Cucurbita spp. and Lagenaria siceraria (Molina) Standley

Squash, gourd, and pumpkin; Bottle gourd
     Two groups of cucurbits, Lagenaria siceraria (bottle gourd) and Cucurbita spp. (i.e., squash, gourd, and pumpkin), are found in archaeobotanical assemblages from eastern prehistoric sites. Although dry rockshelters, caves, and other sites with good preservational conditions can yield uncharred cucurbit seed, rind, and peduncle, small fragments of charred cucurbit rind constitute our most common form of evidence.
       Rind coloration and topography can often distinguish between Cucurbitaspecies and bottle gourd on well preserved, relatively large uncarbonized remains. Bottle gourd epidermis tends to be brown with red undertones, whereas squash and gourd skin is usually a lighter brown or yellowish tan color. Warts, bumps, and ridges commonly occur on the surface of Cucurbita spp. rind. Although usually free of such growths, some varieties of Lagenaria siceraria  rind have warts (cf. Heiser 1979:78).
       Rind thickness has been used to differentiate these two taxa. Bottle gourd rind tends to be thicker than Cucurbita spp. rind. Past workers have used a rind thickness of 3.0 mm to distinguish these two groups. Specimens measuring 3.0 mm or greater were assigned to Lagenaria siceraria and those measuring less were deemed Cucurbita species. Considerable overlap in rind thickness between these groups and loss of epidermal and mesophyllic layers on archaeological rind makes this index a highly imprecise indicator of taxonomic group (Ford 1986). Its use is not recommended.
       Most of the cucurbit rind we deal with consists of small, carbonized, flotation-derived fragments. The size and shape of these fragments vary widely, but I have found pieces longer than about 2 cm to be uncommon. The texture of the upper and sometimes lower surface(s) of these specimens resembles burnt Styrofoam. Viewing these rind fragments in cross section is essential.  Together, cell structure and arrangement are the most reliable characters by which to identify cucurbit rind, whether charred or uncharred.
       Generally, it is not difficult to distinguish between types of rind specimens. Cucurbita spp. rind cells are isodiametric and occur in a regular configuration (Figure 1). Cells of Lagenaria siceraria rind are elongated and arranged in a comparatively irregular pattern (Figure 2). However, there are potential sources of confusion. Cellular patterning of cucurbit rind tends to vary in areas of rind located near the base (flower scar) and top (near the peduncle) of the fruit and around growths such as warts and ridges. Cucurbita spp. rind from these areas may look like bottle gourd rind.  Irregularities in rind composition occur in both groups. Thus, confidence of identification increases with specimen size.
       At high magnification, one can frequently see tiny white spheres in charred cucurbit rind. The circular depressions that once contained these structures are also apparent on many archaeological specimens. Many archaeobotanists follow an early designation of these structures as "cystoliths" or "calcium carbonate-containing cells" (Asch and Asch 1985:155). Subsequently, Asch and Asch Sidell (1992:241) determined that the structures were “non-reactive to acid, [and] hence cannot be calcium carbonate.” Although many sources define cystoliths in accordance to Asch and Asch (1985), elsewhere the structure are characterized more generally as “a mineral deposit usually of calcium carbonate” (Smith 1977:293). Bozarth (1987) has found distinctive spherical “phytoliths,” bodies composed of opaline silica in the epidermis of several species of Cucurbita. Considering the whitish, opaque appearance of some silica compounds (e.g., in grasses) after exposure to fire, it is feasible that the structures found in carbonized, archaeological specimens are phytoliths.
Archaeological Distribution
       Our earliest record of bottle gourd rind, dating to ca. 5300 B.C., comes from the Windover site in Florida (Doran et al. 1990). The Phillips Spring site in Missouri yielded rind from an occupation zone dating to ca. 2300 B.C. (King 1985). Early (ca. 5000 - 3000 B.C.) Cucurbita sp. rind has been recovered from several sites including: Koster and Napoleon Hollow in Illinois, the Haynes site in Tennessee, and Carlston Annis in Kentucky (Fritz 1994). Cucurbita spp. rind is a common constituent of plant remain assemblages from the central Mississippian drainage by 1000 B.C. (Fritz 1994; King 1985).

The Modern Plants and Their Distributions
       The Cucurbitaceae family is primarily tropical and sub-tropical in distribution and contains several taxa with fruits (pepos) that are economically valuable, including watermelon (Citrullus lanatus (Thunb.) Matsum & Nakai), cucumber and melon (Cucumis spp.). Wild species of Cucurbita are native to North and South America. Today, domesticated forms of squash, gourd, and pumpkin are grown in temperate and tropical areas world-wide. Lagenaria siceraria, indigenous to Africa, is currently cultivated throughout Africa, Central and South America, and Southeast Asia (Heiser 1989) for its hard, thick rind, which is used as a container.

Domesticatory Status and Taxonomic Issues
       Ethnohistorical and archaeological data indicate that at least two Cucurbita species occurred prehistorically in the East: C. pepo L. (Asch and Asch 1985; King 1985) and C. argyrosperma Huber ssp. argyrosperma (Fritz 1994). Genetic analyses indicate that at least one lineage of C. pepo was domesticated in the Eastern Woodlands (Decker-Walters et al. 1993). Species level identification of archaeological rind is regarded as difficult, if not impossible due to inter-specific overlap in thickness (see King 1985). Detailed studies of Cucurbita species rind morphology are lacking, however.

       The dried pepo of Lagenaria siceraria was and continues to be used as a container by people in many areas of the world, including prehistoric Eastern North America. Cucurbita sp. containers have also been recovered from Eastern prehistoric sites (Watson 1974).
       Rind, flesh, and seeds of Cucurbita species are edible and are nutritionally rich (King 1985).  Prehistoric paleofeces from Salts Cave, Kentucky contained both seed and rind fragments of this taxon (Yarnell 1974:114). Bottle gourd seeds have constituted foodstuff for African and Asian peoples both past and present. Seeds from modern cultivars are palatable and, as members of the Cucurbitaceae, are likely to be nutritionally on par with oil and protein rich Cucurbita spp. (Heiser 1989). Seeds of bottle gourd occur in human paleofeces recovered from at least one prehistoric site in the East (Yarnell 1969:44).

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Written by: Katherine M. Roberts