Flora of Dominica, Part 2 - Smithsonian Institution Libraries

30 ASTERACEAE SMITHSOMAN CONTRIBUTIONS TO BOTANY
I am grateful to Dr. H.E. Robinson who helped with the key
and in other ways.
Cultivated Genera of Asteraceae
Artemisia absinthium Linnaeus and Artemisia vulgaris
Linnaeus were cited as cultivated in the Antilles by Adjanohoun
et al. (1985:71, pl. 37-38), suggesting both are on
Dominica (new records, if true).
Ayapana triplinervis (Vahl) King & Robinson was attributed
to Dominica as Eupatorium triplinerve Vahl by Vdez
(1957:8 l), extrapolated from Britton and Wilson’s citation
(1925, 6:289), “Martinique; Guadeloupe.” It has been cultivated
on the French Islands and escaped but no material from
Dominica has been seen. It has opposite, entire, lanceolate
leaves tapering to a subsessile base. However, Adjanohoun et
al. (198581, pl. 48) reported it as widely cultivated for its
medicinal usages, another new record for Dominica if there.
Cosmos caudatus Kunth, with pink ligules, was reported by
Domin (1930d79) as collected by Imray.
Cosmos sulphureus Cavanilles, with yellow or orange
ligules, was reported by Adjanohoun et al. (198575, pl. 42).
These have opposite, pinnatisect leaves and beaked achenes
with barbed awns.
Helianthus annuus Linnaeus, the sunflower, may be cultivated
on Dominica but no specimens have been seen. It has
alternate, dentate and rough leaves and a large head 30 or more
cm across.
Launaea intybacea (Jacquin) Beauverd is reported as
“occasionally met in the Lesser Antilles” by Adjanohoun et al.
(198585, pl. 51). This, if true for Dominica, would be a new
record for the island.
Tugeres erecta Linnaeus (African marigold) was reported as
collected by Domin (193N79). Tagetes patula Linnaeus
(French marigold) was illustrated by Adjanohoun et al.
(198591, pl. 58). These species have opposite or alternate,
pinnatisect leaves and connate involucral bracts. Howard
(1989,6601) treated these as synonyms.
Zinnia elegans Jacquin was collected in cultivation by
Domin (193N73). This and other cultivated zinnias have
opposite, sessile, and entire leaves.
Excluded Genera of Asteraceae
Borrichia arborescens (Linnaeus) A.P. Candolle was ataibuted
to Dominica by Velez (1957:80). No collections have been
seen and it is unlikely that this shrubby coastal calciphile (with
opposite, entire, oblanceolate leaves) survives on Dominica.
Helenium quadridentatum Labillardiere was credited to
Dominica by Adjanohoun et al. (1985:83, pl. 49) but no
material has been seen.
Lagascea mollis Cavanilles was attributed to Dominica as
Nocca mollis (Cavanilles) Jacquin by Velez (1957:80),
extrapolated from Britton and Wilson’s citation (1925,6:300),
“Anguilla to Barbados.” Although it is weedy, the few
collections made on the French islands indicate that it is
introduced and rare there. No collections from Dominica have
been seen. Its leaves are generally opposite. Like Rolandra it
has 1-flowered heads gathered in head-like glomerules but,
unlike Rolandra, with a pseudo-involucre. The true involucral
bracts are partly united.
1. Leaves opposite.
2. Pappus bristles with prominent retrorse barbs .............. Bidens
2. Pappus without retrorse barbs.
3. Leaves compound or deeply pinnatifid ............... Ambrosia
3. Leaves simple.
4. Fruits spiny, at least one large terminal spine hooked ............
.............................. Acanthospermum
4. Fruits not spiny.
5. Leaf margins, near base, pectinate (with elongate bristles); lower leaf
surface with large, dark glandular “dots” ............. Pectis
5. Leaf margins not pectinate; lower surface without glandular “dots” or, if
any, then inconspicuous.
6. Heads with receptacular bracts (pales, sometimes bristles); heads
heterogamous (outer florets female or neuter), corollas often yellow.
7. Heads conspicuously radiate (ray-florets longer than involucre).
8. Pappus of many plumose, capillary bristles ........ Tridux
8. Pappus lacking or a cup of united scales.
9. Involucral bracts erect, longer than achenes and receptacular
pales.. ....................... Wedelia
9. Involucral bracts deflexing, shorter than achenes and receptacular
pales. ....................... Wulffia
7. Heads inconspicuously radiate (ray-florets shorter than involucre).