1 / 58

Asterids: Asteraceae

Asterids: Asteraceae. Asterids. Very large, diverse group 10 orders, many families Apomorphies: iridoid compounds sympetalous corolla ovules: one integument and the megasporangium is generally one cell thick. Asteraceae. Probably the most evolved of the families Two types of flowers

mateo
Download Presentation

Asterids: Asteraceae

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Asterids:Asteraceae

  2. Asterids • Very large, diverse group • 10 orders, many families • Apomorphies: • iridoid compounds • sympetalous corolla • ovules: one integument and the megasporangium is generally one cell thick

  3. Asteraceae • Probably the most evolved of the families • Two types of flowers • Ray • Disk • Herbs in our area, but can be trees in tropics • Very diverse: 19,000 species world-wide • Many flowers on the head inflorescence • Old name is compositae – b/c a composite of flowers

  4. Asteraceae • Inflorescence a head (capitulum): (usu.) many flowers arising from a compound receptacle, subtended by inflorescence bracts: involucral bracts or phyllaries, collectively termed the involucre. • Calyx modified as pappus. • Fruit an achene.

  5. Floral Formula

  6. Asteraceae – World-wide

  7. Typical Asteraceae Flower

  8. Cross-section of Asteraceae Flower

  9. More detail on disk flower

  10. Note the chaff – bracts below each individual flower

  11. Fruits are achenes

  12. Sunflower “seeds” = achenes

  13. Echinacea sp. – praire cone flower

  14. Liatris flowers

  15. Close-up of achene fruit with pappus

  16. Taraxacum officinale

  17. Close-up of Taraxacum head

  18. Taraxacum fruits

  19. Close-up of Taraxacum flower

  20. Five types of heads: 1) discoid, with only disk flowers; 2) disciform, with central disk flowers and marginal, eligulate female flowers; 3) radiate, with central (bisexual or male) disk flowers and peripheral (female or sterile) ray flowers; 4) ligulate, with all ray flowers (typically with 5-toothed corolla apices); 5) bilabiate, with all bilabiate flowers.

  21. Bilabiate flower posterior lip anterior lip Acourtia microcephala Trixis californica

  22. Ray flowers (heads ligulate = all rays) ligulate corolla Rafinesquia neomexicana Malacothrix californica

  23. Disk flower: heads discoid disk corolla Palafoxia arida Chaenactis gabriuscula Psathyrotes ramosissima

  24. Disk flowers: heads disciform(2 types of disk fls., same or different heads) male heads female heads Ambrosia chamissonis

  25. Heads radiate: inner disk & outer ray fls. disk flowers ray flowers Xylorhiza orcuttii Encelia farinosa

  26. Some heads are "chaffy" ovary disk flower Encelia californica chaff : bracts subtending flowers

  27. Involucre morphology two whorls many whorls one whorl Senecio vulgaris Coreopsis maritima Encelia californica

  28. Involucre morphology Phyllaries spiny & squarrose Phyllaries spiny Circium vulgare Silybum marianum

  29. Pappus: modified calyx

  30. Pappus: modified calyx beak capillary bristles, borne atop "beak" capillary bristles: barbellate capillary bristles: plumose

  31. Asteraceae • Because the family is so large, it is divided into two Subfamilies which are then divided into tribes: 12 to 17 in the whole family • Aster = Subfamily Asteroideae • Six tribes we’ll see • Dandelion = Subfamily Cichorioideae • One tribe

  32. Tribes of the Aster Subfamily • Heliantheae • Asterae • Anthemideae • Senecioneae • Gnaphalieae • Eupatorieae • Cynareae

  33. Tribe Heliantheae – Sunflower tribe • Opposite leaves • Very resinous • Bracts attached to individual flowers (chaffy receptacle) • Both types of flowers • Sunflower (Helianthus) and Echinacea

  34. Heliantheae

  35. Tribe Asterae – Aster Tribe • No bracts at the bottom of individual flowers • Example is genus Aster, generally fewer than 20 “petals” or ligulate flowers • Similar to above tribe, but without resinChrysothamnus (Rabbitbrush or chico) • Another important genus is Erigeron aka fleabane daisy

  36. Chyrsothamnus sp. rabbitbrush

  37. Erigeron elatior

  38. Tribe Anthemideae – Chamomile Tribe • Multiple layers of phyllaries of different lengths • Richly aromatic • Thin, dry, and translucent (i.e. scarious) bracts surrounding the flower base • Artemisia (sagebrush is in this tribe) • Achillea, Chrysanthemum

  39. Involucre morphology two whorls many whorls one whorl Senecio vulgaris Coreopsis maritima Encelia californica

  40. Chrysanthemum

  41. Achillea millefolium - yarrow

  42. Tribe Senecioneae – Senecio or Groundsel Tribe • Silky pappus around each flower • Pappus is usually pure white and very abundant • Usually naked receptacle • Senecio

  43. Senecio triangularis

  44. Tribe Gnaphalieae – Everlasting Tribe • Also has scarious bracts around flower base • No ligulate flowers, only tubular flowers • Example is cudweed or everlasting (Gnaphalium)

  45. Pussytoes in Gnaphalieae

  46. Tribe Eupatorieae – Boneset Tribe • “Baseball bat stigmas” • No ligulate flowers • Usually naked receptacle • Snakeweed, Gutierrezia • Liatris, common ornamental

  47. Gutierreziasarothrae – broom snakeweed

  48. Liatrispunctata

More Related