Brickellia

Schilling, Edward E., Scott, Randall W. & Panero, Jose L., 2015, A revised infrageneric classification for Brickellia (Asteraceae, Eupatorieae), Phytotaxa 234 (2), pp. 151-158 : 152

Key to the Sections of Brickellia

1 Cypselae with 4–6 ribs, sometimes obcompressed; plants annual or perennial ............................................................................... 2

- Cypselae with 8–10 ribs, prismatic; plants perennial ....................................................................................................................... 3

2 Leaves setose, with prickles at tips of lobes; corollas tubular .......................................................................... 1. B. sect. Barroetea

- Leaves not setose, lacking prickles at tips of lobes; corollas funnelform .................................................. 8. B. sect. Phanerostylis

3 Inflorescence axis with few to numerous small, undeveloped heads (the crowded short phyllaries giving the appearance of gemmae) interspersed with fully developed flowering heads .................................................................................. 4. B. sect. Gemmipedium

- Inflorescence with all heads developing fully .................................................................................................................................. 4

4 Pappus bristles usually plumose; plants herbaceous perennials, with usually alternate leaves and few-flowered (8–10) heads ....... ............................................................................................................................................................................... 5. B. sect. Kuhnia

- Pappus not plumose, usually barbellate; plants herbaceous or shrubby, leaves alternate or opposite, heads with few to many flowers .............................................................................................................................................................................................. 5

5 Larger leaves with naked basal veins, the lateral veins marginal at the point of divergence from the midrib ( Fig. 1 ) ....................... ........................................................................................................................................................................... 2. B. sect. Brickellia

- Larger leaves with the first pair of lateral veins diverging from the midrib above the leaf margin ................................................. 6

6 Plants annuals or weak perennials; heads 11–14 flowered; if perennial, leaves hastately toothed or lobed, petioles 2–3.5 cm long .................................................................................................................................................................. 6. B. sect. Leptanthodium

- Plants perennials, herbaceous or shrubby; heads (3–)11–100-flowered; if leaves hastately toothed or lobed, heads usually more than 15-flowered or petioles less than 2 cm long ............................................................................................................................. 7

7 Leaves sessile or short-petiolate; plants usually shrubs; heads erect; corollas funnelform ........................ 7. B. sect. Microphyllae

- Leaves usually petiolate; plants shrubs or perennial herbs; heads erect or nodding; corollas funnelform or tubular ...................... 8

8 Leaves usually cuneate at base; heads usually with 13–25 flowers; involucral bracts usually weakly imbricate; pappus length usually 6 mm or less; pappus bristles usually fewer than 40 .................................................................... 8. B. sect. Xerobrickellia

- Leaves usually truncate or cordate at base; heads with (15)25–100 flowers; involucral bracts strongly imbricate; pappus length usually 6 mm or more; pappus bristles usually more than 40 .................................................................... 3. B. sect. Coleosanthus

Figures

FIGURE 1. Leaf of Brickellia cordifolia showing the character trait of naked basal veins (arrows; key couplet 5) that characterizes B. sect. Brickellia.