Shaggy Soldier is an introduced and naturalized erect annual forb, growing from 8 to 24 inches high on hairy much-branched stems. Stem hair is whitish and spread out from the stem.
The leaves are all stem leaves, opposite, stalked, lanceolate to broadly ovate in shape with 3 main nerves, with lateral veins branching from those. The margins are coarsely toothed, tips are pointed. Both surfaces and the margins usually have long white hair - not dense, although some plants may have denser hair than average. Leaves are up to 2-1/2 inches long and 1-3/4 inches wide. Upper stem leaves will be smaller and sometimes stalkless.
The inflorescence consists of several small flower heads in a branched cluster that is terminal and sometimes from the upper leaf axils.
The flowers have an involucre that is hemispheric to bell shaped, up to 1/2 inch wide when open, frequently narrower. There are two types of florets: An outer band of 4 to 8, but usually 5, ray florets whose corollas are usually white, but can be pinkish. These are pistillate and fertile. The broadly oval ray has a blunt tip with 2 notches that give the appearance of three large teeth. In the center of the head are 15 to 35 disc florets that have yellow corollas whose tubes are shorter than the 5-lobed throat. The throat lobes are triangular in shape and spread outward when the floret opens. Stamens have yellow anthers and the style branches. Disc florets are bisexual and fertile. There are 2 series of phyllaries around the outside of the flower head - green, broadly elliptic in shape with pointed tips. These tend to fall away early and if seeds have formed, frequently take the seed of the ray florets with them.
Seed: Both ray and disc florets when fertile produce a dry achene that is narrowly pyramidal in shape with attached short scales. The seed of the ray florets have 6 to 15 scales, those of the disc florets 14 to 20 (but sometimes none). Scales help with wind dispersion of the seed.
Habitat: Shaggy Soldier is an adventive plant, making its way into disturbed areas, pathway edges not tended frequently and even gardens. It has a fibrous root system and spreads by re-seeding. It needs at least partial sun, loamy soil and moist to mesic moisture conditions. As the alternate common name of "quick-weed" implies, it grows and flowers and sets seed very quickly.
Names: The genus Galinsoga is an honorary for 18th Century Spanish Doctor Mariana Martinez Galinsoga. Stern (Ref. #37a) states that his accomplishments match the smallness of the flowers. The species name, quadriradiata, comes from 'quad' meaning 'of fours' and the remainder of the word refers to the ray florets - thus 4 ray florets, which is somewhat of a misnomer as they can have 4 but 5 is more typical. The author names for the plant classification are: ‘Ruiz’ refers to Hipolito Ruiz Lopez, (1754-1816) Spanish botanist who researched the flora of Peru and Chile on expeditions sanctioned by Carlos III, the first lasting 10 years. ‘Pav.’ refers to Jose Antonio Pavon Jimenez, (1754-1840), Spanish botanist who researched the flora of Peru and Chile while on the first expedition sanctioned by Carlos II. He accompanied Ruiz. Over 150 new genera and 500 new species were named by the pair and those names still hold. The alternate common name of Peruvian Daisy comes from their discovery of this plant in Peru.
Comparisons: A cousin of this plant is the small quick-weed, Galinsoga parviflora. Other than being smaller, it has less hair and the phyllaries of the flower head are persistent rather than falling away. There are also differences in the seed and that is where a definite identification is made but it is less frequently found.
Above: Plants are 8 to 24 inches tall with opposite leaves.
Below: The small flower heads usually have 5 white ray florets and 15 to 35 yellow disc florets. Stems have spreading white hair.
Below: The upper leaf surface (1st photo) and the lower surface have long white hair as does the leaf margin.
Shaggy Soldier is an introduced species native to Mexico and South America. It is naturalized across most of the U.S. except the arid southwest and across all the lower Canadian Provinces. In Minnesota it is one of two species of Galinsoga found and is present in only 13 counties - all the metro area plus a few scattered others. The second species is G. parviflora, Smaller Quick-weed, and that is found in only 6 counties.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"