Prenanthes alba Linnaeus

Remark The words or terms in red (actually dark orange) in the text are defined in a glossary.

sep_06_05c.gthmb can't be loaded. Prenanthes alba is a perennial, that is between 2 to 5 feet high; it has an erect central stem and often develops short side stems in the upper half; the stem is thick, light green to purple (usually the latter), glabrous, glaucous, and oozes a milky juice when broken. The plant has short and thickened fibrous taproots. It is native to North America. Its chromosome number (2n) is 32.

The plant belongs to the Asteraceae family.


In Greek, πρηνησ (prênês) means nodding and ανθοσ (anthos) means flower, the genus name alluding to the drooping flower heads.

In Latin, albus means white, the epithet referring then to the color of the ray florets of the species.

Common names

Some of the vernacular names of Prenanthes alba are Lion's-foot, White Rattlesnakeroot, Rattlesnake-root and White-lettuce. The French vernacular name is Prenanthe blanche.


Prenanthes alba has also been known as:


Prenanthes alba can be identified by its size, and its clusters of small nodding flower heads, its purplish stems, its relatively large, coarse, ovate or triangular leaves that are variable, and occasionally deeply 3-lobed.

It can be distinguished from the other Prenanthes in Québec by its primary bracts: each flower head has 8 primary bracts that are pale purple-green. In contrast, each flowerhead of Prenanthes altissima has 5 primary bracts that are light green. Furthermore, the ray florets of Prenanthes alba are more likely to be pale purple or lavender than those of Prenanthes altissima. As for the leaves of Prenanthes racemosa, they are oblanceolate to spatulate. draw.jpg can't be loaded.




Flower heads



Prenanthes alba habitats include rich mesic woodlands, sandy woodlands, bluffs, wooded slopes, rocky ravines and the base of cliffs in wooded areas, and woodland borders. It can be found in either oak (Quercus) or maple-basswood (Acer-Tilia) forests.


Prenanthes alba is found from New England to Iowa, and from Canada to Carolina. In Canada, it is found in Québec, Ontario, Manitoba and Saskatchewan. The map shows the Canadian provinces and USA states where the plant can be found. map_na.jpg can't be loaded.


The Chippewa Indians used dried, powdered root of Prenanthes alba added to food to produce postpartum milk flow. A decoction of the root, which is bitter is said to have been successfully used to cure the bite of the rattlesnake and also in dysentery. The Iroquois used a poultice against dog and rattlesnake bites, hence one of the common name Rattlesnake root. The Ojibwa used the sap especially in female diseases, as a diuretic.

Even though the foliage of Prenanthes alba has a bitter taste, it is sometimes browsed by White-Tailed Deers (Odocoileus virginianus).


The photos of the gallery were taken either with one of the following: Minolta DiMAGE 7, Canon PowerShot A530, Canon Xt Rebel, usually with the EF-S60mm f/2.8 Macro USM objective, Fujifilm A 610 and EPSON Perfection 1650 (scanner). The title in the window shows the date when the picture was taken, i.e. jan_30_06... would mean that the photo was taken on the 30th of January, the 06 is for the 6th picture taken that day. The month, day and picture number might be followed by a letter which I use to identify the system used to take the picture.

Click on the thumbnails to get larger view. The original photos are usually in TIFF format, the photos shown are generally in JPEG format, often of dimensions one half (surface one quarter) for loading time reduction.


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Flower heads

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Fruits, seeds

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