Pineapple-weed


 * Latin Name**- Matricaria matricarioides
 * Kingdom-**Plantae
 * Psylum-** Anthophyta



__**Description-**__ This adventive annual plant is about 3-12" tall, branching frequently and having the appearance of a miniature bush. Fern-like leaves up to 2" long and ¾" across alternate along the hairless stems. These simple, double, or triple compound leaves are pinnately divided into linear lobes. The flowerhead of each stalk is about 1/3" across, and consists of numerous greenish yellow disk florets and no ray florets. Each disk floret has 4 tiny lobes at its apex. The top of the flowerhead is shaped like a dome or blunt cone. Both the foliage and flowerheads have a pineapple-like odor when they are bruised or crushed. Each disk floret is replaced by an oblong achene that is broader at the top than the bottom. The achenes are without awns or tufts of hairs. The root system consists of a branching taproot. This plant spreads by reseeding itself.


 * __Habitat-__** Pineapple Weed is a common plant in central and northern Illinois, but somewhat less common in the southern areas of the state. It is adventive from the Pacific Northwest. It is possible that this plant was originally brought to North American from NE Asia by Amerindians prior to the European settlement of the continent. Pineapple Weed has since spread to northern and western Europe, where it is not native. Habitats include stony slopes of pastures, barnyards, edges of driveways and sidewalks, gravelly areas along railroads and roads, and sunny waste areas that are rocky or gravelly. Disturbed areas are strongly preferred. It also prefers full sunlight mesic conditions, and gravelly or compacted soil. Competition from taller plants is not tolerated for very long.


 * __Associations and Uses-__** The flowers attract flower flies (Syrphidae) and are probably pollinated by them. Little is known about this plant's relationship to birds and herbivorous mammals in the NE or Midwest. Cattle reportedly make little use of it as a food source. It is possible that the seeds or flowerheads stick to the tires of motor vehicles and for this reason Pineapple weed often occurs along roadsides and driveways. Pineapple weed occurs in cereals and broad-leaved arable crops and has become a frequent weed of intensive vegetable crops. Pineappleweed is used medicinally, including as an effective worming treatment. The flowers smell of pineapple when crushed.

__**Features-**__ They reproduce only by seed. Leaves are very finely dissected, light green, smooth, hairless and they alternate. Flower heads are small, conic or egg-shaped and is yellowish-green. The whole plant, and especially the flower heads, when crushed has a distinct pineapple-like odour, like the common name. Flowers bloom from spring until autumn. Pineapple weed is distinguished by its small stature, its small flower heads without white ray florets, its smooth hairless stems below the flower heads, and its pineapple odour.


 * __Other Interesting Facts-__** This odd-looking little plant is closely related to the Mayweeds, Chamomiles, and other weedy daisies that have been introduced from abroad. They share the same kind of highly dissected foliage. However, Pineapple Weed lacks white ray florets in its flowerheads, unlike the others, and is less showy in appearance as a result. Another scientific name for this species is //Matricaria matricarioides//. The common name refers to the scent of the foliage and flowerheads.



__**Resources:**__ [] [] [] __ http://www.ppws.vt.edu/scott/weed_id/matmt.htm __ [] []