Chapter 13 Botany The Study of Plants Plant

Chapter 13 Botany The Study of Plants

Plant classification �Classification – based on the presence or absence of vascular tissue (veins). � 1. Nonvascular plants- Bryophyta – Ex. Mosses � 2. Vascular w/o seeds – Pterophyta – Ex: Ferns � 3. vascular plants w/seeds – 2 subgroups: a. nonflowering plants – gymnosperms � b. flowering plantsangiosperms �

Non-Vascular Plants Phylum Bryophyta – mosses �found on rocks, in shady areas, on logs near streams. (dominant vegetation in the tundra)

Life Cycle of a Moss �Leafy shoots contain either male or female structures. Produce gametes – called gametophyte. �Fertilized ovum grows into a stalk w/capsule on top. (now called a sporophyte) – result of joining of two gametes -> therefore diploid. �Top of male- antheridia – sac containing spiral shaped sperm. �Sporophyte begins as parasite on the gametophyte �Top of female- archegonia – contains ovum(egg cell) �When mature - cap comes off -> wind distributes spores. �Water and clusters of gametophytes are essential for fertilization. �Spore will begin to grow -> grows into a gametophyte.

Alternation of Generations – Ex: life cycle of moss.

Vascular plants w/o seeds Phylum Pterophyta – Ferns �Do not produce seeds, produce spores. �Grow in shaded, cooler areas, some in dry areas �Fern leaf – frond – grows in clumps from a single rhizome (produces new clumps asexually) �Sori- spore producing sporangia found on the underneath side of fronds.

Life Cycle of a Typical Fern �Spores are released – carried by the wind. �They germinate – form a heart shaped prothallus �Underside develops rhizoids(roots), archegonia(female parts), antheridia(male parts). �Sperm are released from the antheridia and swim to ovum. �Prothallus is gametophyte. �Zygote matures and grows into a sporophyte (completing the cycle).

Life Cycle of a Typical Fern

Vascular Plants with Seeds �two groups- gymnosperms, angiosperms �gymnosperms – non flowering plants that produce seeds not enclosed in an ovary when mature. Ex: pine �phylum coniferophyta – produce seeds in cones. � life cycle of pines – pollen cones and seed cones are involved. � pollen cones – found on tips – contains pollen and male gamete. � Seed cones – open green – pollen lands on scales- then scales close tight. When seeds are mature the cone opens �types of conifers �yews �cypress �pine �redwoods family

Phylum Anthophyta – flowering plants �called Angiosperms - over 400 different families, - 250, 000 species. �Ovary of plants – encloses seeds. �Mature ovary – fruit �Monocots – one cotyledon in a seed. �Dicots – two cotyledons in a seed. �Monocots �Parallel veins �Roots – fibrous �Stems- scattered veins Dicots netted veins roots – tap Stems – veins in a ring.

Plant Anatomy �Herbaceous plants – lack woody plant structures. �vegetative organs – leaves, roots, stems �reproductive organs – flowers, fruits, seeds �Tissues �meristematic tissues – found in buds, root tips and stems. (mitosis occurs often in this area). �Vascular tissue- xylem – long , thick walled cells – carry water from roots to rest of plant. (upward) � phloem – carries dissolved food (sugar- downward) except in spring when sap rises up from roots to leaves as the leaves are developing �

Leaves �leaf venation �parallel �netted �pinnate �palmate �types of leaves �simple �compound