Dahlia excelsa Benth.
tree dahlia
Erect perennial herb, 2-6 m tall, with tuberous roots. Stems sparsely hairy, especially about nodes, branched above at flowering, dying back to woody bases in winter. Lower cauline lvs shortly petiolate, sparsely clothed in short hairs, ovate-triangular, 2-pinnate with 6-9 primary pairs and each of lowest pair with 7-9 leaflets; petiole with 2 lateral angles on upper surface; leaflets mostly not lobed, sometimes 2-3-lobed, subsessile, ovate to elliptic, acuminate, serrate, 5-15 cm long. Upper cauline lvs 1-pinnate or simple. Capitula 9-18 cm diam., usually slightly nodding. Outer involucral bracts 5, sparsely hairy, ovate to spathulate or pandurate, 10-15 mm long, recurved at anthesis; inner bracts 8, ovate-triangular to elliptic, with broad membranous margin, 20-25 mm long. Receptacular scales ovate-triangular, acute. Ray florets c. 8; ligules pink, lavender to pinkish purple. Disc florets numerous, golden. Achenes linear, 7-17 mm long.
N.: Auckland City, Wellington City, Hamilton; S.: Nelson City.
Mexico, C. America, Colombia 1984
Waste places and coastal cliffs.
FL Apr-Jun.
Tree dahlia is cultivated, especially in areas free from heavy frosts. It seeds freely and has established locally in the wild as an escape from cultivation.
D. excelsa and D. imperialis Ortgies are treated as separate spp. by some authors. However, as noted by Sorensen (op. cit.) they are probably variants of the same sp.; D. imperialis, being the later name, is treated here as a synonym.
