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Life Cycles & Weed Classification Flashcards
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Life Cycles & Weed Classification Flashcards

Created by
@IllustriousHoneysuckle

Questions and Answers

What are the five methods that help us classify weeds?

  • Life cycle (ontogeny) (correct)
  • Physiology (correct)
  • Habitat (correct)
  • Origin (correct)
  • Taxonomy/morphology (correct)

    • What are two weed origins?

    Native/indigenous/apophytes and Alien/exotic/neophytes

    Name three examples of alien invasive species in Canada.

    Giant hogweed, Japanese knotweed, Leafy spurge

    What are six examples of habitat classification?

    <p>Agrestal, Ruderals, Grassland weeds, Aquatic weeds, Forest weeds, Environmental weeds</p> Signup and view all the answers

    What is taxonomy in weed classification?

    <p>The naming of species based on morphological characters, especially reproductive structures.</p> Signup and view all the answers

    Plants with similar traits are NOT grouped together.

    <p>False</p> Signup and view all the answers

    Many weeds are members of the _________ and _________ family.

    <p>Poaceae (grass), Asteraceae (composite)</p> Signup and view all the answers

    What are Dicots?

    <p>Seedlings that produce two cotyledons, for example: broadleaf plants.</p> Signup and view all the answers

    What are Monocots?

    <p>Seedlings that have one cotyledon, for example: grasses and sedges.</p> Signup and view all the answers

    What are the three life cycles (life history) in weeds?

    <p>Annuals, Biennials, Perennials</p> Signup and view all the answers

    What is the life cycle of an annual weed?

    <p>Completes its life cycle from seed to seed in less than one year.</p> Signup and view all the answers

    What are the characteristics of an annual weed?

    <p>Small herbs with shallow roots and a weak stem.</p> Signup and view all the answers

    Do annuals produce an abundance of seeds?

    <p>True</p> Signup and view all the answers

    What is the mode of propagation in annual weeds?

    <p>Mode of propagation is commonly through seeds.</p> Signup and view all the answers

    What are the two types of annual weeds?

    <p>Summer annuals and Winter annuals.</p> Signup and view all the answers

    When do summer annuals germinate, grow, produce seeds and die?

    <p>Summer annuals germinate in spring, grow in summer, produce seeds by fall, and die before winter.</p> Signup and view all the answers

    Name two examples of annual weeds.

    <p>Wild oat and Lambsquarters.</p> Signup and view all the answers

    When do winter annuals germinate, grow, produce seeds, and die?

    <p>Winter annuals germinate in fall, grow and produce seeds in spring, and die in summer.</p> Signup and view all the answers

    What is a facultative winter annual?

    <p>Facultative winter annuals can behave as both an early spring germinating summer annual and as a winter annual.</p> Signup and view all the answers

    What is an obligate winter annual?

    <p>Obligate winter annuals MUST germinate in the fall.</p> Signup and view all the answers

    All other winter annual weeds are ____________ winter __________.

    <p>facultative, annuals</p> Signup and view all the answers

    What are examples of facultative winter annuals? Name five.

    <p>Stinkweed, shepherd's purse, flixweed, narrow-leaved hawksbeard, chickweed.</p> Signup and view all the answers

    How long do biennials live?

    <p>Live longer than one year but less than two.</p> Signup and view all the answers

    How does a biennial plant develop in the first and second year?

    <p>In the first year, vegetative development occurs from seed into a rosette. In the second year, vegetative growth resumes followed by flowering and seed formation.</p> Signup and view all the answers

    Biennials do NOT have roots as storage organs after the first year.

    <p>False</p> Signup and view all the answers

    Biennials are usually a problem in arable agriculture.

    <p>False</p> Signup and view all the answers

    Common examples of biennials?

    <p>Common burdock, biennial wormwood, henbit, common groundsel.</p> Signup and view all the answers

    The plants live longer than _________ years and may __________ several times before __________.

    <p>two, reproduce, dying</p> Signup and view all the answers

    How do simple perennials reproduce?

    <p>By seed, examples include foxtail barley and dandelion.</p> Signup and view all the answers

    How do creeping perennials reproduce?

    <p>They reproduce by seed and a variety of vegetative organs.</p> Signup and view all the answers

    What are rhizomes?

    <p>Plants that have underground stems, example: Johnson grass.</p> Signup and view all the answers

    What are stolons?

    <p>Plants that have horizontal creeping stems above the ground, example: Bermuda grass.</p> Signup and view all the answers

    What are roots in the context of perennials?

    <p>Plants that have an enlarged root system with numerous buds, example: field bindweed.</p> Signup and view all the answers

    What are tubers?

    <p>Plants that have modified rhizomes adapted for the storage of food, example: Nutsedge.</p> Signup and view all the answers

    What are bulbs?

    <p>Plants that possess a modified stem with scales and reproduce mainly from bulbs and seeds, example: Allium sp.</p> Signup and view all the answers

    What are corms?

    <p>Plants that possess a modified shoot and fleshy stem and reproduce through corms and seeds, example: Timothy.</p> Signup and view all the answers

    Woody perennials are common on arable lands.

    <p>False</p> Signup and view all the answers

    How are life cycles not always distinct? Name three examples.

    <ol> <li>Facultative winter annuals are not always distinct. 2. Scentless chamomile is a biennial or a short-lived perennial. 3. Some biennials can survive more than two years (short-lived perennials).</li> </ol> Signup and view all the answers

    Physiology is based on what?

    <p>Is based on the photosynthesis mechanism (conversion of light energy into chemical energy).</p> Signup and view all the answers

    C4 plants do NOT have a more efficient photosynthetic process.

    <p>False</p> Signup and view all the answers

    C3 plants are more common.

    <p>True</p> Signup and view all the answers

    C4 plants do NOT thrive well in warm dry conditions.

    <p>False</p> Signup and view all the answers

    What are two weed management practices for alien invasive weeds?

    <ol> <li>Contain the spread of the weeds. 2. Biological weed control strategies are often used.</li> </ol> Signup and view all the answers

    What are two weed management practices for native species?

    <ol> <li>Containment is not a priority. 2. Weed control via herbicides/mechanical weeding.</li> </ol> Signup and view all the answers

    What are four examples of weed management practices for weed habitats?

    <p>Mowing, spraying, grazing, predation.</p> Signup and view all the answers

    How does herbicide selection differ between Monocots and Dicots?

    <p>The choice of herbicide will depend on whether the weed is a grass (monocot) or broadleaf (dicot).</p> Signup and view all the answers

    What is the main consideration with mowing for Monocots versus Dicots?

    <p>For monocots, the growing point is at or just below the soil surface; for dicots, there are multiple growing points at the end of every stem.</p> Signup and view all the answers

    What are two methods for controlling perennial weeds?

    <ol> <li>Fall is a great time to take care of perennial weeds. 2. Applying herbicide in fall takes advantage of the plant's nutrient storage behavior.</li> </ol> Signup and view all the answers

    What are two methods for C3 versus C4 control?

    <ol> <li>Under poorer growing conditions (drought), C4 weeds are more competitive with C3 crops. 2. Under changing climate conditions, C3 weeds can be more competitive.</li> </ol> Signup and view all the answers

    Study Notes

    Weed Classification Methods

    • Classification of weeds can be based on five methods: origin, habitat, taxonomy/morphology, life cycle, and physiology.

    Origin of Weeds

    • Weeds can be categorized as native (indigenous/apophytes) or alien (exotic/neophytes).
    • Examples of alien invasive species in Canada include giant hogweed, Japanese knotweed, and leafy spurge.

    Habitat Classification

    • Weeds can be classified based on their habitat:
      • Agrestal
      • Ruderals
      • Grassland weeds
      • Aquatic weeds
      • Forest weeds
      • Environmental weeds

    Taxonomy in Weed Classification

    • Taxonomy involves naming species based on morphological features, particularly reproductive structures.
    • Taxonomic classification groups plants with similar traits together.
    • Many weeds belong to the Poaceae (grass) and Asteraceae (composite) families.
    • Dicots are seedlings that produce two cotyledons, while monocots produce one.

    Life Cycles of Weeds

    • Weeds have three life cycle types: annuals, biennials, and perennials.
    • Annual weeds complete their life cycle from seed to seed in less than one year, characterized by shallow roots and weak stems, and produce a large number of seeds.
    • Types of annual weeds include summer annuals (germinate in spring, grow in summer, die before winter) and winter annuals (germinate in fall, grow in spring, die in summer).

    Biennial Weeds

    • Biennial weeds live longer than one year but less than two; they develop vegetatively in the first year and flower in the second year after a cold period.
    • They typically have roots as storage organs after the first year, and examples include common burdock, biennial wormwood, henbit, and common groundsel.

    Perennial Weeds

    • Perennials live longer than two years and can reproduce multiple times (polycarpic).
    • Simple perennials generally reproduce by seed (e.g., foxtail barley, dandelion), while creeping perennials reproduce by seed and vegetative organs.
    • Forms of vegetative reproduction include:
      • Rhizomes: Underground stems (example: Johnson Grass).
      • Stolons: Horizontal creeping stems above ground (example: Bermuda grass).
      • Roots: Enlarged root systems with buds (example: field bindweed).
      • Tubers: Modified rhizomes for food storage (example: Nutsedge).
      • Bulbs: Modified stems that reproduce mainly through bulbs (example: Allium species).
      • Corms: Modified shoots with fleshy stems (example: Timothy).
    • Woody perennials are not common in arable lands.

    Physiological Aspects of Weeds

    • Physiological classification is based on photosynthesis, especially the conversion of light energy into chemical energy.
    • C4 plants have a more efficient photosynthetic process than C3 plants, which are more common and include wild oat, lambsquarters, and dandelion.
    • C4 plants thrive better in warm, dry conditions (e.g., redroot pigweed, kochia, green foxtail).

    Weed Management Practices

    • Alien Invasive Weeds: Management involves containing the spread and employing biological control strategies.
    • Native Weeds: Focus on containment is less critical; strategies may involve herbicide use or mechanical weeding.
    • Habitat management practices include mowing, spraying, grazing, and predation.
    • Herbicide selection should depend on whether the weeds are monocots (grasses) or dicots (broadleaf plants).
    • Timing of weed control for perennials is best in the fall, as perennials relocate reserves to their roots during this time, enhancing herbicide efficacy.

    C3 vs. C4 Weed Control

    • Under poor growing conditions, C4 weeds are more competitive with C3 crops.
    • In changing climate conditions, C3 weeds can become more competitive with increasing CO2 levels.

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    Description

    Explore the various methods of classifying weeds, focusing on their origins, habitats, and life cycles. This quiz delves into alien invasive species in Canada and offers insights into the taxonomy and physiology of weeds.

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