disc mayweed
Family
AsteraceaeScientific Name
Matricaria matricarioides
Other Common Names:
pineappleweed
Synonyms (former Scientific Names):
Artemisia matricarioides
Lepidanthus suaveolens
Lepidotheca suaveolens
Matricaria matricarioides
Chamomilla suaveolens
Tanacetum suaveolens
Matricaria suaveolens
Santolina suaveolens
Habit
Pineapple weed has numerous hairless low-branching leafy stems. This species has a characteristic pineapple scent.
Leaves
Divided into several 1-2 mm wide segments the leaves of pineapple weed are 1-5 cm long and alternately arranged.
Identifying Characteristics
Cone shaped flower heads, numerous branches under 40 cm, and distinct pineapple scent. This plant is an alternate host for raspberry Scottish leaf curl virus.
Flower Seed Head
1 mm across the flower heads are present early spring to late fall. The terminal cone-shaped flower heads are composed of yellow disk flowers and 2-3 rows of greenish yellow floral bracts with papery edges.
Seed Fruit
An achene gives rise to a glossy, 5-sided, egg-shaped, light brown seed. Seeds usually measure 1.3 to 1.6 mm long and are no more than 0.7 mm wide with a few dark ridges.
Where Found
Prefers waste areas and roadsides, often found in the compacted soil of farmyards throughout Canada and the United States.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
pencil
Dominant Flower Color
Varies:
yellow,
green
Flower Symmetry
bilateral symmetry
Leaf Hairs
no hairs
Leaf Arrangement
alternate
Leaf Margin
entire
Leaf Structure
pinnate
Leaf Stalk
none
Stem Hairs
Varies:
has hairs,
no hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
taproot
Life Cycle
summer annual
Ochrea
not present
Plant Type
Herb