Part 1
PREFACE This book is the result of several years’ experience of the authors with the Intermediate classes. A lot of time is usually wasted in giving instructions and notes to the students as to the procedure of the day’s work. The authors feel that this humble attempt at systematizing the practical work of Intermediate classes, will goa long way to remove this difficulty. The Syllabus of the Punjab University has been strictly followed in this scheme. The authors take this opportunity to thank Professor Mehr Chand Sethi, M. Sc. Professor of Botany, Forman Christian College, Lahéte, fSce hig valuable guidance and assistance. Their thanks are also due to Professor Ganga Kam Kohli, M. Sc., Dyal Singh College, Lahore, and Professor Jiwan Singh, M.Sc., Khalsa College, Amritsar, for their helpful criticisin of the manuscript. Amritsar, H.C. DASS 1934. C. L. SAWHNEY CONTENTS Equipment , Parts of the Plant Morphology of the Seeds Germination of the Seeds Morphology of the Stem Morphology of the Root Morphology of the Leaf Morphology of the Flower Types of Inflorescences Morphology of the I‘ruits Apparatus for the Study of Histology Histology a Histology of the Stem Histology of the Root Histology of the Leaf Histology of the flower Key to the Natural Orders Study of Natural Orders Parasitic Plants Insectivorous Plants Algae Fungi Bryophytes Pteridophytes Gymnosperms Physiology Page 96 98 100 102 130 132 13+ 136 138 1+4 152 156 EQUIPMENT The student should provide himself with the following things for practical work in Botany :— 1. A drawing pencil and an eraser. 2. <A set of instruments comprising the following :-— (a) Scalpel (large and small) (b) Forceps (large and small) (c) A couple of mounted needles. (d) A pocket lens. PARTS OF THE PLANT. Uproot a small sunflower plant from a flower pot and note the following parts :— 1. Root System: The lower part of the plant axis consists of a main root, bearing smaller roots upon it. Note that the main root and the smaller roots are not coloured, and together constitute the Root-system, which serves to fix the plant in the ground and also to absorb water from the soil. 2. Shoot, Stem and Leaves: The aerial parts of a plant, as a whole, constitute the shoot. The branched axis of the shoot is the stem, and the broad green appendages borne on the stem are the leaves. The leaves are the kitchens of the plant where its food is cooked. The energy of the Sun’s rays serves as the fuel. The stem and its branches function, firstly to conduct to the leaves, the raw food material absorbed by the roots, and secondly to bear the leaves so as to expose them well to the sun. 3. Axil, Axillary: The angle between the stalk of a leaf and the stem is known as an axil. Note a small projection-like bud in the axil. It will later develop into a lateral branch. The bud is known as axillary. Note other axillary buds at various stages of development. 4, Terminal Bud: At the extreme end of the stem is a compact structure formed by the overlapping of the young, unfolded leaves. Lying protected amidst these young leaves is the growing pcint of the stem. The whole structure is called the terminal bud. 5. Flowers: The flowers of the sun-flower plant are rather small and aggregated together into compact groups. The flowers form seeds, which are capable of forming new plants of the same type. The flowers are the reproductive parts of a plant. MORPHOLOGY OF THE SEEDS. To prepare the seeds for study, soak them in water overnight. 1. Seed of Almond: A single seed is found within a hard fruit part. The seed has a brown seed-coat or testa, and a white, thin membrane called tegmen within it. On the removal of the seed-coat and tegmen come to view two white masses, the cotyledons, wedged between and attached to which is a small embryo. It consists of a radicle, projecting out from between the two cotyledons, and a leafy shoot or the plumule. The two cotyledons are attached to the axis of the embryo by small stalks, and are in fact the first two leaves of the embryo. They serve for storage of food material. 2. Seed of Water-melon: The seed has a hard, black or red testa. On its re- moval, note the same structures as in the seed of almond. 3. Seed of Pea: At one end, on the surface of the testa, there is a prominent, narrow scar, marking the point of attachment in the fruit, known as the hilum. Very close to it is a small aperture, the mzcropyle, from which a drop of water oozes out, if a soaked seed is pressed. Enclosed within the testa are two massive cotyledons and a small embryo. 4, Seed of Gram: The seed is somewhat conical, tapering abruptly to a sha:p point. Note a conspicuous scar-like hilum and a micropyle lying between the hilum and the pointed end of the seed. emove the black or brown testa and note the parts as in the seed of Pea. 5. Seed of Castor-oil: The testa is very hard and spotted and bears a swollen, glandular outgrowth at one end, the aril, which absorbs water and helps to break the hard testa. Tegmen is also present’ After the removal of the seed coat, you come across a white mass of food material, the endosperm. Split the endosperm longitudinally into two and note an embryo and two thin leaf-like cotyledons. The radicle is blunt and knob like. The cotyledons in this seed do not serve for storage, the seed is albuminous. 6. Maize Grain: Each grain is somewhat conical and flattened on two surfaces where it has been in touch with the other grains on the cob. The maize grain is a fruit, enclosing a single seed. . The fruit wall or the pericarp is fused with the testa of the seed. Note oblong white areas on the flat surfaces of the seed. Place the seed on one of its flat surfaces and give a cut at right angles to this surface, passing through the conical end. Note that the narrow end is occupied by a massive embryo consisting of a radical and a plumule, wrapped in several sheaths. The whole upper white area is the endosperm. The outer layer of the endosperm, next to the fused testa and pericarp, is the aleurone layer. Note a single membrane-like cotyledon, the scutellum, between the embryo and the endosperm. It serves as an absorbtive organ. GERMINATION OF THE SEEDS. Place a few seeds, (of Water-melon, Gram, Castor-oil and Maize) covered with moist saw dust, ina dish. They begin to germinate in two or three days. 1, Water-melon. Note that the radicle elongates and is the first to emerge out, breaking through the seed-coat, at the pointed end of the seed. It forms the main or the primary root. Note that the cotyledons are epigeal, 1. e¢., they are lifted above the ground, and become green. The part of the axis below the cotyledons shows very active growth and is called the hypocotyl. It is curved in young seedlings. The plumule unfolds its branches and _ leaves. 2. Gram. The radicle breaks through the softened testa and goes deep into the soil. The hypocotyl remains curved for some time, to protect the delicate parts of the plumule against the friction of the soil, but straightens up gradually, as it grows. The cotyledons are not taken up above the ground and are termed hypogeal. 3. Castor-oil. The hypocotyl forms a prominent arch. The leafy cotyledons remain within the seed for some time, but enlarge and come out, as the hypocotyl straigh- tens, to form the first batch of the green leaves. 4, Maize. The radicle and the plumule pierce through the fused pericarp and testa in opposite directions. The scutellum is hypogeal. Note that the axis is not curved ; the plumule is pointed like a lance and is able to pierce the soil successfully. In advanced stages of germination, a number of small roots may be seen arising from the base of the shoot. MORPHOLOGY OF THE STEM. I. Buds: 1], Examine the terminal portion of a shoot of Banyan or Pipal. Note the st0des or the places from where the leaves arise, and the internodes or the leafless stretches of the stem. One leaf arises from each node. There are two scars, one on each side of the insertion of the leaf stalk on the stem. This is from where the stipules have fallen off. The stipules can be seen in the leaves of the terminal bud. Note that they are large, brown or purple in colour, and cover the comparatively small and young leaves. Remove them one by one to see their arrangement. Cut a transverse section of the terminal bud with a sharp razor and note the arrange- ment of the overlapping leaves and their stipules. 2. Examine a branch of Pear or Peach before the floral season and note the winter buds. 12