Key to Isocoma

View taxon page for Isocoma

(For a list of species in Isocoma, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Phyllary tip swollen, with a prominent 

linear 

Elongate, with nearly parallel sides; narrower than elliptic or oblong.

to widely 

elliptic 

In the shape of a flattened circle or ellipse; wider than linear

resin gland (resin glands rarely >= 2), often with additional minute dot-like resin glands

2. Leaves all 

entire 

Having margins that are continuous and smooth (i.e., without teeth, lobes, etc.).

or proximal leaves toothed or lobed ..... I. acradenia (2)

3. Phyllary tips rounded and not or occasionally weakly soft-pointed; flowers 18–24 ..... var. acradenia

3' Phyllary tips blunt to 

acute 

Having a short-tapered, sharp tip, the sides convex or straight and converging at less than a right angle.

(inner ones), abruptly soft-pointed; flowers 20–27 ..... var. bracteosa (2)

2' Leaves all toothed or pinnately lobed

4. Flowers 10–13; phyllaries minutely awn-tipped ..... I. arguta (2)

4' Flowers 12–27; phyllaries rounded and not or minutely awn-tipped ..... I. acradenia (2)

5. Flowers 20–27; phyllaries abruptly soft-pointed ..... var. bracteosa (2)

5' Flowers 12–20; phyllaries rounded and not awn-tipped or very weakly awn-tipped ..... var. eremophila

1' Phyllary tip dotted with minute resin glands (rarely with >= 1 weakly developed larger resin glands)

6. Flowers 10–13; phyllaries minutely awn-tipped ..... I. arguta (2)

6' Flowers 15–28; phyllaries acute, not at all awn-tipped, or with weakly developed projection at tip ..... I. menziesii

7. Leaf oblong-oblanceolate to widely obovate, coarsely 

serrate 

Having margins with sharp, fine to coarse teeth generally pointing tipward, not outward; margins with such teeth on such primary teeth are doubly serrate.

, ± thick, fleshy; stem and leaves glabrous, glandless – plants 

decumbent 

lying mostly flat on the ground but with tips curving up.

or 

prostrate 

Lying flat on the ground.

..... var. sedoides

7' Leaf linear, narrowly 

oblong 

Longer than wide, with nearly parallel sides; wider than linear.

, or oblanceolate to obovate, entire, toothed, or shallowly lobed, not fleshy (or if fleshy, at least stem long-soft hairy); stem and leaves glabrous to long-soft hairy, 

tomentose 

Covered with densely interwoven, generally matted hairs.

, or glandular

8. Herbage stalked-glandular, without nonglandular hairs or finely and closely ± gray cobwebby-tomentose

9. Plant prostrate or decumbent to ± 

erect 

Upright; vertically oriented.

; leaves 2–4 mm wide; heads in ± flat-topped or panicle-like cluster; fruit generally 2.3–3.6 mm; s SCo, s ChI, s PR ..... var. decumbens (2)

9' Plant strictly erect; leaves 4–10 mm wide; heads in ± flat-topped cluster; fruit generally 4–5 mm; s SnFrB, n SCoRI ..... var. diabolica (2)

8' Herbage not prominently glandular, otherwise glabrous to long-soft-hairy or tomentose

10. Plant prominently long-soft-hairy or tomentose

11. Herbage finely and closely gray tomentose; leaves narrowly oblanceolate, entire or few-toothed; stems decumbent to erect ..... var. decumbens (2)

11' Herbage with long, 

spreading 

Oriented more or less perpendicularly to the axis of attachment; often, more or less horizontal.

± thick-based hairs; leaves oblanceolate or oblong-oblanceolate, at least proximal leaves toothed along most of margin; stems generally erect ..... var. vernonioides (2)

10' Plant glabrous or slightly hairy, sometimes resinous

12. Leaves entire or few-toothed at tip ..... var. menziesii

12' At least proximal leaves serrate

13. Corolla 6–7 mm; fruit (3.8)4.5–5 mm ..... var. diabolica (2)

13' Corolla 5–7 mm; fruit 2.3–3.6 mm ..... var. vernonioides (2)

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