Standardized Common Name: Roman Chamomile

Other Common Names: Common Chamomile, English Chamomile, Garden Chamomile

Family: Asteraceae (Compositae)

Taxonomy: Chamaemelum includes six mostly Mediterranean species that are closely related to Anthemis, a much larger genus with a broader range. The basionym of C. nobile is Anthemis nobilis L., and several wild species commonly known as chamomiles are still placed within the genus Anthemis.

Description: Perennial herb. Stems numerous, prostrate or ascending, branching, (5–)10–30 cm high. Leaves alternate, sessile, 2–5 cm long, oblong, deeply 2–3-pinnatisect; lobes numerous, crowded, linear, mucronulate, pubescent. Heads few, terminal, with long pubescent peduncles, 1.2–3 cm in diameter; in wild material, ray florets 12–20 or rarely absent, disk florets numerous; in cultivated material, most or all florets ligulate. Involucre hemispherical, 4–9 mm in diameter; involucral bracts (phyllaries) 4–6 mm long, in 2–3 rows, oblong to obovate, blunt, with scarious transparent borders and green midrib, slightly hairy. Receptacle conical, solid, with receptacular bracts (paleae) subtending flowers; paleae slightly shorter than disk florets (to ca. 3 mm), sometimes curving around florets, with blunt apex, scarious, bearing minute hairs. Ray florets female; corollas white, contracted into a tube at the base; ligules strap-shaped to ovate-oblong, 7–10 mm long with 3 inconspicuous apical teeth, usually 4-veined (rarely 3–6-veined). Disk florets bisexual, small; corolla yellow, tubular below, somewhat dilated at base, upper part campanulate and five-lobed. Achenes without pappus, ca. 1 mm long, smooth, pale greenish brown, with persistent corolla base at apex; with 3 faint ribs, 1 adaxial and 2 lateral.

Parts in Commerce: Heads

Identification: Commercially cultivated C. nobile is always more or less doubled (with some disk florets converted to ray florets); “single chamomile” usually refers not to the wild type but to those plants which still have a significant number of ray florets, as opposed to “double chamomile” in which nearly all florets are ligulate. Aromatic compounds are said to be more concentrated in the disk florets, so the preference for doubled flowers must be aesthetically rather than pharmacologically motivated. Since similar-looking wild contaminants will generally have only one whorl of ray florets, cultivated C. nobile is easily identified. In addition to the unusual appearance of the heads, whereby most or all florets are ligulate and white or yellowish-white, its features include:

• 1.2–3 cm in diameter
• Receptacle conical in longitudinal section (not flat or hemispherical), solid, with 2–3 rows of involucral bracts (phyllaries)
• Receptacular bracts (paleae) chaffy, densely covering receptacle
• Odor characteristic, aromatic
• Taste aromatic, bitter

If material of wild C. nobile is to be identified, many more species are similar enough to represent possible contaminants; smaller features should then be observed, such as the following:

• Corolla tube of ray florets distended at base, narrowly tubular below, bell-shaped at the top
• Achenes <1 mm long, with three faint, widely spaced ribs (not with 4+ ribs or with heavy ribs), crowned with persistent corolla base
• Pappus absent
• Receptacular bracts green to transparent, not with dark brown edges and apices, nor densely woolly.

Adulterants: Cultivated C. nobile is easily distinguished from most potential adulterants. Doubled heads of Tanacetum parthenium (L.) Sch. Bip. (Feverfew) are a reported adulterant; these flowers can be distinguished by their flattened receptacle. Doubled heads of feverfew sometimes have bracts on the receptacles, but they are comparatively few in number, more acute, and less membranous than those of C. nobile. The achenes of the ray florets also have a pappus in the form of a small corona. Flowers of Achillea ptarmica are also reported as potential adulterants; these likewise lack a conical receptacle, and are less than 12 mm in diameter.

Wild C. nobile could be confused with several plants, including species of Matricaria and Anthemis (c.f. Matricaria chamomilla L.) whose common names include “chamomile,” emphasizing their close resemblance. Matricaria is distinguished by its hollow receptacle. Anthemis, while very similar to Chamaemelum, lacks the swollen, persistent corolla base; in several common species, the achenes are >1 mm long with more than 3 ribs, and may have a small corona. Species of Tripleurospermum, closely related to Matricaria, may be distinguished by the presence of orange resin sacs on the lobes of the disk corollas. Other species of Chamaemelum have similar capitula, but have not been found as contaminants in commerce; these differ mainly in the above-mentioned features of the receptacular bracts.

References:

Bremer K, Humphries CJ. Generic monograph of the Asteraceae – Anthemidae. Bull Nat Hist Mus London (Bot). 1993;23:71–177.

Moore DM, Tutin TG, Walters SM, eds. Compositae. In: Tutin TG, Heywood VH, Burges NA, et al., eds. Flora Europaea. Vol. 4. Cambridge: Cambridge University Press; 1976:103–410.

Wichtl M, ed. Herbal Drugs and Phytopharmaceuticals, 3^rd English ed. Stuttgart: medpharm Scientific Publishers and Boca Raton, FL: CRC Press; 2004:127–129.

Figure 18: a–b, Chamaemelum nobile head.