1. S.Y.BSc SEMESTER III BOTANY PAPER I UNIT: III INFLORESCENCE
By Miss. Shweta Chavan
DEPARTMENT OF BOTANY
SATISH PRADHAN DNYANASADHANA COLLEGE,THANE(W)

2. Saucer Magnolia solitary flowers
Some species of plants produce solitary flowers.
Solitary flowers are are borne singly and separate from one another.
Saucer Magnolia solitary flowers

3. Many solitary flowers on Bloodred Geranium (Geranium sanguineum)
Another example of a plant that bears solitary flowers is Bloodred Geranium.
Many solitary flowers on Bloodred Geranium (Geranium sanguineum)

4. What is an inflorescence?
The stem axis of the floral region bearing a group of flower in a particular manner.
There are many types of inflorescences. Each type of inflorescence is determined by how the flowers are arranged.
Inflorescences are a useful plant ID tool.

5. Parts of Inflorescence
Peduncle: central axis on which flowers are produced
Pedicel: stalk of single flower, pedicillate or sessile
Bract: reduced leaf at the base of flower
Receptacle: flat disc like peduncle axis

6. Types of inflorescence
Racemose: Inflorescence axis continues to grow & give off flowers. The older flowers are at the base and younger at the apex
Types of racemose:
Simple raceme: with elongated axis
Raceme: flowers are stalked, lower flowers with long stalks eg Cesalpinia
Spike: flowers are without stalk, e.g. Tuberose
Catkin: spike with long and pendulous axis with unisexual flowers
Spadix: spike with fleshy axis, enclosed in bright coloured bracts (spathe), e.g. colocasia

8. rar

11. Spike Individual flowers are sessile (without pedicels).
Lower flowers open first.
Indeterminate.
spike

12. Raceme Individual flowers have pedicels.
Pedicels can vary in length from species to species.
Lower flowers open first.
Indeterminate.
peduncle
pedicel
raceme

13. Raceme with shortened main axis

15. Raceme with shortened main axis
Corymb: short main axis, lower flowers with longer stalks than upper ones, so all flowers are at same level, e.g. Cassia
Umbel: flowers with more or less equal stalk, flowers spread out from a common point. Presence of bract forming involucre at the base, e.g. Centella

16. Raceme with flattened main axis
Capitulum (head): main axis flat, bearing mass of small flowers (florets), with whorl of bract at the base. Flowers – unisexual ray and bisexual disc florets, e.g. Sunflower, cosmos, gerbera

17. Compound raceme
Panicle: axis is branched, flowers are produced on lateral branches, e.g. gulmohar
Compound corymb: peduncle is branched and each branch bear corymb like inflo. E.g. Ixora
Compound umbel: shortened prim axis with flowerson the branches, e.g. coriander
Compound spadix: more than one spadix inflo. Enclosed in bract
Compound head: peduncle is branched, several capitula in the same involucre,

18. Cymose infloresence
Main axis and lateral axis end in a flower, the growth of the axis is definite. Terminal flower is older than lateral flowers.
Types of cymose
Uniparous (monochasial) cyme: main axis is terminated into flower with only one lateral branch ends with flower
Helicoid: lateral axis develop successively on same side forming helix, e.g. Hamelia
Scorpoid: lateral axis on alternate side forming zig-zag structure, e.g. Heliotropium

19. Types of cymose inflorescence
Biparous (dichasial): mature flower at the tip of main axis, two lateral younger flowers, e.g. clerodendron, jasmine
Multiparous (polychasial): older flower at the tip of axis, number of lateral flowers around, like umbel,e.g. Ixora, Calotropis

21. Panicle
A highly branched inflorescence consisting of many, repeating units.
Panicles can be made of many spikes, racemes, corymbs, or umbels.
Indeterminate.
A panicle of racemes

22. Umbel
Individual flower pedicels all originate from the same spot on the peduncle.
Outer flowers open first.
Indeterminate.
pedicel
peduncle

23. Umbel Allium ‘Jade Eyes’, image courtesy of Breck’s.
Often, umbels are globe-shaped like this one.
Allium

24. Corymb Somewhat similar to the umbel.
Individual flower pedicels are attached to the peduncle at different points.
Often flat-topped.
Outer flowers open first.
Indeterminate.
peduncle
pedicel
corymb

25. Corymb
Pyrus calleryana, Callery Pear, is a beautiful, spring-flowering tree covered with corymbs of white flowers.
Callery Pear

26. Cyme In real life, cymes tend to be flat or convex shaped.
The inner flowers open first.
Determinate.
cyme

27. Cyme
Cymes are often compound as shown in the illustration to the right.
compound cyme

28. Corymbs vs. Cymes
Often these two types of inflorescences can look a lot alike.
Remember that corymbs are indeterminate, they continue to elongate as the season progresses. Cymes are determinate and do not continue to elongate as the growing season progresses. Also, the inner flowers of cymes open first.

29. Composite Head A highly advanced inflorescence.
disk flower
A highly advanced inflorescence.
Consists of separate ray and disk flowers
Bracts may be green, but can also be colored(Strawflower).
ray flower
bract

30. Composite Head
Helianthus annus, Sunflower, produces a large composite head.
After pollination and fertilization, each disk flower becomes a single-seeded fruit.
Sunflower

31. Composite Head
Echinaceae purpurea, Purple Coneflower (image courtesy of Wildflower Farm).
Composite head with purple ray flowers and brown disk flowers.
Purple Coneflower

36. Review Time!

37. What’s this?
Umbel

38. What’s this?
Raceme

39. What’s this?
Corymb

40. What’s this?
Composite Head

41. What’s this?
Panicle

42. What’s this?
Spike

43. What’s this?
Cyme

44. THANK YOU…….