Phyllotaxy
Arrangement of leaves at the stem or branches is called Phyllotaxy.
NOTE 1. Reticulate venation of leaf of unuostate type is also called reticulate pin net while reticulate milticostate venation is also called reticulate palmate.
2. Parallel unicostate venation is also called parallel pinnate while parallel multicostate venation is also called parallel palmate.
Types of Phyllotaxy -
1. Alternate
2. Opposite
3. Whorled
1. Alternate -
only one leaf born at a node and next nodeit is born in opposite side so it forms two or more than two alternate row vertically example China rose , mustard.
2. Opposite -
Two leaves are born on the opposite sides of a single node.
It is of two types -
1. Opposite Superposed -
lives of all node develops in same plane so that only two row are formed on the stem example guava and jamun etc.
2. Opposite Decussate -
A pair of leaves at one node stands at right angle 90 degree to the next upper and lower pair of a leaf so that four vertical rows are formed on the stem. Eg , tulsi , aak.
3. Whorled -
More than two leaves at present on every node and arranged to form a circle or whorl.
Generally leaves of next Node are alternate so , that all leaves are exposed to sunlight example nerium devil tree.
Types of leaf -
1. Simple Leaf -
A leaf having single lamina with smooth or incised margins but the marginal incission is not a deep up to mid rib example mango, gawah, China rose, baniyan etc.
2. Compound Leaf -
In it the lamina is incised up to mid rib or petiole because of which lamina is divided into many parts called leaf let.
It is of two types
1. Pinnate Compound Leaf -
The incision of lamina are towards the midrib so that now midrib is called rachis.
The leaflets aaye present literally in a positive manner or alternately.
It may be of following types
1. Unipinnate -
Leaflets are directly attached with rachis.
If leaf lets are even in number then arrangement is called peripinnate. Eg, gram
If leaf lets are odd number then arrangement is called imperipinnate. Eg, rose , neem etc.
2. Bipinnate -
In it, rachis is again divided into branches called rachillae. So, secondary live let's are formed on the both side of rachillae. Eg, touch -me-not plant , babool ( acasia).
3. Tripinnate -
The rachillae is again divided and secondary leaf lets forms tertiary leaf lets.
Eg, moringa
4. Decoumpound -
In it , division of rachis occurs more than three time. Eg, dacccus carota. (Carrot).
(B) Palmate Compound Leaf -
The incission of a leaf margin reach to the tip of petiole like the fingers of palm.
It is of following type -
1. Unifolate -
In it, a single leaflet is a formed at the tip of petiole. Eg , citrus , Limon ( lemon ).
2. Bifolate -
It has two leaflets attached the petiole. Eg, bignonia , princepia etc.
3. Trifolate -
It has three leaflets attached at tip of petiole. Eg, bel ( aegle marmelos ).
4. Multifolate -
It has four leaflets for more than four leaflets. Eg , silk cotton ( bombax )
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