hansen, 2000), but recent molecular and morphological syntheses support a separate genus with clear Apollo–Chrysanthemum–Leucanthemopsis allies within Chrysantheminae (Francisco-Ortega et al., 2007; Oberprieler et al., 2009). Alternative treatments sensu Llorens & Roquet (1985) anticipate broader concept boundaries within Canary Anthemideae; current consensus favors narrow circumscription with moderate confidence (WFO, 2024).

Human relevance is modest: Allagopappus is locally collected for ornamental horticulture in the Canaries and increasingly used in xeriscapes for its drought tolerance and neat habit, with no known timber or crop value (Bramwell & Bramwell, 2001; WFO, 2024).

Conservation and outlook: Both species are assessed as secure, though habitat pressure from urbanization and invasive species warrants ongoing monitoring; refined phylogeography and chromosome surveys would clarify diversification pathways (Francisco-Ortega et al., 2007; WFO, 2024).

• Allagopappus canariensis ((Willd.) Greuter)
• Allagopappus viscosissimus (Bolle)