1. Asterids: Asteraceae

3. 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

4. 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

5. 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.

6. Floral Formula

7. Asteraceae – World-wide

8. Typical Asteraceae Flower

10. Cross-section of Asteraceae Flower

11. More detail on disk flower

12. Note the chaff – bracts below each individual flower

13. Fruits are achenes

14. Sunflower “seeds” = achenes

15. Echinacea sp. – praire cone flower

16. Liatris flowers

17. Close-up of achene fruit with pappus

18. Taraxacum officinale

19. Close-up of Taraxacum head

20. Taraxacum fruits

21. Close-up of Taraxacum flower

22. 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.

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

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

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

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

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

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

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

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

31. Pappus: modified calyx

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

33. 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

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

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

36. Heliantheae

37. 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 resin Chrysothamnus (Rabbitbrush or chico)
Another important genus is Erigeron aka fleabane daisy

38. Chyrsothamnus sp. rabbitbrush

39. Erigeron elatior

40. 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

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

42. Chrysanthemum

43. Achillea millefolium - yarrow

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

45. Senecio triangularis

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

47. Pussytoes in Gnaphalieae

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

49. Gutierrezia sarothrae – broom snakeweed

50. Liatris punctata

51. Dandelion Subfamily - Cichorioideae
The Dandelion Subfamily
Strap shaped ligulate “petals”
No tubular flowers
Dandelions (Taraxacum)
Lettuce (Lactuca)
Includes Cardueae Tribe

52. Lactuca serriola – prickly lettuce

53. Tribe Cynareae or Cardueae (in your book) – Artichoke Tribe
Head inside a cluster of tightly compressed bracts
Like an artichoke, which is in this tribe, we eat the bracts!
No ligulate flowers
Many bristles on receptacle (spines inside artichoke)
Many thistles are in this tribe, Cirsium and also knapweeds, Centaurea
Cynara is artichoke
Name for genus Carduus

54. Artichoke - Cynara scolymus

55. Cirsium scariosum

56. Cirsium arvense

57. Argyroxiphium sandwicense, Silversword endemic toMaui

58. Argyroxiphium sandwicense, Silversword Maui