Composites with greenish flowers
What are they?
Though most members of the aster family have bright and cheerful flowers, a few have surprisingly dull or small, often greenish, flowers that are easily overlooked. Perhaps the best known of these is the common and widespread ragweed - famous as a major cause of hayfever in late summer and autumn.
Where are they found?
Most plants in this group tend to be plants of coastal habitats and disturbed ground. Look for them along roadsides and tracks in saltmarsh areas or in fallow fields.
Identification
Though the flowers may look similar, this is an easy group to identify as some are woody bushes while others are annual or perennial 'weeds'. Be sure to make a note of leaf shape and overall size and appearance of the plant.
Absinthe Wormwood Artemisia absinthium
Introduced from Europe and sometimes occurs as a garden escpae or relic of cultivation. Flowers July to September.
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Annual Wormwood Artemisia annua
An alien species, native to steppe grasslands of eastern Europe and central Asia. Uncommon but can form extensive colonies on waste ground and other dry, open areas. Salt-tolerant so may be found along drier parts of saltmarsh. Flowers August to October.
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White Sagebrush Artemisia ludoviciana
Introduced from western North America and occasionally found as a garden escape or relic of cultivation. Flowers August to October.
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Common Mugwort Artemisia vulgaris
(Common Wormwood) An alien species, introduced from Europe. Widespread, often forming large stands of rough vegetation in fields, roadsides and dusturbed ground. Often found on industrial sites and other well-trodden areas. Foliage strongly scented. Flowers July to October.
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like chrysanthemum leaves |
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Common Ragweed Ambrosia artemisiifolia
A very common to abundant annual 'weed' of disturbed ground and often carpeting the ground in the first year of abandonment of old fields. Flowers July to October.
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upright spikes |
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Great Ragweed Ambrosia trifida
Perhaps native in New Jersey but probably not native in Cape May. A scarce weed in our area which occasionally appears in disturbed soil but is short-lived and doesn't persist. Flowers July to October. The three-lobed leaves are quite distinctive but the plant is very variable and may be found growing as a singled-stemmed, low plant or as a tall, branching specimen.
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Rough Cocklebur Xanthium strumarium
A very common species of coastal habitats, including dunes, beaches and saltmarsh edge, as well as occasionally in disturbed fields and industrial sites inland. Easily identified by its very rough leaves and spiny seed pods, the latter hanging on the plant well into winter. Flowers May to September.
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Common Marsh-elder Iva frutescens
(Jesuit's-bark) This species is a common plant of saltmarsh edge and is particularly common around boatyards and marinas. Common Marsh-elder is a semi-woody sub-shrub, dying back almost to the ground overwinter, but retaining a woody base. It's fleshy leaves are an adaptation to a salty environment. Flowers August to late October.
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long, leafy bracts |
small teeth |
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