PLANT MORPHOLOGY – CONIFERS

Both evergreen and deciduous leaves exhibit characteristic broad blades in angiosperms, and narrow needle, scale-like, or awl-shaped leaves in the conifers. Figure 15.1 illustrates the different types of conifer leaves. Leaves may be borne singly on the shoot as in Picea spp. (spruce), in tufts or clusters as in Larix spp. (larch), or in fascicles (bundles) of 2-5 as in Pinus spp. (pines). The awl-shape and scale-like foliage of Juniperus spp. exhibits leaf dimorphism where a juvenile leaf form differs from the mature leaves of the same plant.

Types of conifer leaves with terms below: needles borne singly on shoot, scale-like, awl-shape — Figure 15.1 Types of conifer leaves.

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PLANT MORPHOLOGY – LEAVES

PLANT MORPHOLOGY – LEAVES Leaves are specialized structures for photosynthesis that provide plants with energy. Leaves arise at nodes just below an axillary bud on woody stems and are usually petiolate, that is composed of a blade and stalk-like petiole. Petioles may have stipules, two small leaf-like flaps that are attached at the base. In some cases, stipules on leaves and stems may become modified into spines, thorns, or prickles. Some leaves are sessile, that is, they lack petioles and have blades directly attached to the stem. When a bud is located in the axil of a single leaf and the stem, as shown in Figure 14.1 the leaf is classified as simple. Figure 14.1 Parts of a simple leaf However, when a bud is located in the axil of a structure with more than one leaf (leaflet) on attached to the axis (rachis), the leaf is classified as compound. As shown in Figure 14.2, even or odd numbers of leaflets may be pinnately compound that is, arranged along a central axis ...

Plant Classification

💬 INTRODUCTION TO PLANT CLASSIFICATION Classifying unknown plants as identical with or similar to plants within a particular taxonomic group involves observation and comparison. The ability to accurately distinguish and categorize the similarities and subtle differences among plant species relies on at least three interrelated skills: pattern recognition, description, and classification. Pattern recognition includes awareness of visual indicators such as shape, size, habit, etc. as well as other sensory input such as smell, touch, sound, etc. Much pattern recognition depends upon our ability to describe what is perceived. Frequently, people don’t remember those things they can’t describe in words. In contrast, those things, which are related to other more familiar things, are more easily recalled: for example, “it feels like velvet,” “it smells of lemons,” or “it appears to be bigger than a breadbox”. Descriptions allow people to identify and catalog those patterns. ...

CLASSIFY PLANTS BY LIFECYCLE

CLASSIFY PLANTS BY LIFE CYCLE A plant will go through a sequence of stages from seed germination to seed production as a mature plant. For some plants, this sequence, or life cycle may take a few weeks while others continue to grow and flower repeatedly over many years. Plant life cycles are classified as annual, biennial, or perennial. Annuals complete their life cycle of germination from seed, growing, flowering, fruiting and dying within a single season of growth. Biennials require two seasons to complete their life cycle. In the first season, foliage production and storage of food reserves takes place followed by flowering, seed production and death in the next. Perennials typically flower annually once established and may live for several to a great number of years. Types of Annuals While the annual life cycle is completed within a single season of growth, the term annual or bedding plant may also be used to describe any plant that is grown outdoors in the...

PLANT CLASSIFICATION

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