Lecture 3 - Weed Classification Flashcards
traits that affect where the plant can occur include:
life cycles
reproductive strategy
growth characters
what is classification based on
habitat
taxonomic/phylogenic
morphological
plant functional traits
life cycle/history
classifications of weeds - habitat
agrestals
ruderals
grassland weeds
aquatic weeds
forestry weeds
environmental weeds
agrestals
weeds of agricultural systems (cereal/oilseed crop, orchards, gardens, plantations)
how have many agrestals co-evolved with crop plants
early maturation and shattering
similarity in size and form
comparable seed size
examples of agrestals
wild oat and mustard
canada thistle
green foxtail
stinkweed
ruderals
weeds of waste/human disturbed sites (roadsides, industrial sites, railway lines, ditches)
examples of ruderals
scentless chamomile, common tansy, common mullein, white cockle, leafy spurge
grassland weeds
occurs in pastures and meadows, including range
examples of grassland weeds
diffuse knapweed, common yarrow
environmental weeds
suppress native vegetation and are of growing public concern
basically invasive species
example of environmental weeds
purple loosestrife, tall buttercup
classifications of weed habitats are not ______
discrete (can happen in more than 1 habitat)
what is the taxonomic classification of weeds based on
weed phylogeny (mono vs. dicots)
functional plant traits
why is classification of weeds based on traits and habitat not too successful
too many traits and habitats
how are life history differences relfected in a plants traits
germ and emergence time
growth habit and flowering time
reproductive strategy
distribution and occurence
annual weeds are well adapted to areas of _______ disturbance
high
biennial and perennial weeds are well adapted to areas of _______ disturbance
low
annual life cycle
complete life cycle within 12 months
germinate, grow, set seed, die
summer annual life cycle
from spring to fall
seeds dormant in winter
winter annual life cycle
from fall to spring/early summer
seeds dormant in warm summer soil
________ annuals make up a very high % of the weed population under conventional tillage
summer
t/f: winter annuals are facultative, meaning they can be summer or winter annuals
t
biennial life cycle
requires 2 growing seasons to complete life cycle
yr 1 = rosette
yr 2 = flowering, set seed, die
