taxonomy terminology

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. 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. Solitary Flowers
• 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.
raceme
pedicel
peduncle

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.
peduncle
pedicel

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.
corymb
pedicel peduncle

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.
• Consists of separate ray
and disk flowers
• Bracts may be green,
but can also be
colored(Strawflower).
ray flower
disk 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…….