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Isocoma humilis

(Zion Goldenbush)

Overview

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Extirpated

Threat status

Interesting Facts

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Common Names

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Common Names in English:

Zion Goldenbush, Zion Jimmyweed

Description

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Family Compositae

The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.

Genus Isocoma

Perennials or subshrubs , (4-) 20-120(-150) cm (bases often woody). Stems usually strictly erect , few-branched, glabrous or hispidulous , villous , or tomentose , usually gland-dotted (sessile or slightly sunken in pits), sometimes stipitate-glandular , rarely eglandular , often resinous . Leaves mostly cauline; alternate; sessile; blades 1-nerved, linear to oblanceolate or obovate , margins entire or toothed to pinnatifid (teeth or lobes often spinulose-tipped), faces glabrous or hispidulous, villous, or tomentose, usually gland-dotted (in pits). Heads discoid , (sessile or subsessile ) in compact clusters borne in terminal corymbiform arrays, rarely borne singly. Involucres obconic to turbinate or campanulate , (3-9.5 ×) 2-8 mm. Phyllaries 15-30 in (3-) 4-6 series, 1-nerved (midnerves usually barely evident; flat to convex ), oblong- to elliptic-lanceolate, unequal, margins narrowly scarious , apices sometimes green, faces glabrous or tomentose, sometimes gland-dotted, sometimes with resin pockets . Receptacles flat, pitted , epaleate. Disc florets 8-34, bisexual , fertile ; corollas yellow with dark orange-resinous veins, tubes (with at least a few glandular hairs ) longer than abruptly ampliate , goblet-shaped throats (tube elevating corollas above involucres at flowering), lobes 5, erect, deltate (elongating at maturity, unequal, outer prominently bent or leaning outward, abruptly enlarged) ; style-branch appendages narrowly triangular. Cypselae (brownish) obpyramidal , terete or subterete, 5-11-ribbed (sometimes thick and resinous), faces sericeous ; pappi persistent , of 40-50 unevenly thick, unequal, barbellate , apically attenuate bristles in 2(-3) series. x = 6.

Species 16: sw United States, Mexico.

Isocoma is recognized by its subshrubby habit, gland-dotted (sometimes stipitate-glandular), often resinous leaves, compactly clustered discoid heads in terminal, corymbiform arrays, goblet-shaped disc corollas, and base chromosome number of x = 6. H. M. Hall (1928) regarded the group as a section of Haplopappus, as did A. Cronquist (1994). Naturally occurring hybrids in south-central Mexico have been observed between Isocoma veneta (Kunth) Greene and Xanthocephalum humile (Kunth) Bentham (R. L. Hartman and M. A. Lane 1991).[1]

Physical Description

Species Isocoma humilis

Herbage villosulous or tomentose to sparsely hispidulous (hairs short, crisped , white), not resinous . Leaf blades narrowly oblanceolate , 5-10(-18) mm, margins usually toothed or lobed (teeth or shallow lobes in 1-2(-3), pinnately arranged pairs), sometimes entire. Involucres 5-6 × 6-7 mm. Phyllary apices greenish, not aristate , gland-dotted, without resin pockets . Florets 19-28; corollas 4-5 mm. Cypsela ribs not forming apical horns. [source]

It is recognized by its low stature (mostly 4-8 cm) and rounded habit, villosulous vestiture, small, toothed leaves, relatively large, many-flowered heads borne singly or in pairs, and small corollas and cypselae. [source]

Habit: Subshrub , Shrub

Flowers: Bloom Period: September, October.

Habitat

Sandy soils from red sandstone, pinyon-juniper-shrub; of conservation concern; 1000-1200 m [2].

Biology

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Reproduction

Duration: Perennial

Taxonomy

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Synonyms

Haplopappus integrifolius Porter Ex Gray • Haplopappus integrifolius typicus Hall • Haplopappus leverichii Cronquist

Notes

Name Status: Accepted Name .

Comment: Data Providers: IPNI, Tropicos. GCC LSID: urn :lsid:compositae.org:names:FF4DF658-5C6D-4036-9874-F02108CE7789

Last scrutiny: 14-Aug-09

Similar Species

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Members of the genus Isocoma

ZipcodeZoo has pages for 28 species, subspecies, varieties, forms, and cultivars in this genus:

I. acradenia (Alkali Goldenbush) · I. acradenia (Greene) Greene var. bracteosa (Greene) Nesom (Alkali Goldenbush) · I. acradenia (Greene) Greene var. eremophila (Greene) Nesom (Alkali Goldenbush) · I. acradenia acradenia (Alkali Goldenbush) · I. acradenia var. bracteosa (Alkali Goldenbush) · I. acradenia var. eremophila (Alkali Goldenbush) · I. arguta (Carquinez Goldenbush) · I. azteca (Aztec Goldenbush) · I. coronopifolia (Common Goldenbush) · I. coronopifolia var. coronopifolia (Common Jimmyweed) · I. drummondii (Drummond Goldenweed) · I. humilis (Zion Goldenbush) · I. menziesii (Menzies Goldenbush) · I. menziesii var. decumbens (Menzies' Goldenbush) · I. menziesii var. decumbens (Greene) Nesom (Menzies' Goldenbush) · I. menziesii var. diabolica (Menzies' Goldenbush) · I. menziesii var. diabolica Nesom (Menzies' Goldenbush) · I. menziesii var. menziesii (Menzies' Goldenbush) · I. menziesii var. sedoides (Menzies' Goldenbush) · I. menziesii var. sedoides (Greene) Nesom (Menzies' Goldenbush) · I. menziesii var. vernonioides (Menzies' Goldenbush) · I. menziesii var. vernonioides (Nutt.) Nesom (Menzies' Goldenbush) · I. pluriflora (Rayless Goldenrod) · I. rusbyi (Rusby's Goldenbush) · I. scopulorum (Grand Canyon Glowweed) · I. tenuisecta (Burrow Goldenweed) · I. veneta (Jimmyweed) · I. veneta var. veneta (Jimmyweed)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 28, 2008:

Identifiers

Footnotes

  1. Guy L. Nesom "Isocoma". in Flora of North America Vol. 20 Page 7,13, 89, 438, 439, 445. Oxford University Press. Online at EFloras.org. [back]
  2. "Isocoma humilis". in Flora of North America Vol. 20 Page 440,444. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/15/2012