Vegetative features Black and White Stock Photos & Images

. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 299 It is noteworthy that while certain vegetative features may in some cases be cited as family-characters, such features are not usually of much value from a taxonomic point of view.. Fio. 232. Davallia aculeata. (| nat. size.) While the typical tree ferns are practically all members of the Cyatheaceae, a few members of other families, e.g. Tudea harhara (Osmundaceae) and the monotypic Indian genus Brainea (Pol}-. Please note that these images are extracted from scanned page images that may have been digital Stock Photo

RMPG15N1–. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 299 It is noteworthy that while certain vegetative features may in some cases be cited as family-characters, such features are not usually of much value from a taxonomic point of view.. Fio. 232. Davallia aculeata. (| nat. size.) While the typical tree ferns are practically all members of the Cyatheaceae, a few members of other families, e.g. Tudea harhara (Osmundaceae) and the monotypic Indian genus Brainea (Pol}-. Please note that these images are extracted from scanned page images that may have been digital

RMRDBBN7–. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 299 It is noteworthy that while certain vegetative features may in some cases be cited as family-characters, such features are not usually of much value from a taxonomic point of view.. Fio. 232. Davallia aculeata. (| nat. size.) While the typical tree ferns are practically all members of the Cyatheaceae, a few members of other families, e.g. Tudea harhara (Osmundaceae) and the monotypic Indian genus Brainea (Pol}-. Please note that these images are extracted from scanned page images that may have been digital

. Fossil plants : for students of botany and geology . Paleobotany. 266 COKDAITEAB [CH. between seeds and vegetative organs, and while it is possible to state with confidence that many of the seeds represented by impressions described as species of Samaropsis and Cordaicarpus are midoubtedly Cordaitean, it is certain that not all seeds refer- able to these genera were borne by Cordaitalean plants. Cordaitean seeds are characterised by certain morphological features recaUiag those found in recent Cycads and in the seeds of Ginkgo as illustrated by species of Cardioca/rpus and some allied types. Stock Photo

RMPG0D1E–. Fossil plants : for students of botany and geology . Paleobotany. 266 COKDAITEAB [CH. between seeds and vegetative organs, and while it is possible to state with confidence that many of the seeds represented by impressions described as species of Samaropsis and Cordaicarpus are midoubtedly Cordaitean, it is certain that not all seeds refer- able to these genera were borne by Cordaitalean plants. Cordaitean seeds are characterised by certain morphological features recaUiag those found in recent Cycads and in the seeds of Ginkgo as illustrated by species of Cardioca/rpus and some allied types.

RMRDFDNY–. Fossil plants : for students of botany and geology . Paleobotany. 266 COKDAITEAB [CH. between seeds and vegetative organs, and while it is possible to state with confidence that many of the seeds represented by impressions described as species of Samaropsis and Cordaicarpus are midoubtedly Cordaitean, it is certain that not all seeds refer- able to these genera were borne by Cordaitalean plants. Cordaitean seeds are characterised by certain morphological features recaUiag those found in recent Cycads and in the seeds of Ginkgo as illustrated by species of Cardioca/rpus and some allied types.

. Lectures on the evolution of plants. Botany; Plants. 194 EVOLUTION OF PLANTS the New World, is the Bromeliaceae. These are char- acterized by modifications of the vegetative parts rather than by the flowers, which are rather simple in structure. Most of the order are epiphytes, and they form one of the most striking features of the tropical American flora. The best known of these are the so-called "Spanish. Fia. 47 (Monocotyledons, Scitamineae, OrohidacesB). — A, flower of Canna: the flower is strongly zygomorphio, with inferior ovary, o, and the stamens reduced to a single one; B, the Stock Photo

RMPG1XX4–. Lectures on the evolution of plants. Botany; Plants. 194 EVOLUTION OF PLANTS the New World, is the Bromeliaceae. These are char- acterized by modifications of the vegetative parts rather than by the flowers, which are rather simple in structure. Most of the order are epiphytes, and they form one of the most striking features of the tropical American flora. The best known of these are the so-called "Spanish. Fia. 47 (Monocotyledons, Scitamineae, OrohidacesB). — A, flower of Canna: the flower is strongly zygomorphio, with inferior ovary, o, and the stamens reduced to a single one; B, the

. Lectures on the evolution of plants. Botany; Plants. 194 EVOLUTION OF PLANTS the New World, is the BromeliaceBe. These are char- acterized by modifications of the vegetative parts rather than by the flowers, which are rather simple in structure. Most of the order are epiphytes, and they form one of the most striking features of the tropical American flora. The best known of these are the so-called "Spanish. FiQ. 47 (Monocotyledons, Scitaminete, OrchidaeeaB). — A, flower of Canna: the flower is strongly zygomorphic, with inferior ovary, o, and the stamens reduced to a single one; B, the Stock Photo

RMRDTPPJ–. Lectures on the evolution of plants. Botany; Plants. 194 EVOLUTION OF PLANTS the New World, is the BromeliaceBe. These are char- acterized by modifications of the vegetative parts rather than by the flowers, which are rather simple in structure. Most of the order are epiphytes, and they form one of the most striking features of the tropical American flora. The best known of these are the so-called "Spanish. FiQ. 47 (Monocotyledons, Scitaminete, OrchidaeeaB). — A, flower of Canna: the flower is strongly zygomorphic, with inferior ovary, o, and the stamens reduced to a single one; B, the

. Botany for agricultural students . Botany. 306 THALLOPHYTES vitally related that the colony of Volvox may be regarded as a multicellular individual rather than a colony. Re'production presents some interesting features. At first all cells of the colony are alike, but later considerable differentiation among cells occurs. Some cells of the colony enlarge and pass. Fig. 261. — Volvox. In the colony {Volvox aureus) the smaller cells bear- ing two cilia are the vegetative cells, the enlarged cells (a) contain sperms, and the enlarged cells (o), varying in size and stages of development, are eggs Stock Photo

RMPG4BD6–. Botany for agricultural students . Botany. 306 THALLOPHYTES vitally related that the colony of Volvox may be regarded as a multicellular individual rather than a colony. Re'production presents some interesting features. At first all cells of the colony are alike, but later considerable differentiation among cells occurs. Some cells of the colony enlarge and pass. Fig. 261. — Volvox. In the colony {Volvox aureus) the smaller cells bear- ing two cilia are the vegetative cells, the enlarged cells (a) contain sperms, and the enlarged cells (o), varying in size and stages of development, are eggs

RMRDG47M–. Lectures on the evolution of plants. Botany; Plants. 194 EVOLUTION OF PLANTS the New World, is the Bromeliaceae. These are char- acterized by modifications of the vegetative parts rather than by the flowers, which are rather simple in structure. Most of the order are epiphytes, and they form one of the most striking features of the tropical American flora. The best known of these are the so-called "Spanish. Fia. 47 (Monocotyledons, Scitamineae, OrohidacesB). — A, flower of Canna: the flower is strongly zygomorphio, with inferior ovary, o, and the stamens reduced to a single one; B, the

. Fossil plants : for students of botany and geology . Paleobotany. Fio. 190. Lepidodendron stem with Lepidostrohi. (After Hooker.) A. Side-view showing leaf-cushions on the left-hand side and the KnoiYia condition on the right. B. View of transverse section ; s, sections of Lepidostrohi. The fact that Lepidostrohi usually occur as isolated speci- mens renders it impossible in most cases to refer them to particular species of Lepidodendron. Neither external features nor anatomical characters afford satisfactory criteria by which to correlate vegetative and fertile shoots; in some measure this Stock Photo

RMPG161D–. Fossil plants : for students of botany and geology . Paleobotany. Fio. 190. Lepidodendron stem with Lepidostrohi. (After Hooker.) A. Side-view showing leaf-cushions on the left-hand side and the KnoiYia condition on the right. B. View of transverse section ; s, sections of Lepidostrohi. The fact that Lepidostrohi usually occur as isolated speci- mens renders it impossible in most cases to refer them to particular species of Lepidodendron. Neither external features nor anatomical characters afford satisfactory criteria by which to correlate vegetative and fertile shoots; in some measure this

. Botany of the living plant. Botany. 192 BOTANY OF THE LIVING PLANT is no self-nutritive function necessary in tlic parasite, and the leaves which normally carry it on are not required. Such reduction of the vegetative system is usual in complete parasites. But this reduction does not apply to the floral region. The flowers of the Dodder, which are produced in dense heads, arise each in the axil of a bract, and struc- turally they show the characteristic features of the Convolvulaceae. From these facts the conclusion seems justified that Dodder is a type related to Convolvulus, and that the t Stock Photo

RMRDY8FE–. Botany of the living plant. Botany. 192 BOTANY OF THE LIVING PLANT is no self-nutritive function necessary in tlic parasite, and the leaves which normally carry it on are not required. Such reduction of the vegetative system is usual in complete parasites. But this reduction does not apply to the floral region. The flowers of the Dodder, which are produced in dense heads, arise each in the axil of a bract, and struc- turally they show the characteristic features of the Convolvulaceae. From these facts the conclusion seems justified that Dodder is a type related to Convolvulus, and that the t

. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. SPORE-PRODUCING MEMBERS 315 assist in conveyance of nourishment to the large mass of developing spores. Thus in the main features of form and dehiscence the sporangia of Rhopalostachya conform to the type of L. Selago, but are larger and more productive; while the sporophylls have a more elaborate form for purposes of protection. This goes along with the differentiation of the vegetative from the propagative regions, the steps of which have been traced above in the genus Lycopodium. The conclusion see Stock Photo

RMRDXG8Y–. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. SPORE-PRODUCING MEMBERS 315 assist in conveyance of nourishment to the large mass of developing spores. Thus in the main features of form and dehiscence the sporangia of Rhopalostachya conform to the type of L. Selago, but are larger and more productive; while the sporophylls have a more elaborate form for purposes of protection. This goes along with the differentiation of the vegetative from the propagative regions, the steps of which have been traced above in the genus Lycopodium. The conclusion see

. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 3ib SPORES OF SELAGINELLA These features are readily observed in longitudinal sections through the cones, which also show the presence of a small outgrowth (the ligule, Fig. i8i, /.) from the upper surface of each sporophyll, between its upturned tip and the sporangium. Such ligules, though most conspicuous on the sporophylls, oc- cur also on all the vegetative 1 e a ^f e s , but their function is altogether obscure. A ligule is not met with in the genus Lycopo- diiiin, but ap- pears to ha'e been character- Stock Photo

RMRDWP66–. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 3ib SPORES OF SELAGINELLA These features are readily observed in longitudinal sections through the cones, which also show the presence of a small outgrowth (the ligule, Fig. i8i, /.) from the upper surface of each sporophyll, between its upturned tip and the sporangium. Such ligules, though most conspicuous on the sporophylls, oc- cur also on all the vegetative 1 e a ^f e s , but their function is altogether obscure. A ligule is not met with in the genus Lycopo- diiiin, but ap- pears to ha'e been character-

. A textbook of botany for colleges and universities ... Botany. THALLOPIIYTES 25 cell of the Volvocalcs, even to the " eye spot" and contractile vacuoles. The spores escape through an opening in the wall of the mother cell, swim about, come to rest, settle upon some support, ciliate end foremost, develop a holdfast, begin cell division, and new filaments are started (fig- 57)- This differentiation between zoospores and ordinary vegetative cells, and the behavior of the zoospores in escaping individually from the mother cell > and starting inde- pendent individu- als, are features Stock Photo

RMRDXTFR–. A textbook of botany for colleges and universities ... Botany. THALLOPIIYTES 25 cell of the Volvocalcs, even to the " eye spot" and contractile vacuoles. The spores escape through an opening in the wall of the mother cell, swim about, come to rest, settle upon some support, ciliate end foremost, develop a holdfast, begin cell division, and new filaments are started (fig- 57)- This differentiation between zoospores and ordinary vegetative cells, and the behavior of the zoospores in escaping individually from the mother cell > and starting inde- pendent individu- als, are features

RMRDD88D–. Botany for agricultural students . Botany. 306 THALLOPHYTES vitally related that the colony of Volvox may be regarded as a multicellular individual rather than a colony. Re'production presents some interesting features. At first all cells of the colony are alike, but later considerable differentiation among cells occurs. Some cells of the colony enlarge and pass. Fig. 261. — Volvox. In the colony {Volvox aureus) the smaller cells bear- ing two cilia are the vegetative cells, the enlarged cells (a) contain sperms, and the enlarged cells (o), varying in size and stages of development, are eggs

RMRDBBY3–. Fossil plants : for students of botany and geology . Paleobotany. Fio. 190. Lepidodendron stem with Lepidostrohi. (After Hooker.) A. Side-view showing leaf-cushions on the left-hand side and the KnoiYia condition on the right. B. View of transverse section ; s, sections of Lepidostrohi. The fact that Lepidostrohi usually occur as isolated speci- mens renders it impossible in most cases to refer them to particular species of Lepidodendron. Neither external features nor anatomical characters afford satisfactory criteria by which to correlate vegetative and fertile shoots; in some measure this

. Botany, with agricultural applications. Botany. 306 THALLOPHYTES vitally related that the colony of Volvox may be regarded as a multicellular individual rather than a colony. Reproduction presents some interesting features. At first all cells of the colony are alike, but later considerable differentiation among cells occurs. Some cells of the colony enlarge and pass. Fig. 261. — Yolvox. In the colony (Volvox aureus) the smaller cells bear- ing two cilia are the vegetative cells, the enlarged cells (a) contain sperms, and the enlarged cells (o), varying in size and stages of development, are Stock Photo

RMRDWDHB–. Botany, with agricultural applications. Botany. 306 THALLOPHYTES vitally related that the colony of Volvox may be regarded as a multicellular individual rather than a colony. Reproduction presents some interesting features. At first all cells of the colony are alike, but later considerable differentiation among cells occurs. Some cells of the colony enlarge and pass. Fig. 261. — Yolvox. In the colony (Volvox aureus) the smaller cells bear- ing two cilia are the vegetative cells, the enlarged cells (a) contain sperms, and the enlarged cells (o), varying in size and stages of development, are

Vegetative features Black & White Stock Photos

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