Inflorescences

1. Inflorescences Spring 2013

2. What is an inflorescence? • Simpson = An aggregate of one or more flowers, the boundaries of which generally occur with the presence of vegetative leaves below • Judd et al. 2008 = The shoot system which serves for the formation of flowers and which is modified accordingly

3. Look for the flowering zone! (from Judd et al. 2008)

4. Inflorescence development Determinate: the apical meristem of the primary inflorescence axis terminates in a flower, which usually matures first with overall maturation from the apex to the base Indeterminate: the apical meristem of the primary inflorescence axis does not terminate in a flower but rather retains its meristematic potential, with maturation going from the base to the apex

5. Determinate inflorescences Fig. 9.35

6. scorpioid cyme cyme terminal & solitary head helicoid cyme

7. Indeterminate inflorescences Fig. 9.36

8. raceme spike spadix head panicle

9. Determinate or indeterminate types Also heads can be either. Fig. 9.37

10. Secondary or compound inflorescence types Fig. 9.38

11. Specialized inflorescence types Fig. 9.39

12. Fruits Spring 2013

13. Maturation • An inflorescence matures into an infructescence. • An ovary (simple or compound) matures into the fruit (but may include additional structures (e.g., hypanthium or perianth parts). • A fertilized ovule matures into a seed.

14. Ovary wall becomes the pericarp: • ENDOCARP – innermost layer • MESOCARP - middle layer • EXOCARP - outermost layer Each can be modified independently of the others (e.g., the endocarp can be stony, the mesocarp fleshy, and the exocarp leathery) or the pericarp can be of uniform color or texture. pericarp

15. exocarp mesocarp endocarp seed Avocado (Persea, Lauraceae)

16. Three main fruit groups • Simple fruit = a fruit that develops from a single flower • Aggregate fruit = develops from multiple separate carpels of a single flower • Multiple fruit = a fruit derived from the gynoecia of several closely clustered flowers

17. Simple fruits • Simple fruits = fruits developing from the gynoecium of a single flower (i.e., a single carpel or a compound ovary of 2 or more carpels); can be dry or fleshy

18. Dry Simple Fruits • Dry at maturity • Does fruit open (dehisce) or not? (Dehiscent versus indehiscent) • Number of carpels? Number of seeds? • Are any wings or other appendages present?

19. Indehiscent Dry Fruits Fig. 9.40

20. Achene: single-seeded, seed coat not fused to pericarp

21. Utricle – a bladdery or inflated achene with the pericarp larger than the seed

22. Caryopsis: “Grains”; singled-seeded, seed coat fused to pericarp; unique to grasses Wheat (Triticumaestivum) Maize (Zea mays)

23. Samara — a single-seeded, dry, winged indehiscent fruit Ulmus (Ulmaceae)

24. Dry Indehiscent Fruits: Nuts hard-shelled, one-seeded

25. Dehiscent Dry Fruits Fig. 9.41

26. Follicle: one suture opens Asclepias (Milkweed, Apocynaceae)

27. Follicles in the Ranunculaceae (buttercup family) http://tezalizard.blogspot.com

28. Legume: opens along 2 sutures Bean Family Fabaceae (Leguminosae)

29. Capsule: a dry fruit formed from 2 or more united carpels and dehiscing at maturity to release the seeds

30. Loculicidal Capsule Each carpel splits along the middle, opening directly into the locule

31. Septicidal Capsule The carpels separate along their side walls, or septa.

32. Poricidal Capsule Papaver (Poppy, Papaveraceae)

33. Capsule modifications In some plant families, capsules are modified in special, characteristic ways. Fruit and seed dispersal are still the guiding needs.

34. Cruciferous Dry Fruits Silique Silicle Mustard Family (Brassicaceae or Cruciferae) 2-carpellate, outer rim (replum), persistent partition (false septum)

35. Schizocarp of mericarps Dill (Apiaceae) samaroid mericarps Acer (Sapindaceae)

36. Fleshy Simple Fruits One or more layers of the pericarp become fleshy—which one(s)? Number of carpels? Number of seeds? From a superior or inferior ovary?

37. Fleshy Simple Fruits • Berry – Entire pericarp fleshy or exocarp may be leathery; one to many seeds • Drupe - Mesocarp fleshy, endocarp hard, exocarp variable; usually one seeded but can have multiple seeds • Pome – Fleshy mesocarp (mainly hypanthium tissue) and leathery or papery endocarp; derived from an inferior ovary (Rosaceae)

38. Berry Capsicum (Solanaceae)

39. Berry—other examples blueberries tomatoes tomato relatives bananas eggplants

40. Berry (Pepo) Found in the Cucumber Family (Cucurbitaceae): parietal placentation, leathery exocarp

41. Berry(hesperidium) Found in the citrus family (Rutaceae): Leathery exocarp, fleshy modified trichomes (juice sacs)

42. Drupe—stony endocarp

43. Drupe - Coconut Cocosnucifera (Arecaceae)

44. Pome Rose family (Rosaceae): inferior ovary, cartilaginous endocarp, fleshy hypanthial tissue

45. Three main fruit groups • Simple fruit = a fruit that develops from a single flower • Aggregate fruit = develops from multiple separate carpels of a single flower • Multiple fruit = a fruit derived from the gynoecia of several closely clustered flowers

46. Aggregate Fruit Rubus (Rosaceae)

47. Aggregate of Achenes

48. Aggregate of samaras

49. Three main fruit types • Simple fruit = a fruit that develops from a single flower • Aggregate fruit = develops from multiple separate carpels of a single flower • Multiple fruit = a fruit derived from the gynoecia of several closely clustered flowers

50. Multiple fruit of achenes Platanus (sycamore) A. Laurent