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five-needle pricklyleaf

Photo is of parent taxon

Hartweg's pricklyleaf

Habit Perennials or subshrubs, ± grayish to green, to 15(–25) cm, usually puberulent to canescent, sometimes glabrescent or glabrous.
Stems

erect or spreading.

Leaves

mostly opposite;

blades mostly pinnately lobed, 6–28+ mm overall, lobes 3–11 linear to filiform (usually stiff, setiform).

12–34 mm overall, lobes 3–7, unequal (terminal lobes usually notably longer than laterals).

Peduncles

20–100 mm, puberulent or glabrous.

2–5 cm.

Involucres

obconic to campanulate or hemispheric, 4–6 mm.

cylindric, 3–5 × 2–3.5 mm.

Ray florets

(8–)12–21;

corollas yellow to orange-yellow, laminae 2–6(–8) × 1–3 mm.

Disc florets

16–40 or 50–80;

corollas yellow, 2–4 mm (tending to zygomorphy in peripheral florets in some plants).

16–40.

Phyllaries

12–21, margins of outer distinct 1/5 to nearly all their lengths, abaxial faces puberulent or glabrous.

ca. 13, margins of outer distinct 1/3 or less their lengths, abaxial faces sparsely puberulous, often glabrescent.

Calyculi

0, or of 1–5 deltate bractlets, lengths less than 1/2 phyllaries.

of 3–5 bractlets.

Cypselae

2–3 mm;

pappi of 10 erose and/or aristate scales mostly 1–3 mm.

Pappi

of 5 erose scales alternating with 5, 1–3-aristate scales.

Thymophylla pentachaeta

Thymophylla pentachaeta var. hartwegii

Phenology Flowering early spring and late summer, following rains.
Habitat Calcareous outcrops and bluffs, deserts
Elevation 1500–2500 m (4900–8200 ft)
Distribution
from FNA
AZ; CA; NM; NV; TX; UT; Mexico [Introduced(?) in South America (Argentina)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; NM; TX; Mexico
Discussion

Varieties 4 (4 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Involucres cylindric, 2–3.5 mm diam.; disc florets 16–40
var. hartwegii
1. Involucres obconic, campanulate, or hemispheric, mostly 4–5 mm diam.; disc florets 50–80
→ 2
2. Peduncles 20–50 mm; margins of outer phyllaries distinct almost to bases
var. belenidium
2. Peduncles (40–)50–100 mm; margins of outer phyllaries distinct less ca. 1/2 or ca. 1/3 their lengths
→ 3
3. Leaf lobes mostly 9–11; phyllaries usually glabrous or glabrescent, rarely hairy
var. pentachaeta
3. Leaf lobes mostly 5–7(–10); phyllaries densely puberulent
var. puberula
Source FNA vol. 21, p. 241. FNA vol. 21, p. 242.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Pectidinae > Thymophylla Asteraceae > tribe Heliantheae > subtribe Pectidinae > Thymophylla > Thymophylla pentachaeta
Sibling taxa
T. acerosa, T. aurea, T. concinna, T. micropoides, T. setifolia, T. tenuiloba, T. tephroleuca
T. pentachaeta var. belenidium, T. pentachaeta var. pentachaeta, T. pentachaeta var. puberula
Subordinate taxa
T. pentachaeta var. belenidium, T. pentachaeta var. hartwegii, T. pentachaeta var. pentachaeta, T. pentachaeta var. puberula
Synonyms Hymenatherum pentachaetum, Dyssodia pentachaeta Hymenatherum hartwegii, Dyssodia hartwegii, Dyssodia pentachaeta var. hartwegii
Name authority (de Candolle) Small: Fl. S.E. U.S., 1295, 1341. (1903) (A. Gray) Strother: Sida 11: 377. (1986)
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