1. Roots, Stems, Leaves and Flowers are the Criteria.
Plant Identification
Roots, Stems, Leaves and Flowers are the Criteria.

2. Plant Identification
Many things are taken into consideration when trying to identify a plant.
Roots, stems, leaves and flowers will help in the identification process.

3. Terminology
In order to be able to identify a plant and put it in the right family, you need to know the terminology to use.

4. Plant Identification You have two main categories of plants.
Monocots – grasses, grain crops, lilies, gladiolas, and palm trees

5. Plant Identification
Dicots - most of the other plants such as the shrubs, trees, and flowers.

6. Plant Identification
The following sections (roots, stems, leaves and flowers) will show you how to use these for plant identification purposes.

7. Roots
The type of root will normally help you identify the plant. It will place the plant into a monocot or dicot category.

8. Types of Roots
Tap Root
Have a main central root and may have some lateral branching
E.g. Carrots

9. Types of Roots
Penetrate the soil to various depths - some only a few feet, others like the mesquite to as deep as 114 ft.

10. Types of Roots
Fibrous
Have many roots of equal size and a lot of lateral branching
Fibrous roots are generally much more diffuse and closer to the surface

11. Types of Roots
This root system can effectively prevent any other plant from becoming established – ex: grasses - idea of a healthy lawn is to compete with weeds

12. Types of Roots
Adventitious Buds - commonly develop on stems or roots - ex: stolons and rhizomes (Bermuda grass, cherry tree, Sumac and raspberry suckers)

13. Types of Roots
Prop Roots - augment regular roots for anchorage aid - ex: corn - roots come out above soil and help hold plant up

14. Types of Roots
Aerial Roots - extend down from the branches into the soil - ex: banyan trees
Pneumatophores- stick up from the mud for the purpose of absorbing oxygen – ex: cypress and mangrove

15. Types of Roots
Mycorrhizal fungi roots - form associations with soil fungi and act as root hairs increasing the absorption of water and minerals (symbiotic relationship - mutually beneficial) – found on trees in temperate forests such as pines and also on ferns, lettuce, white clover, perennial rye and orchids

16. Types of Roots
Haustorial - parasitic roots which not only anchor but also penetrate into the hosts vascular system for water and nutrients – ex: mistletoe

17. Types of Roots
Storage roots - starch and other molecules are stored for growth or flowering needs (ex: carrots, beets and turnips)

18. Types of Roots
Nitrogen fixing roots - members of the Leguminosae family (alfalfa, peas and clover) have a bacteria that infects their roots and forms nodules. The bacteria are able to fix atmospheric nitrogen, to a form, that the plant can use.

19. Why Different Types of Roots
All plants are in competition with each other for food and nutrients
By having different types of roots, the plants can reach different depths in the soil and still live side by side with other plants

20. Roots from Seeds – Monocot vs. Dicot
Tap Root
Seeds contain an undeveloped plant (embryo)
Seed germination - embryonic root (radicle) grows by dividing and elongation of cells

21. Roots from Seeds Forms one primary root
Ex: dicots (two leaves emerge from embryo), beans

22. Roots from Seeds cont.
Fibrous root
Embryos of grasses have a single radicle (root shoot)
Also has other embryonic roots (seminal roots) forming just above the radicle

23. Roots from Seeds cont. All of these branch to form the fibrous root
Ex: monocots (one leaf emerges from embryo)

24. Dicot Seed

25. Monocot Seed

26. Stems
Flowering plants - divided into two groups, monocots and dicots - stems have major differences in arrangement, distribution of tissues and appearance.

27. Stems
For identification: type of stem (woody or herbaceous), monocot or dicot, has pubescence (hair) or not (glabrous), shape of stem (square – round), or contains glands.

28. Monocot stem
Dicot stem

29. Mature Structure of Woody vs Herbaceous Stems
Lack secondary growth - because plants only live one year/growing season (annuals)

30. Mature Structure of Woody vs Herbaceous Stems
Stems remain soft and flexible.
Buds lack protective scales (don’t need to survive harsh conditions)

31. Mature Structure of Woody vs Herbaceous Stems
Woody stems
Plants living and growing over multiple seasons have secondary growth (xylem, phloem) increasing diameter of the stems

32. Specialized Stems
Adventituous stems – can be either rhizomes or stolons.

33. Specialized Stems
Rhizomes - underground horizontal stems (ex: perennial grasses, bamboo) - may also serve as a storage function (irises) – will grow a plant and roots at a node.

34. Specialized Stems
Stolons - runners - usually above ground, horizontal stems (really elongated internodes) – will grow a plant and roots at a node - ex: strawberries

35. Specialized Stems
Tubers - several internodes at the end of an underground rhizome (ex: potatoes) - eyes are axillary buds – where the tuber will grow a plant

37. Specialized Stems
Bulbs - large bud with small stem at lower end - storage in the form of numerous, fleshy leaves - ex: onion, lily, tulip
Corms - look like bulbs, but are mostly stem tissue with a few, papery leaves on the outside - ex: gladiolus, crocus

40. Leaves
Leaves are used as part of the identification process along with the roots and stems.
Look of the leaf (margins, venation, and shape), arrangement and whether it is monocot or dicot.

41. Leaves
Leaves may contain pubescence, glands or thorn like projections.
All of these points are considered when using a leaf for identification.

42. Parts of a Dicot Leaf
Leaf blade – expanded, usually flat portion of a leaf – contains chloroplasts
Petiole – connects the blade of a leaf to a stem or branch – holds leaf up for better air flow and to catch the light

43. Parts of a Dicot Leaf
Veins – threads of vascular tissue (xylem & phloem)
Node – place on a stem where leaves or branches normally originate
Stem – used for support of leaf

44. Where leaf would be attached to the branch or stem at the node.
Petiole
Veins
Leaf Blade
Dicot Leaf

45. Parts of a Monocot Leaf Node – where leaf arises or originates from
Blade – leaf blade – flat upper portion of leaf
Stem – used for support of leaf, inflorescence, and seed heads

46. Parts of a Monocot Leaf
Sheath – part of leaf that holds leaf to stem – encases stem
Ligule – membrane-like tissue extending up from the sheath (on inside) – keeps dirt and moisture out – clear membrane on leaf where attaches to stem

47. Monocot Leaf
Blade
Sheath
Node
Collar
Auricle
Stem
Ligule

48. Parts of a Monocot Leaf
Auricle – small appendages that extend out and sometimes around the stem – found at the junction of the blade and sheath – can be clasping or non clasping appendages

49. Parts of a Monocot Leaf
Collar – area between the leaf blade and sheath – auricles and ligules are on the inside of this area

50. Picture showing parts of a grass plant.

51. Differences Between Monocot and Dicot Leaves
Monocots – blade like leaf blade – wrap around the stem – no petiole – have main vascular bundles running parallel along length of leaf
Dicots – Have both a leaf blade and a petiole – single midrib (Vascular bundles) with branches

52. Two Types of Leaves
Simple leaves – composed of a single leaf and a petiole

53. Blade
Petiole
Simple Leaf

54. Two Types of Leaves
Compound leaves – are composed of a blade that includes several leaflets and a petiole – also contain a rachis (connects leaflets to the petiole) – two types:

55. Two Types of Leaves
Palmately Compound – (chestnut) – the lobes or divisions come together and are attached at one place at the base

56. Leaf Blade
Palmately Compound Leaf
Petiole

57. Two Types of Leaves
Pinnately Compound – compound leaf with the leaflets on two opposite sides, but off of one node – ex: ferns, ash, hickory

58. Leaflets
Leaf Blade
Pinnately Compound Leaf
Petiole

59. Leaf Arrangement
Monocots – have only one type of arrangement – leaf comes off of a node – ex: grasses and grain crops

60. Leaf Arrangement Dicots – flowering plants
Alternate – one leaf per node
Opposite – two leaves per node
Whorled – three or more leaves per node

61. Leaf Arrangements Whorl – look like helicopter blades – ex: Bedstraw
Alternate – one on each side of the stem, are not opposite of each other but every other one
Opposite – one on each side of the stem and opposite of each other

62. Arrangement of Veins Four types of vein arrangements:
Parallel veins – veins are small and run more or less parallel – most are long and narrow – ex: Buckhorn Plantain, grasses and Iris – mostly monocots

63. Arrangement of Veins
Netted veins – are large and small – the small ones connecting to each other to form a net – mostly dicots

64. Arrangement of Veins
Pinnately veined – with one larger midvein and smaller veins coming off along its length – mostly dicots

65. Arrangement of Veins
Palmately veined- with two or more large veins arising at or near the base of the leaf blade (palm) – leaves are usually broad or fat – mostly dicots

66. Parallel Veins
Netted Veins
Palmately Veined
Pinnately Veined

67. Monocot Leaf -Vein Arrangement
Dicot Leaf – Vein Arrangement
Smaller lateral vein
Midvein

68. Leaf Modifications
Tendrils – typically at the end of a compound leaf – enables plant to climb – ex: pea

69. Modifications
Stipules – occur at node where normal or true leaves arise from stem – are small leaf like structures at the base of petioles – may be leaf -like or spines (ex: locust)

70. Modifications Spines – modified leaves – ex: cactus
Awn – on reproductive structure in grasses – extension of the lemma portion of the flowering structure

71. Modifications
Bracts – floral leaves that form at the base of a flower or flower stalk
Cotyledon – the embryo leaf in a seed - first leaf of a seedling – used for food storage

73. Flowers
Petals – are highly colored portions of the flower.
May contain perfume (rose) or nectar glands –to attract pollinators.
Number of petals on a flower is often used in the identification of plant families and genera.

74. Flowers Dicots –have sepals and/or petals in multiples of four or five
Monocots – have sepals in multiples of threes

75. Parts of a Flower
Sepals
Petals
Stamens (anther & filaments)
Pedicel
Pistil (stigma,style & ovaries)

76. Parts of a Flower
Pedicel
Sepals
Receptacle

77. Types of Inflorescence (Flowers)
Raceme – inflorescence with the flowers single on pedicels (stems) arranged along an elongated stem (rachis – this is the stem that is between the flowers) – alternate – oldest are at the bottom and the youngest are at the top. Ex: snapdragon, foxglove

78. Types of Inflorescence (Flowers)
Umbel – flat-topped inflorescence with the rachis non-existent. Ex: wild carrot, dill

79. Foxglove
Snapdragon
Raceme

80. Dill
Umbel

81. Types of Inflorescence (Flowers)
Spike – type of inflorescence with the flowers sessile (without a stalk) along the rachis. Ex: gladiolus
Head – a dense cluster of sessile or nearly sessile (no stalk) flowers on a very short rachis. Ex: sunflower, clover

82. Spike
                    
Gladiolus

83. Clover
Sunflower
Head

84. Types of Inflorescence (Flowers)
Panicle – inflorescence with two or more flowers on each branch which are attached to a rachis (elongated stem). Ex: wild oats, downy brome
Corymb – is made up of florets whose stalks and pedicles are arranged at random along the stalk in such a way that the florets create a flat, round top. Ex: yarrow

85. Wild Oats
                                        
                                        
Downy Brome
Panicle

86. Corymb