Seminar on osmunda,dryopteris, 2
- 3. osmundales
- 4. OSMUNDACEAE
- 6. OCCURENCE Widely distributed in temperate and tropical regions of world. Plants prefer cool and shaded habitats. In India occur in north and north- western Himalayas upto altitude of 3000m.
- 7. Common species THE GENUS IS REPRESENTED BY 12 SPECIES
- 10. External morphology:- Medium sized fern with short upright or semiprostrate rhizomatous stem, clothed with hard persistant bases of old leaves and numerous dark coloured fibrus roots. Body is divided into stem, roots and leaves. Stem is semiprostrate showing dichotomous branching. Roots develop endogenously and fix the plant to substratum . Leaves are arranged in close spiral phyllotaxy at the apex of stem.They are circinately coiled when young. Young leaves are covered with simple uniseriate hairs but mature leaves are ,however, glabourous. Venation is open dichotomous. Some species are dimorphic show fertile and sterile leaves. Fertile leaves appear before sterile one.They are non-green and bear only sporangia directly on the branches of rachis.
- 11. In the absence of lamina ,sporangia are called marginal. In some species dimorphism is shown only by pinnae.
- 12. Internal structure Rhizome T.S. reveals vascular bundles-horse shoe (xylem are of various shapes;dictyostele),leaf trace c-shaped,indurated fiber ring ,cortex , endodermis and pith. Leaf structure is divided into petiole and leaflet. Petiole T.S. consist of epidermis with hairs ,hypodermis and ground tissue VB is cresent or horse-shoe shaped;endodermis is not well defined;mucilage canals also present. Leaflet T.S. consist of 2 layered epidermis consist mesophyll cells in between them contain chloroplast and VB are concentric present in midrib. Root rise endogenously from rhizome; epidermis later replaced by outer layer cortex; vascular bundle is diarch.
- 13. reproduction Sporophytic plant body give rise to gametophytic prothallus . Spores are homosporous rise on sporangia having indefinite sori,marginal in position. Some pinnae are completely or partially fertile. Sporangium are stalked, short and a pyriform structure. Development is eusporangiate type. Spore is spherical and have a triradiate mark. Spore on germination give rise to prothallus which is a elongated, dorsiventral, green and a cordate or heart-shaped structure. Prothallus give rise to antheridia and archegonia which produce spermatozoid and egg respectively. On fertilization it form zygote which on germination form sporophytic plant body.
- 16. ORDER:-FILICALES Include 300 genera and 9000 species. Largest group of pteridophyte. Most of these ferns are terrestrial,some are epiphytes on trunks. Leaves are circinnately coiled when young . Sporangia are marginal or superficial grouped together in sori. Leptosporngiate type and homosporous. Some examples are Pteridium,Adiantum,Dryopteris,etc,.
- 20. OCCURRENCE and uses This genus include 250 species around world from which 39 are reported in India. Grow well in north,west and eastern Himalayas. Found mostly in temperate,tropical and sub-tropical regions. Common species are D.ramosa,D.blanfordii,D.chrysocoma, D.hirteps,D.pulvinefera etc,. D.milneana is applied to boils, ulcers and wounds.D.filixmass for tapeworm.
- 21. SPOROPHYTIC PLANT BODY !
- 22. EXTERNAL MORPHOLOGY Plant body is divided into root, rhizome and leaves. Root and rhizome are subterranean. RHIZOME- It is semi-erect,creeping,short and obliquely placed;sparingly branched or unbranched and densely covered with brown,soft,broad and fimbricated scales. It grows by means of apical bud. ROOT- Primary root is short lived and replaced by adventitious roots that rise endogeneously from rhizome; branched and posses root cap. Have thin,black and wiry structure that anchor rhizome to the substratum and also absorb nutrition.
- 23. LEAVES OR FRONDS- Attain a height of 15-50cm ;circinnately coiled when young and become pinnately compound later;older leaves are distinguished into petiole and lamina;it may be unipinatte or bipinnate;every pinna can bear sporangia except D.cochleata.
- 24. INTERNAL STRUCTURE RHIZOME- 1. The T.S. of rhizome reveals epidermis, hypodermis and ground tissue. 2. Epidermis is single layer of rectangular cells and cuticle is thick. 3. Hypodermis is made up of few sclerenchymatous cells which provide mechanical strength. 4. Ground tissue consist of stele and meristele, wholly parenchymatous structure also help in food storage. 5. Stele is dictiyostele composed of oval or circular meristele arranged in a ring.It appear as cylindrical meshwork of vascular strand. 6. Meristele consist of endodermis followed by pericycle then by phloem and xylem.
- 26. ROOT- 1. T.S. reveals epidermis ,cortex,endodermis,pericycle and stele. 2. Epidermis slouged off during downward movement of root and is repelaced by outer layer of cortex which is known as exodermis or rhizodermis or piliferous layer which also consist of root hairs. 3. Cortex is divided into paranchymatous and sclerenchymatous cortex.PARANCHYMATOUS CORTEX is present next to epidermis and consist of 5-7 layers of thin walled polygonal cells having intercellular spaces while SCLERENCHYMATOUS CORTEX forms central mechanical cylinder external to vascular region, cells are polygonal and devoid of cytoplasmic content. 4. Endodermis consist of barrel-shaped cells having starch and also consist casparian strips. 5. Pericycle is made up of single layer of thin walled cells. 6. Stele is diarch and dictyostele .Secondary growth is absent.
- 28. LEAF- 1. Its internal structure is divided separately for pinnule and petiole. 2. PINNULE-V.S. reveal 2 epidermal layers of paranchymatous cells and contain chloroplast,mesophyll enclosing intercellular spaces having glandular outgrowths which store water and vascular bundle is of concentric or bicollateral type. 3. PETIOLE-T.S. is semi-circular and have groove on one side .It is divided into epidermis, 3-7 layered hypodermis and ground tissue .Stele is dictyostelic.
- 30. REPRODUCTION It takes place by vegetative and sexual method . Vegetative by fragmentation and formation of adventitious buds. Sexual reproduction is through archegonium and antheridium (spores).
- 31. Sexual reproduction GERMINATION AND NEW SPOROPHTIC PLANT FORM FERTILIZATION AND ZYGOTE FORMATION ANTHERIDIUM AND ARCHEGONIUM SPORES PROTHALLUS
- 32. Structure and development of gametophyte Every sporophyll has the capacity of producing spore which on germination produces prothallus which produces antheridium and archegonium. Antheridium consist of wall and three tabular cells (2 ring cells and a cap cell) and produce a spermatozoid. Archegonium consist of 8 neck canal cells, a venter canal cell and a egg cell .
- 37. Distribution and uses Cosmopolitan. Present in India along Himalayan tracts. Hardy plant once grow won’t let other ferns to grow. Around the world it only not found in arctic zone and temperate South America. P.aquilinum used in tooth ache and mouth infection.
- 38. EXTERNAL MORPHOLOGY Plant body is sporophytic divided into root,rhizome and leaves. Rhizome is subterranean and 6-15cm in length,creeping and profusely branched.3 types of branching is present :- long shoots,intermediate shoots and short shoots. Young rhizome are dichotomously branched. Leaves are present on short and thick branches,tripinnately compound and having length 2-12 feet. Roots are adventitious and endogeneous in origin.
- 40. INTERNAL STRUCTURE Rhizome shows different steles at different stages of life i.e.,protostelic(6-8mm),siphonostelic(5-6 week old),solenostelic(2.5-3 months old),dictyostele(1.5-2mm and start branching) and medullary stage .Other structures are similar to Dryopteris . Root is diarch. Pinnule structure is similar to bifacial leaf -2 epidermis ,stomata on lower side ,mesophyll cells(palisade and spongy paranchyma and contain abundant chloroplast),vascular bundle is collateral or concentric surrounded by endodermis. Petiole consist of outer epidermis ,scelerenchymatous hypodermis and paranchymatous ground tissue.Vascular bundle is horse shoe shaped.
- 42. Reproducion and development Vegetative reproduction is takes place due to broken branches it give plant a gregarious habit . No sporophyll present only segments of lamina or pinnules bear sporangia,coenosorus wedge shaped initial give rise to receptacle which bear sporangia. Spores are tetrahedral and lack perispore. Further development of sporangium and gametophyte is almost similar to Dryopteris .
- 43. LIFE CYCLE
- 45. OCCURRENCE AND USES Family cyatheaceae include 5 genera i.e., Cyathea,Alsophila,Hemetelia,Lophosoria and Metaxya . Cyathea occur mostly in tropical rain forests and in India it is found in eastern Himalayas. Wood of this plant is extremely tough and durable ,therefore it is used in picket fences . From pulpy apical part of caudex starch is obtained. Ornamental .
- 46. EXTERNAL STRUCTURE Sporophytic plant body is divided into root, stem and leaves. Stem is short , stumpy ,dichotomously branched , thick, covered with hairs and also covered with adventitious roots in some species. Leaves are large upto 4m in height and repeatedly pinnate but also rarely simple.Young leavea are circinnately coiled. Roots are adventitious sometimes also present on trunk.
- 47. INTERNAL STRUCTURE o Mature stem is polycyclic dictyostelic and leaf gaps ,meristele,accessory vascular strand in pith (medullary bundles),narrow cortex and accessory cortical strand but absent in C.medullaris . o Stelar ontogeny is present in same stem at different nodes:- at base it is protostelic, at 8th node solenostelic only one leaf trace and they divide and finally form dictyostele. o Root and leaves structure are similar to other.
- 48. REPRODUCTION AND DEVELOPMENT Vegetative through fragmentation. Sexual through antheridium and archegonium. Receptacle is globose or elongated and is sufficiently raised and conta in indusium which is cup-like structure. It bears sporangia. Spore on germination form prothallus which further give rise to antheridia and archegonia which on fertilization (spermatozoid and egg) and germination give rise to sporophytic plant. Parthenogenesis also occur.
- 51. BIBLIOGRAPHY WWW.WIKIPEDIA.COM TEXTBOOK OF PTERIDIOPHYTE 2nd edition by P.C.VASHSHTA TEXTBOOK OF BOTANY by SINGH,PANDEY AND JAIN
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