Question

In examples of interpetiolar stipules, the number of leaves and stipules at each node are
A. One and two
B. Two and two
C. Two and one
D. One and one

Answer 1

Leaves are the food manufacturing system of the plant. All food used by living organisms of all kinds are products of leaves and other green plants. Leaves are the most important appendages of aerial plants.
A leaf is a lateral flattened, green structure that grows on a node. Though occasionally they are needle-like structure or scale like structure.

Complete answer:
The green food making leaves of plants are termed foliage leaves. Typical foliage leaves consist of leaf stalk or petiole, the expanded portion at the end of the petiole is called blade or lamina. Leaf base is the lowermost part of a leaf by which the leaf is attached with a node.
Stipules are outgrowth on either side of the base of a leafstalk. However, in some species stipules are absent.
Position of stipules on a plant varies.They are commonly found in dicotyledons, where they appear in pairs alongside each leaf. Some monocotyledon plants display stipule-like structures, but only display one per leaf.
Purpose of stipules:
Stipules have various functions. Some stipules are not well understood or may be vestigial.
Foliaceous stipules are used like leaves to make energy for plants.
Stipules protect the next leaf or bud as it grows in then falls off after the leaf unfolds.
Stipules can be used as climbing tendrils by climbing plants.
Spiny stipules can be used to help protect the plant from animals.

Types of stipule:
Lateral: Present laterally on or at the side of the base of petiole. Example: Hibiscus.
Adnate: Present as wings due to their fusion with the petiole. Example: Rosa.
Scaly: Present as a dry, small, membranous structure. Example: Spergula.
Intrapetiolar: Present in axil of leaf and their margins fuse above the petiole. Example: Gardenia.
Interpetiolar: Present in between petioles of opposite or whorled leaves. Example: Mussaenda.
Foliaceous: Present in the form of a large leaf. Example: Lathyrus aphaca
Ochreate: Present in the form of a tubular sheath round the internode. Example: Polygonum
Spinous: Present in the form of hard spines. Example: Acacia nilotica
Tendrillar: When the stipules modify in the form of tendrils. Example: Smilax
Ventral: Present on the ventral side of petiole. Example: Magnolia

Interpetiolar stipule is a stipule which is located on the stem between the petioles of opposite leaves. It is formed because of the fusion of two stipules of opposite leaves. The numbers of leaves present at each node are one and the number of stipules at each node is two. Example: Coffee plant.

Thus, the correct answer is A, one and two.

Note: The arrangement of leaves on stem or branch is called phyllotaxy. The main aim of phyllotaxy is to orient the leaves in a way that they receive maximum sunlight to perform the function of photosynthesis. It is of two types: Alternate or spiral and opposite.
Main functions of the leaves are photosynthesis, transpiration and gaseous exchange. They also function as storage of food, water stored in leaves of succulent nature. It also helps to reduce the rate of transpiration.