R.H. Whittaker (1969) proposed 5 kingdom classification. Plantae is the 4th in it. Plantae includes eukaryotic, generally multicellular, green, autotrophic with cellulosic cell wall.
Plantae are divided into
1) Cryptogams 2) Phanerogams
Cryptogams are non-flowering which include Algae, Bryophytes and Pteridophytes. Phanerogams include flowering plants or spermatophytes which include Gymnosperms and Angiosperms.
These are less known to students. But they are very important in some aspects.
What are Algae?
Unicellular or multicellular, microscopic or Macroscopic eukaryotic, green, autotrophic, thalloid, branched or unbranched, haploid, gametophitic, non-vascular, fresh water or marine aquatic plants.
The study of Algae is called Phycology or Algology. Fritsch is 'Father of Phycology' and M.O.P. Iyengar is called father of phycology in India.
Where these algae live?
They show more variations in habitat.
Fresh water: Most of the green algae live in fresh water, either in stagnant or running water.
Marine: Most of the Brown algae and Red algae live in sea water.
Terrestrial: Some algae like Vaucheria, Fritschiella grow well in moist, aeriated, fertile soils.
Cryophytic: Algae like chlamydomonas live in snow or ice.
Epizoic: Some algae like cladophora crispata live on the body of turtles.
Endophytic: Algae like Anabeena (Azolla leaves Cycas coralloid roots), Nostoc (Anthoceros thallus, cycas coralloid roots) show endophytic habitat.
Epiphytic: Oedogonium, Bulbochaete, cladophora and vaucheria show epiphytic habitat.
Endozoic: Zoochlorella lives inside the body of Hydra or sloth bear.
Symbiotic: Members belonging into chlorophyceae etc live in symbiotic relationship with fungi belonging to ascomycetes or Basidiomycetes and form lichens.
Parasitic: Algae like Cephaleuros lives as a parasite on the leaves tea and coffee plants.
Moist stones: Some algae live on moist stones.
Moist wood: Some algae live on moist wood also.
In how much space they live?
They occupy most of the space on the earth as 3/4 of it is water.
They perform 90% of photosynthesis and thus comprise highest level in producers.
Are All Algae Alike?
No. They are divided into several classes, 3 of them are important. This division is based on 1) Substances in the cell 2) Pigments 3) Reserved form of food.
2) Phaeophyceae and
It is the largest class. These are also called Green algae. The plant body is called thallus. Basing on thallus organisation
1) Unicellular motile e.g.: Chlamydomonas
2) Unicellular non - motile. e.g.: Chlorella
3) Colonial: Many cells of similar structure and shape live together as a single definite number of plant. Ex: Volvox (motile), Scenedesmus (non - motile)
Filamentous unbranched: These are multicellular, uniseriate, filamentous and unbranched. e.g.: Spirogyra, Ulothrix.
Cell wall: It is made of cellulose, and pectin. Pectin dissolves in water and forms nucilage.
They include Chl a, Chl b. They are present in chloroplasts. Chloroplast may be 1 (Chlamydomonas, Chlorella), 1 - 16 (Spirogyra) or many (Cladophora).
The shape of the chloroplast may be cup like (Chlamydomonas) star or stellate (Zygnema), ribbon like (Spirogyra) or discoid (Cladophora) girdle shaped (Ulothrix). The characteristic feature of chlorophyceae is the presence of pyrenoids in chloroplasts.
Pyrenoids are made of protein core which store starch in the form of layers around it.
The algae store food in the form of starch in pyrenoids some algae store food in the form of oil drops.
It generally occurs by fragmentation. Rainy season is the favourable season. It also may occur by fission in unicellular forms.
It occurs by aplanospores (Spirogyra), akinetes (Spirogyra) or Zoospores. Zoospores are produced in Zoosporangium. The sporangia are unicellular. Spores are biflagellated. Flagella are apical in position.
It occurs by the formation of gametes. Gametes may be motile (biflagellated in Ulothrix, Cladophora, Chlamydomonas) or non-motile (aplanogametes in Spirogyra). Gamates are produced in gametangia. These are unicellular. Male gametangium is called Antheridium and female is called Oogonium. The same in Chara are called Nucule and globule respectively.
Sexual reproduction may be isogamy, anisogamy or oogamy.
The gametes may be non - flagellated and isogamous (Spirogyra) flagellated isogamous (Chlamydomonas)
It may be anisogamous i.e., fertilisation occurs between flagellated dissimilar gametes. (e.g.: Chlamydomonas)
It may be oogamous i.e. union occurs between flagellated smaller male gamete and larger non-flagellated female gamete. e.g.: Chlamydomonas, Volvox, Chara,
Life cycle: It is haplontic (i.e. all stages in the life cycle are haploid except Zygote) meiosis occurs in Zygote.
These are also called Red algae. It is one of the most economically important class.
Most of the members live in sea water (marine) or brackish water. Batrachospermum lives in fresh water. They prefer warmer areas. They occurs in both higher light intensity regions close to the surface of water and also a great depths in oceans.
These are multicellular, filamentous with complex organisation.
e.g.: Batrachospermum, Polysiphonia, Porphyra. Porphyra is parenchymatous and bears fronds.
It is made of Cellulose, Pectin and Polysulphate esters. Cells are inter connected by pit connections.Cell wall of Gracilaria and Gelidium consists a polysaccharide called agar agar.
They include Chl a, Chl d and Phycoerythrin. The plants are red due to the presence of water soluble. Phycobilin pigments called r - Phycoerythrin and r - Phycocyanin.
Plants store floridean starch (similar to amylopectin and glycogen)
Flagellated bodies: Absent
Vegetative reproduction: It occurs by fragmentation.
Asexual reproduction: It occurs by non flagellated spores
Sexual reproduction: Flagellated gametes are absent. It is oogamous type. Male sex organ is called antheredium or spermatangium. Female sex organ is called Carpogonium and it is flask shaped Fertilisation is internal. Post fertilisation changes are complex. Cystocarp (fruiting body) is produced.
It is haplobiontic or diplobiontic.
It is also called brown algae.
Habitat: Mostly they live in brackish water and salt water (marine). Rarely they also live in fresh water.
Habit: These are macroscopic. Generally they are called Kelps. They even grow upto 100 metres. Largest in Macrocystis.
e.g.: Laminaria, Fucus, Ectocarpus, Dictyota, Sargassum etc.
Sargassum is in North Atlantic Ocean and covers thousands of acres. This area is called Sargasso sea.
Cell wall: It is made of cellulose and Algin (gelatinous).
Pigments: These are present in chloroplasts or chromatophores. Pyrenoids are also present. The pigments include Chl a, Chl c, Carotinoids and Xanthophylls. The plants vary in colour from olivegreen to various shades of brown depending on the amount of Fucoxanthin.
Storage food: They store food in the form of Laminariun and Manitol
Laminariun is a complex carbohydrate. Manitol is an alcohol.
Vegetative Reproduction: It occurs by fragmentation. It may be due to accidental breakage or by death and decay of older parts.
Asexual Reproduction: It occurs by pyramidate or pyriform or pear shaped zoospores. These are biflagellated position of the flagella is lateral. Flagella are unequal.
Sexual Reproduction: It occurs by the formation of gametes. The gametes are pyriform and biflagellated. Position of the flagella is lateral. It may be isogamous or axisogamous or oogamous type. Male and female sex organs are in some are differentiated.
Life Cycle: The life cycle may be diplontic (Fucus) or haplodiplontic (Ectocarpus, Laminaria)
Thalloid, Branched, Parenchymatous, green, autotropic, haploid, gametophytic, prostrate or erect, first, archegoniate, embryophytic, highly advanced, non - vascular, Cryptogamic primitive land plants. The study of Bryophytes is the term Bryophytes was coined by Braun (1864) called bryology.
Habitat: S.R.Kashyap is known as father of Indian Bryology. They grow on moist soil, damp, humid and shaded localities. They are poorly adapted to land habitat. They require water for sexual reproduction. Hence they are also called Amphibians of plant kingdom.
These are divided into 3 classes. The name of the class ends with - Sida.
The members are called liverworts as the branches resemble the lobes of a liver. They include Riccia, Marchantia, Pellia, Porella.
* Habitat: They usually grow in moist, shady habitats such as banks of streams, marshy ground, damp soil, bark of trees and deep in the woods.
Riccia fluitans and Riccia carpus natans are aquatic.
* Habit: The plant body is thalloid, Parenchymatous, Prostrate, dorsi ventrally differentiated and dichotomously branched. The dorsal surface is green and ventral surface is colourless and attached to soil with the help of unicellular rhizoids. Porella is a leafy member. It bears tiny leaf like structures in two rows on stem like structures.
The plants are gametophytes. They show vegetative and sexual reproduction.
Vegetative Reproduction: Fragmentation is common.
It occurs by gemma in Marchantia. These are produced in a specialised structure called Gemma cups. These are formed on the dorsal side along the mid rib.
Sexual Reproduction: Sex organs are multicellular and jacketed. Male and female sex organs are called Antheridium and Archegonium respectively. Antheridium produces biflagellated antherozoids. Archegonium produces one egg cell. Marchantia is dioecious.
Fertilisation is internal and Zoidogamous type. It requires water. Zygote for the first time produces embryo. Hence the plants are called Bryophytes.
Asexual Reproduction: It is shown by sporophyte. It is very simple in Riccia and represented by capsule only.
Habit: The plant body is called thallus. It grows prostrate and dorsi ventrally ifferentiated. The thallus is variously branched. They lack mid rib unlike in hepaticopsida. The body is attached to the soil with the help of unicellular rhizoids.
Vegetative reproduction: It occurs by the separation of decaying branches.
Sexual Reproduction: Male and female sex organs are called Antheridium and Archegonium respectively. They are multicellular, jacketed, stalked and embedded.
Fertilization is zooidogamous oogamy. The zygote produces sporophyte.
Asexual Reproduction: Sporophyte is differentiated into foot, intercalary meristematic zone and capsule. It is homosporous. Spore produces gametophyte.
Characteristic pseudoelaters are present in the capsule.
It is haplo diplontic.
Its members are called Mosses. These are the highly advanced bryophytes. They include Funaria (Cord Moss), Polytrichum (Haircap Moss), Sphagnum (Peat Moss or Bog Moss).
It is differentiated into foot, seta and capsule in others. Capsule consists spore mother cells. They undergo Meiosis and produce haploid spores. These are homosporous. Elaters are seen in Marchantia. They are hygroscopic and help in the liberation of spores. Spores germinate and produce gametophyte.
Gametophyte is dominant. Sporophyte is dependent. They live together. The life cycle is called haplodiplontic. Sporophyte is dependant.
The members are called Horn worts as the sporophyte grows like horn on the gametophytic thallus. They include Anthoceros, Notothylas.
Thallus of Antheros is popular for its symbiotic association with Nostoc that helps in N2 fixation.
Habitat: They grow in moist shady localities, bark of the trees, burnt areas and moist old walls.
Habit: The gametophyte has 2 stages 1) Juvenile, ephemeral, alga like Protonema 2) adult, erect, leafy, branched, perennial gametophore. It is fixed to the soil with multicellular rhizoids. Growth is due to apical, single, pyramid shaped cell.
Vegetative Reproduction: It occurs by secondary protonema, tubers and gemmae.
Sexual Reproduction: Sex organs are multicellular, jacketed and stalked. They are mixed with multicellular, green, paraphyses. It is monoecious & autoicous. Fertilization is zoidogamous oogamy. Zygote develops into well developed, complex, sporophyte.
Asexual Reproduction: Sporophyte is differentiated into foot, seta & capsule. It is semiparasitic. It is autotropic but grows on gametophore.
It is homosporous. It has elaborate mechanism to release the spores. It shows peculiar peristomial teeth. The spore produces protonema.
Life Cycle: The Mosses show haplo - diplontic life cycle. Sporophyte grows on the gametophore.
These are herbaceous, erect, leaf bearing, green, autotropic, diploid, sporophytic, homosporous or heterosporous, archegoniate, embryophytic, first vascular or tracheophytic, highly advanced, cryptogamic true land plants. These are also called
Botanical snakes or Reptiles of the Plant Kingdom.
The study of pteridophytes is called Pteridology. These are divided into 4 classes.
1) Psilopsida (Psilotum)
2) Lycopsida (Lycopodium (Club Moss), Selaginella (little club Moss or spike Moss)
3) Sphenopsida (Equisetum or Horse tail)
4) Pteropsida (Adiantum or walking fern, Ophioglossum or adders tongue fern, Dryopteris, Pteris.
Habitat: These are terrestrial. They live in moist shady places. Some live in water. e.g.
Azolla, Salvinia, Marsilea. Marsilea is terrestrial also. Lycopodium squarrosum selaginella oregano are xerophytic.
Habit: The plants are herbaceous. It is a sporophytec. It is divided into root stem and leaves.
Root system in adventitious: Stem is herbaceous, creeping or erect and branched.
The leaves are simple with single midrib. The leaves in ferns (Pteropsida) are called fronds which show ramenta, circinate venation and furcate or open dichotomous venation.
Anatomy: These are the first vascular plants. Xylem do not consists vessels except Selaginella and Equisetum. Phloem consists Sieve cells. Companion cells are absent.
Secondary growth is absent. The plants show characteristic steles.
1) Protostele : The pericycle encloses vascular bundle consisting xylem surrounded by phloem. e.g.: Lycopodium, Selaginella.
2) Siphonostele: The stele has medulla in the centre. e.g.: Equisetum
3) Solenostele: It is a siphonostele with scattered leaf gaps. e.g.: Rhizome of Marsilea.
4) Dictyostele: It is a dissected siphonostele with overlapping leaf gaps. e.g.: Pteris (Ferns)
5) Amphiphloic Siphonostele: It is a siphonostele with Xylem ring sandwiched between outer and inner rings of phloem. e.g.: Marsilea stem.
Asexual Reproduction: The plants may be homosporous (Lycopodium, Pteris) or heterosporous (Selaginella, Salvinia).
Sporangia are produced on sporophylls. (Microsporophylls and Megasporophylls in case of heterosporous forms)
Development of the sporangium may be eusporangiate (develops from many cells) or leptosporangiate (develops from a single cell) Spore mother cells undergo Meiosis and produce spores. Sporophylls form compact structures called strobilus (Selaginella) or cones (Equisetum). In ferns sporophyll bears sporangia (in groups called sori) on the abaxial or ventral surface protected by indusium. Pteris shows false indusium.
The spores germinate to produce gametophyte. In heterosporous forms microspores and megaspores produce male and female gametophytes respectively. The gametophyte in ferns is called prothallus.
Heterospory is first found in Selaginella.
Sexual Reproduction: The gametophyte is green, independent and short living. It shows sexual reproduction.
Sex organs are multicellular, jacketed, sessile or embedded. Male and female sex organs are called Antheridium and Archegonium respectively. Antheridium produces biflagellated antherozoids ( multiciliated in ferns). Archegonium produces egg cell. Fertilization is zooidogamous oogamy.
In Selaginella zygote develops into 13 celled embryo but later female gametophyte falls on the ground. This incomplete retention of the female gametophyte is a significant step. If it is completely retained a seed will be formed. Thus it is a precursor to seed habit (development of the embryo in female gametophyte).
Zygote develops into sporophyte.
It is called Diplohaplontic. Sporophyte and gametophyte live separately.
These are primitive, first, group of flowering plants. The term Gymnosperms was coined by Theophrastus in his book 'Enquiry into Plants'.
These are arborescent (tree like), evergreen, autotropic diploid, heterosporous, monoecious or dioecious, archegoniate, tracheophytic, naked flower bearing, naked seed bearing flowering plants. (Phanerogams)
Sequoia (giant red wood tree) is the oldest (3500 years) and one of the tallest tree (111 metres). Zamia is the smallest gymnosperm ginkgo and Cycas are considered as relics of the past or living fossils. Gymnosperm mostly exhibit xerophytic characters. The plant body is divided into (1) Root (2) Stem (3) Leaf
Roots: They have tap root system. The roots in Pinus shows mycorrhiza (associate with fungus). The roots of Cycas give shelter to Nostoc and Anabaena and form coralloid symbiotic roots.
Stem: It is erect, woody, unbranched (Cycas) or branched (Pinus, Cedrus)
Leaves: They are simple, sessile, petiolate, evergreen. They have single midrib and side veins are absent, (unipinnate compound leaves in Cycas). They are reduced to needles in Pinus and Cedrus or scales in Ephedra. The leaves of Gnetum show reticulate venation as in dicots and those of Cycas show circinate vernation as in Fern.
Anatomy: Vascular tissues are present. Plants show secondary growth. Xylem do not shows vessels (except Gnetum).
Phloem has sieve cells. Companion cells are absent, some plants show albuminous cells. Vascular bundles are conjoint, collateral and open. Stem with soft wood is called Monoxylic (e.g.: Cycas) and hard wood is called Pyenoxlic (Pinus). Leaves show sunken stomata and thick cuticle.
Reproduction: Flowers are achlamydous (naked) and unisexual. Plants may be monoecious (Pinus), dioecious (Cycas) stamens are called microsporophylls. Carpels are called megasporophylls and open (i.e., they do not form gynoecium). Plants are heterosporous. Microspores and megaspores are produced from their mother cells respectively by Meiosis. The ovules are naked, orthotropous.
Microsporophylls & megasporophylls form compact structures called male strobilus (cone) and female strobilus (cone) respectively. Male cone and female cone of gymnosperous are equivalent to male flower and female flower of angiosperms.
Microspores (Pollengrain) fall directly on the ovules. It is direct pollination. It occurs by wind.
Microspore forms male gametophyte. Megaspore forms female gametophyte. Fertilization is zooidogamous oogamy or oogamy. Male gametes reach the female gamete by pollen tube. So it is called siphonogamy.
Gametophytes are highly reduced. Female gametophyte is completely retained. Embryo develops inside the female gametophyte. So seeds are formed. These are not covered by fruit wall. Female gametophyte forms endosperm.
Life Cycle: It is called Diplo haplontic
These are highly advanced phanerogams. These are herbaceous or shrubby or arborescent or climbing, deciduous or evergreen, leaf bearing diploid, sporophytic, heterosporous, monoecious or dioecious, vascular, non-archegoniate, embryophytic, fruit bearing phanerogams spermatophytes with cosmopolitan distribution.
The plants are divided into 2 classes.
(1) Dicotyledons and (2) Monocotyledons
Monocotyledons are advanced over dicotyledons.
Habitat: They are aquatic or xerophytic or mesophytic. Thus they show more ariations.
Habit: They are herbaceous or woody, shrubby or arborescent. Some plants grow as creepers, climbers, lianes, straglers or epiphytes. Some grow as parasites or saprophytes.
The plant body is divided into (1) Root (2) Stem (3) Leaves (4) Flower
Root System: It is tap root system in dicots and adventitious in monocots. Some hydrophytes like Wolffia, Ceratophyllum.
Stem: It is herbaceous or woody, unbranched (Borassus, Phoenix) or branched. Plants like Taeniophyllum, Monotropa have no stem at all.
Leaves: These are sessile or petiolate, simple or compound. Some plants like Taenospora, Taeniophyllum, Rafflesia have no leaves at all.
Flowers: These are distinct either bisexual or unisexual. In some plants are aggregated to form inflorescence.
Vascular tissues are seen in the form of vascular bundles. Xylem has vessels (except in Drimys, Trochodendron). Sieve tube cells and companion cells are present. Some plants of dicots show secondary growth.
Reproduction: Plants are heterosporous. Gametophytes are highly reduced.
Archegonia are absent.
Flagellated bodies are absent.
Flowers have conspicuous perianth (Calyx and Corolla) and sex organs. Male sex organs are stamens and gynoecioum respectively. Stamens produce pollengrains which fall on the stigma. It is called pollination which may be due to wind, water and animals. Siphongamy is seen. Pollen tube carries male gametes into the embryo sac where egg cell is present. Double fertilization (Syngamy and triple fusion) occurs and seed is formed. Seeds are enclosed by fruit wall. Seeds have characteristic triploid endosperm formed as a result of triple fusion.
Life Cycle: It is diplohaplontic.
* They are primary producers of food cycles of all aquatic animals.
* Heterocyst containing Blue green algae like Anabaena, Nostoc, Aulosira are capable of fixing atmospheric nitrogen to the soil.
* Algae like Laminaria, Porphyra, Sargassum, Codium, Chondrus etc are used as food.
* Chlorella, Spirulina and Scenedesmus are used as and are the source of SCP (Single Cell Protein).
* Algin is a hydrocolloid (holds water). It is a polymer of carbohydrate. It is viscous, jell forming and non-toxic in nature. It is obtained from the members of Phaeophyceae. It is used as thickner or emulsifier. It is also used to make covering for synthetic seeds.
* Carageenan is a hydrocolloid obtained from the members of Rhodophyceae (Gigartima, Chondrus). It is used in making soaps, sauces, milk shakes. It is used as thickner and emulsifier.
* Kelps (members of Phaeophyceae) are the richest source of Iodine.
* Agar-agar is a non-nitrogenous, inert polysaccharide obtained from the members of red algae like Gelidium, Gracilaria and Gigartina etc.
* Kieselguhr or Diatomite: Diatoms are unicellular with Silica in their cell walls.
Fossilised diatomaceous earth is used in tooth pastes, paints, insulating material, sound proof material.
* Algae in Physiology: Chlorella, Scenedesmus are used in physiological experiments.
* Algae in Genetics: Acetabularia is used in genetics experiments.
* Algae in Space: Chlorella, Sprirulina are used as food supplements by space travellers.
* Sphagnum (Peat Moss) is dried is used as substitute for cotton.
* Sphagnum has antiseptic properties. So it is used in dressing the wounds.
* Mosses are the food for herbivores.
* Peat Moss is used as fuel.
* Dried Mosses are used as packing material.
* Mosses are important soil builders. Their dense mats prevent soil erosion due to rain falling.
* Water places are gradually replaced by Peat Mosses and provide an area for terrestrial plants to grow. Thus they play a major role in plant succession.
* Mosses along with lichens are the first to colonise rocks. They decompose rocks by their secretions. Peat matter rich in organic matter is added to the soil formed by rocks. It becomes the suitable matter for the growth of higher plants.
* Several ferns like Polypodium, Adiantum Nephrolepis are grown as ornamentals.
* The species of Selaginella are sold which arise curiosity as resurrection plants.
* Lycopodium species have medicinal value in Homeopathic and Allopathic medicines.
* Species of Cycas, Taxus, Thuja, Auracaria, Juniperus etc are grown as ornamentals.
* Resins of gymnosperms have widen application Amber is obtained from Pinites succinifera. Canada balsam is obtained from Abies balsamaea. The important source of turpentine and venetion turpentine are Pinus and Larix respectively.
* Oil obtained from juniperus virginiana (Cedar wood oil) is used in microscopic works.
* Essential oils are obtained from Tsuga, Picea, Abies and Cedrus spp. These are used in perfumery and soap industries.
* Cedrus - Railway sleepers, Bridges
Pinus - Furniture
Pseudotsuga - Veneer for Plywood
Juniperus - Pencils
Agathis australis - Largest timber producing tree