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   het-hairs.jpg (17509 bytes)

 Heterotheca Cass. 

PRAIRIE AND MONTANE GOLDENASTERS

Heterotheca includes all the goldenasters that have leaf hairs consisting of bone-shaped (osteolate) cells with knobbed surfaces;.  The genus is divided into three sections based on fruit characteristics, presence or absence of ray florets and growth form. Species of Heterotheca are native to southwestern Canada, much of the U.S. and most of México (map).

Heterotheca sect. Heterotheca includes seven species with heterocarpic heads (two kinds of fruit; e.g., H. subaxillaris). Three central Mexican species are perennials. The four species native to the U.S. are weedy annuals sometimes reaching 2 m in height: H. grandiflora native to CA; H. psammophila native to AZ, NM and TX and adjacent Mexico; H. latifolia native to the southern Great Plains and Ozark outer Piedmont areas; H. subaxillaris native to the outer coastal plain from Long Is., NY to TX and into Mexico.

Heterotheca sect. Ammodia includes one species H. oregona with four varieties native gravel bars and arroyos from WA to central CA. It has rayless heads (var. rudis and var. scaberrima) on erect branching stems (var. scaberrima).

Heterotheca sect. Phyllotheca (Nutt.) Harms (Semple 1996) includes 20 species of mostly herbaceous perennials ranging in height from a few cm (H. jonesii) to more than 1.2 m (H. shevockii). Most species are usually 10-50 cm tall (e.g., H. pumila). Many species are restricted to particular soil types or habitats (e.g., H. brandegei, Baha CA Norte; H. monarchensis, CA; a few species are widely distributed (e.g., H. villosa; nine varieties). Species are defined by different combinations of leaf traits (size, shape, numbers of hairs and glands), head features (size, numbers of florets) and habit (growth form) features.

Heterotheca sect. Phyllotheca (all illustrations by J.C. Semple © unless indicated):

  • H. barbata
  • H. brandegii
  • H. camporum var. camporum
  • H. camporum var. glandulissimum, habit (cult Waterloo, orig: TN.); heads
  • H. canescens, habit (TX. Hays Co.), flowering shoot (KS. Barber Co.)
  • H. fulcrata var. amplifolia
  • H. fulcrata var. arizonica, habit (AZ. Gila Co., type locale)
  • H. fulcrata var. fulcrata, flowering shoot (CO. Boulder Co.)
  • H. fulcrata var. senilis, habit, leaves (TX. Culberson Co.)
  • H. gypsophila
  • H. monarchensis, habit, flowering shoot (CA. Fresno Co., Monarch Wilderness; photo's by D. York)
  • H. marginata, habit by roadside margin, flowering shoot (AZ. Maricopa Co.)
  • H. mexicana
  • H. mucronata var. harmsiana
  • H. mucronata var. mucronata
  • H. pumila, habit (CO. Gunnison Co.)
  • H. rutteri; flowering shoot; (AZ. Santa Cruz Co.)
  • H. sessiliflora subsp. bolanderi, habit, flowering shoot (CA. Medecino Co.)
  • H. sessiliflora var. bolanderioides, habit (robust, CA. Santa Cruz Co.; small, CA. Contra Costa Co.), flowering head
  • H. sessiliflora var. camphorata, flowering shoot (CA. Santa Cruz Co.)
  • H. sessiliflora var. echioides, habit, flowering shoot (CA. Ventura Co.)
  • H. sessiliflora var. fastigiata, flowering shoot, leaves (CA. Los Angeles Co.)
  • H. sessiliflora var. sanjacintensis, habit, leaves, flowering shoot (CA. San Bernardino Co., type locale)
  • H. sessiliflora subsp. sessiliflora, flowering shoot (CA. San Diego Co.; type species of the section)
  • H. shevockii, habit, stem leaves (CA. Kern Co.)
  • H. stenophylla var. angustifolia, flowering shoots (OK. Beckham)
  • H. stenophylla var. stenophylla, habit (KS), heads (OK)
  • H. thiniicola
  • H. villosa var. ballardii
  • H. villosa var. depressa, habitat, flowering shoot (WY. Yellowstone N.P.; by Old Faithful Geyser.)
  • H. villosa var. foliosa and var. nana (including var. horrida), shoots (CO. Larimer Co.)
  • H. villosa var. minor (including var. hispida), habit (CA. Shasta Co.), flowering shoots (CA. Plumas Co. and WY. Fremont Co.),
  • H. villosa var. pedunculata, flowering shoot (CO. Archuleta Co.), stem and leaves (AZ)
  • H. villosa var. scabra
  • H. villosa var. sierrablancensis, habit, flowering shoot (NM. Lincoln Co., type locale)
  • H. villosa var. villosa
  • H. viscida, habit (photo by S. McLaughlin), shoot (AZ. Cochise Co. Chiricahua Mts.)
  • H. zionensis; habit (near Zion N.P.; Kane Co. UT), habit (on "hotpots" in northern UT)

Last update 23 October 2005 by J.C. Semple        © 2002, 2004, 2005 J.C. Semple