Contains 9 accepted taxa overall.
Characteristics
Conyza is embedded within the genus Erigeron, and indeed two common species in Florida were originally described under Erigeron by Linnaeus. The inclusion of Aphanostephus, Conyza, and Darwiniothamnus would likely render Erigeron monophyletic (Andrus et al. 2009; Jafari et al. 2015).
Classification
Citation
ERIGERON Linnaeus, Sp. Pl. 863. 1753, nom. cons. propos.
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TYPE: Erigeron uniflorus Linnaeus, typ. cons. propos.
Species
| Scientific Name | Common Name | Herbarium Specimens | Status | Photos |
|---|---|---|---|---|
| Erigeron annuus | Annual Fleabane | |||
| Erigeron bonariensis | South American Horseweed | |||
| Erigeron canadensis | Common Horseweed | |||
| Erigeron philadelphicus var. philadelphicus | Philadelphia-daisy | |||
| Erigeron pulchellus var. pulchellus | Robin's-plantain | |||
| Erigeron pusillus | Southern Horseweed | |||
| Erigeron quercifolius | Oak-leaved Fleabane | |||
| Erigeron strigosus var. strigosus | Common Rough Fleabane | |||
| Erigeron vernus | Whitetop Fleabane |
Identification Key
1. Plant 4-15(20) cm long; heads 1-2 per stem
1. Plant (10)15-150+ cm long; heads 1-200+ per stem
2
2. Stem usually densely leafy; leaves generally linear to narrowly lanceolate or narrowly oblanceolate, 7-30 times longer than wide; ray corolla laminae 0-2 mm long; annuals
3
2. Stem sparsely to moderately leafy; leaves generally oblanceolate, spatulate, ovate, lanceolate, to oblong, 2-15 times longer than wide; ray corolla laminae 0.5-8 mm long; annuals or perennials
5
3. Leaf surfaces mostly densely strigose to hispidulous; phyllaries usually hispidulous to strigose; receptacles 3-5 mm wide in fruit; pistillate florets 60-150+; pappi 3-4+ mm long
3. Leaf surface mostly glabrate to sparsely strigose or hispidulous; phyllaries glabrous to sparsely strigose; receptacles 1-3 mm wide in fruit; pistillate florets 20-45+; pappi 2-3 mm long
4
4. Phyllaries usually glabrous, sometimes sparsely strigose; corollas of pistillate florets with laminae 0.3–1+ mm; cypselae uniformly pale tan to light gray-brown
4. Phyllaries usually sparsely strigose; corollas of pistillate florets with laminae 0 or to 0.3 mm; cypselae pale tan (usually some in each head with reddish nerves)
5. Ray laminae to 2 mm long, shorter than the phyllaries; basal leaves mostly not persistent and not rosette-forming
5. Ray laminae 3-8 mm long, subequal to longer than the phyllaries; larger leaves sometimes basal, persistent, and rosette-forming
6
6. Pappi of rays and discs often dissimilar, the ray without bristles, the disc with 0 or 8-15 bristles
7
6. Pappi of rays and discs similar, the ray and disc with 10-30 bristles
8
7. Stems hairs spreading, sometimes strigose distally; basal leaves usually withering by flowering, cauline little reduced proximal to midstem, blades lanceolate to oblong or ovate, margins coarsely serrate to nearly entire
7. Stems hairs usually ascending, rarely spreading; leaves: basal usually persistent to flowering, blades spatulate to broadly or narrowly oblanceolate to linear, cauline usually gradually reduced distally, margins entire or obscurely serrate or crenate
8. Plant mostly glabrate; leaf margins entire to faintly toothed; cauline leaves extremely reduced, usually <3 cm long and <0.7 mm wide; cypselae 4-nerved, 1.2-1.6 mm long
8. Plant usually strigose, hirsute, to villous; at least some leaves with distinct teeth; cauline leaves gradually to strongly reduced, usually some >3 cm long or >0.6 mm wide; cypselae 2-nerved, 0.6-1.5 mm long
9
9. Plants with sparsely scaly rhizomes
9. Plants without rhizomes
10
10. Basal leaves petiolate, the blade base abruptly contracted to a distinct petiole; cauline leaves not clasping; ray corollas 3-5 mm long
10. Basal leaves sessile, the blade base cuneate or attenuate; cauline leaves clasping to subclasping; ray corollas 4-10 mm long
11
11. Stem internodes usually shorter than the subtending leaves, the leaves gradually reduced upwards; involucres 4-6 mm long, 6-15 mm wide; ray florets 150-250(400), corollas usually white or pinkish, 5-10 mm; pappus bristles 15-20(30)
11. Stem internodes longer than the subtending leaves, the leaves strongly reduced upwards; involucres 2.5-4 mm long, 4.5-10 mm wide; ray florets 100-150, corollas usually blue, sometimes white to pink, 4-6 mm; pappus bristles 10-15
Genus Synonyms
| Synonym | Full Citation | Basionym | Type |
|---|---|---|---|
| No synonyms found. | |||