May 10, 2012

Crataegus spp. - Hawthorns


Crataegus (Hawthorns, Thorns, Haws) is a genus of low-growing trees and shrubs. One species is prized in Asia for its edible fruits (Bailey 1951:507), and they are also mentioned as food in early accounts in North America (Bailey 1951:507-509; Lopinot 2984:497; Phillips 1995; Yarnell 1963:229,239).

The genus Crataegus is taxonomically complicated. Species within this genus have been reclassified many times, and many have subsequently been rejected by taxonomists (Young and Young 1992:124). Three biological traits have made the classification of Crataegus species difficult. First, they are prone to hybridization, polyploidy, and apomixes. According to the Great Plains Flora Association (1986) fertile apomicts triploids are not uncommon. The process of polyploidy creates new species, and apomixes create microspecies that are often clumped into an aggregated taxon. The genus Crataegus is one of only a few genera of flowering plants that express the trait of apomixes. “Crataegiologists have named over 1,000 taxa, which more conservative taxonomists have reduced to a number of large complex species groups” (Great Plains Flora Association 1986: 370). The United States Department of Agriculture (USDA) reports 214 species of Crataegus growing in North America today (USDA, NRCS 2008), many of which are introduced or ornamentals. Young and Young   (1992:124) note that about 1100 specific names have been published, but claim this number has been reduced to between 100 and 200 species in North America. Due to the complexity of this genus and the brevity of this treatment, individual species will not be dealt with in detail here. However, morphological variation of seeds (nutlets) within the genus allows for a more detailed identification than simply at the generic level.

Figure 1. Seed of Crataegus mollis


All Crataegus seeds (nutlets, stones) are enclosed in a hard, thick endocarp. The endocarp is not as the coats of many seeds and had the potential of being preserved, therefore, in the archaeological record if charred. Inside the endocarp, the seed is also enclosed in a seed coat (Brinkman 1974). The seeds are often in a rounded-triangular shape; however, they may be almost spherical (Martin and Barkely 1973:165). Triangular seeds have two broad sides and a rounded back that often has course ridges and grooves. The seeds are often between 5 and 10 mm in length (Martin and Barkely 1973). A small hilum notch often occurs at one end of the angular edge. C. monogyna (European hawthorn), an introduced species, has seed measurments of 6.5 mm in length, 4.6 mm in width, and 4.6 mm in thickness (Montgomery 1977). C. pruinosa (frost haw) measures of 5.5 mm in length, 3.6 mm in width, and 3.2 mm in thickness (Montgomery 1977). An image of C. mollis is presented in Figure 1. Images of seeds from six different Crataegus species are presented in Figure 2.

Archaeological Distribution

While these seeds are not frequent in archaeobotanical assemblages in North America, their use as food has been proposed. Lopinot (1984:490-502) presents a list of “Potential Plant Food and Beverage Sources of the Carrier Mills Locale”, applying this list to his study area in southeastern Illinois between 4000 B.C. and 1000 A.D. However, the data in this report are from a number of published sources. In this report he includes C. crus-galli, C. engelmannii, C. mollis, C. pruinosa, C. punctata, and C. viridis (Lopinot 1984:497). He suggests all six taxa were potential food sources in his study area. Yarnell (1963:229,239) also talks about the potential of finding these seeds in archaeobotanical assemblages  in North America. Kelly (1932) describes the use of hawthorns in archaeological contexts associated with the Surprise Valley Paiute, California. Haw seeds were found at the Incinerator site on the western floodplain of the Great Miami River, Ohio (Wagner 1987:70). The site is a single component, Anderson Phase, Fort Ancient village (Wagner 1987:33). The seeds are interpreted as the remains of fruit-food.

Figure 2. Various Crataegus Seeds from (Young and Young 1992:125)

The Modern Plant and Its Distribution

Hawthorns grow across all of North America; however, the greatest concentration of species is in the eastern woodlands (Young and Young 1992:124). Branches of most species are covered in long thorns of varying length. The leaves are alternate and simple. The inflorescence is terminal on the branch and consists of a compound or simple cyme. The cymes may have few to many flowers, depending on the species (Great Plains Flora Association 1986). Flowers are five-petaled (Bailey 1951). Fruits are pomes (similar to an apple), and each one contains between one and five boney, one-seeded nutlets. The fruits are typically red or orange but can be yellow or nearly black (Bailey 1951). Fruits and seeds also vary in size and shape between species.
  Figure 3. C. pruinosa from USDA database                              


The fruits of most hawthorns have a pleasant flavor; however, the flavor varies from sweet to sour between plants, and many hawthorn fruits have an almost citrus taste. Historic accounts in North America discuss the processing of the fruits into jam. Phillips (1995) discusses the process and provides recipes. Due to the large size of the hard seed inside the fruit, defleshing it can be a labor intensive practice. Yarnell (1963:229,239) notes that hawthorns were eaten by Ojibwa, with the bark and thorns used for medicinal and technological purposes: “Thorns gathered in summer for sewing buckskin with sinew by Ojibwa. Products also used for food, medicine, and smoked to attract deer”. A wide variety of hawthorn plants are used today for ornamental purposes in modern North America (Young and Young 1992).


Bailey, Liberty. H.
     1951    Manual of Cultivated Plants, revised ed. Macmillan, New York.
Great Plains Flora Association
     1986    Flora of the Great Plains. University Press of Kansas, Lawrence, Kansas.
Lopinot, Neal H.
     1984    Archaeobotanical Formation Process and Late Middle Archaic Human-Plant  
          Interrelationships in the Midcontinental U.S.A. Unpublished Ph.D. Dissertation,  
          Department of Anthropology, Southern Illinois University at Carbondale, Carbondale,
Kelly, Isabel T.
     1932     Ethnography of the Surprise Valley Paiute. University of California Publications in  
          American Archaeology and Ethnology 31(3):67-210.
Martin, Alexander C., and William D. Barkely
     1973     Seed Identification Manual. University of California Press, Berkeley, California.
Montgomery, F. H.
     1977    Seeds and Fruits of Plants of Eastern Canada and Northeastern United States.
          University of Toronto Press, Buffalo.
     2008. The PLANTS Database,, 22 November 2008, National Plant
         Data Center, Baton Rouge, Louisiana.
Phillips, Jan
     1995    Wild Edibles of Missouri. The Missouri Department of Conservation, Jefferson City,
Wagner, Gail E.
     1987     Uses of Plants by the Fort Ancient Indians. Unpublished Dissertation for the
         Anthropology Department at Washington University, St. Louis.
Yarnell, Richard A.
     1963    Aboriginal Relationships Between Culture and Plant Life in the Upper Great Lakes
         Region. Dissertation prepared for the Department of Anthropology at the University of
         Michigan, Ann Arbor, Michigan.
Young, James A., and Cheryl G. Young
     1992     Seeds of Woody Plants in North America (Biosystematics, Floristic and Phylogeny
         Series), Vol. 4. Timber Press, Portland, Oregon.

Written by: Robert N. Spengler III