Lab#2

Ca oxalate crystals

• Has a great importance in identification and differentiation of different plants

• Formed in plants to get rid of excess calcium salts where it reacts with oxalic acid formed by metabolism of CHO

• Ca- oxalate crystals precipitate in different shapes and sizes

Ca oxalate crystals:

• Prisms: ( e.g Quillaia)• Clusters (rosettes) (e.g Rhubarb)• Crystals sheath (e.g Senna)• Clusters (e.g Datura)• Raphide (e.g Squill)• Microsphenoidal (sandy) (e.g Atropa

belladonna)• Twins (e.g Hoscyamous)

Stomata

• Stomata:

Each stomata consists of tow guard cells which guards the ( osteole)

Stomata

According to the epidermal cells surrounding these guard cells:

• Anomcytic type:In which stomata is surrounded by same epidermal

cells (e.g Digitalis leaf )• Anisocytic type:In which stomata is surrounded by 3 or 4

epidermal cells one is smaller than otherse.g: Datura Belladonna Hyoscyamous

Stomata

• Paracytic type:

The axis of tow guard cells parallel to osteole ( senna)

• Diacytic type:

The 2 guard cells are located transversely to the central line of the osteole

( mentha)

Pollen grains

• Spiny pollen grains:

Pyrethrium

• Triangular:

clove

Trichomes (hair)

Trichomes

Non- glandular Glandular

Non glandular hair

• Simple unicellular hair– Formed of one cell

• e.g senna ( warty cuticle hair)• e.g cannabis (Cystolith hair )

• Multicellular hair:a. Uniseriate (formed of one row) e.g datura

stramoniumb. Collapsed and twisted e.g Digitalis Pyrethrium T-shaped

Glandular hair

• Unicellular head- unicellular stalk

e.g Digitalis

• Multicellular head- multicellular stalk:

e.G digitalis Shaggy hair

Glandular hair

• Multicellular head- unicellular stalk

e.g Digitalis

e.g Mentha (Labiaceous hair)

• Branched hair

e.g Hyoscyamous