Figure 1. Side view of flower of Jaltomata chihuahensis (all anthers dehisced), and flower bud (not yet open) on right. Photo by Thomas Mione, Mione 390 grown for study in the United States.
Figure 2. Flowers of Jaltomata chihuahensis, pistillate phase on left, hermaphroditic phase on right. Units are mm. Photo by Thomas Mione, Mione 390 grown for study in the United States.
Figure 3. Flower of Jaltomata chihuahensis (all five anthers dehisced). Photo by Thomas Mione, Mione 390 grown for study in the United States.
Figure 4. Back of flower of Jaltomata chihuahensis. Darker green is the calyx, lighter green is the corolla. Units are mm. Photo by Thomas Mione, Mione 390 grown for study in the United States.
Figure 5. Fruits (green when ripe) and funnel-shaped calyx of Jaltomata chihuahensis. Units are mm. Photo by Thomas Mione, Mione 390 grown for study in the United States.
Figure 6. Ripe fruits of Jaltomata chihuahensis fall free of the calyx. At left is the calyx/pedicel without a fruit because the fruit has fallen. Numbered units are cm. Photo by Thomas Mione, Mione 390 grown for study in the United States.

Figure 7. Flower, units on ruler are mm; photographed August 2003 by T. Mione, plant grown in Connecticut by T. Mione. Seeds generously provided by Robert Bye 14243 grown as Mione 421 for study in the United States.	Figure 8. Fruits, Branches, Leaves: Photo by Robert Bye 14243 in Mexico. Slide, scanned by T. M., generously provided by Robert Bye.

Figure 9. Fruits fall at maturity and calyx (the green upside-down "funnels" in photo) remains green. In side view, fruits are partially hidden by the calyx. Photo by T. Mione, T. Davis 1180 grown in Connecticut as Mione 390 grown for study in the United States.

JALTOMATA chihuahuensis Mione and R. Bye

Basionym: Saracha chihuahuensis Bitter, Repert. Spec. Nov. Regni Veg. 18: 108. 1922.
TYPE: Mexico. Chihuahua, Mpio. Casas Grandes: bei Colonia Garcia in der Sierra Madre, 2400 m, 18 July 1899. C.H.T. Townsend & C.M. Barber 91 (lectotype, MO; isotypes, K, NY, P; holotype designated by Bitter l.c. as "hb. Berol." presumed destroyed).  

Finger hairs short; not dense.  Leaves entire.  Inflorescence 2 - 4 flowered.  Peduncle 5 - 13 mm long.  Pedicel 11 - 20 mm long.  Flowering calyx 8 - 10.5 mm in diameter; lobe radius 3.7 - 5 mm; sinus radius 2 mm; finger hairs on abaxial face concentrated on the costa, about 10 per costa; the hairs not longer than 1 mm.  Corolla rotate, pale-green; 5-lobed; 19 - 24 mm in diameter during hermaphroditic state.  Stamens (not including expanded base) 3.9 - 4.0 mm long.  Filaments, slender part pubescent on basal 1/5th - 1/6th.  Filaments more or less parallel the style during the hermaphroditic state.  Anthers 1.7 - 2.3 mm long.  32.5 - 37.5 µm in diameter.  Style 3.7 - 5.6 mm long.  Stigma exerted beyond distal end of anthers by 0.6 - 1.6 mm; diameter 0.38 - 0.64 mm; round in overhead outline.  Infructescence 1 - 2 fruited; sometimes with a late developing flower or flower bud.  Fruiting peduncles drooping; fruiting pedicels pendent; always longer than the peduncle to which they are attached.  Fruiting calyx green; broadly infundibular, spreading over the fruit, covering it from above and from the side; no more than one fourth of the fruit shows from side-view.  Mature fruits green in accessions Bye & Linares 14243 and Bye et al. 18329 in greenhouse (this study) and the field (R. Bye, pers. comm.).  Mature fruits purple in the accession Davis 1180 in greenhouse (this study); if greenish when falls becomes purple/brown within a day or two after falling from the parent plant.  Fruits always falling free from parent plant without calyx/pedicel as soon as fruit is mature. 

Description based on living plants of Davis 1180 (TM 390), Bye & Linares 14243 (TM 421) and Bye et al. 18329 (TM 567).

     Diagnostic Features:  The filaments of all other species of section Jaltomata that I have grown for study markedly angle outwardly (inwardly on some accessions of J. repandidentata) during the first day of the hermaphroditic state while those of J. chihuahuensis only sometimes angle out, never more than 15 degrees.  Jaltomata chihuahuensis is similar to J. procumbens but the former has a 5-lobed corolla and calyx mostly covering the fruit from side view, while J. procumbens has 5 corolla lobes alternating with 5 corolla lobules, and fruits fully visible from side-view in Mexico.   

     Distribution and Habitat: Mexico, Chihuahua, pine duff on top of white volcanic rock outcrops in shade of pines, roadside.

     Uses: sweet to eat after falling from plant, sweeter than the purple form "rurusí" (Bye & Linares 14243; Bye et al. 18329).  Davis and Bye (1982, p. 232) seem to have been referring to this species when they wrote, "The term metárusi is applied to the prostrate form which has lighter colored fruits and which is said to produce an edible camote from the rootstock.  Metárusi is considered to be a class of rurusí.  It is known to occur in a few cultivated fields and is not as common as rurusí."

     Local Name: Tarahumara name is "metarsi" (Bye et al. 18329); "metárusi" (see Uses above, plant/specimen to which this name was applied not seen).  The fact that this taxon is recognized by a distinct name by the Tarahumara Indians is congruent with my decision to treat it as a distinct species (see Briggs and Walters, 1984, p. 255).

     Selected Specimens Examined. MEXICO. CHIHUAHUA: Rd. to La Bufa. 8.9 miles from La Bufa-Guachochi junction. T. Davis IV 1180 (CONN); mpio. Urique. al lado S de Barranca del Cobre, ca. 1 km al S de puente de Rio Urique. ca. km 61 de camino Creel-Guachoci, R. Bye & E. Linares 14243 (COLO, CONN)(TM 421).  

Ethnoecology: There are two races of J. chihuahuensis, one with purple fruits and the other with green fruits. Without mature fruits the two races appear to be morphologically indistinguishable. Based on greenhouse and garden studies of three accessions, we are certain that plants do not produce both types of fruits, nor do the mature green fruits become purple with age or exposure to sunlight. Information obtained by R.Bye from the Tarahumara during ethnoecological studies in Chihuahua, Mexico, agrees with these observations. Based on greenhouse studies, fruits of the purple race are typically green when they drop and then become purple within a few days.    

    The two races may occupy different niches. Preliminary observations by R. Bye are that the green-fruited race tends to occur among white volcanic rocks in soil with higher apparent organic matter. The purple-fruited race, however, is not found among white volcanic rocks nor in soil with high organic matter.  The rootstock ("camote") of the purple_fruited race is eaten by the Tarahumara (Davis & Bye, 1982: 232). Further study is needed to explore the possibility of niche specificity of the two  races. 

    Jaltomata procumbens (Cav.) J. L. Gentry, a widespread species that is common within the smaller range of J. chihuahuensis, is generally called "rurus," "rurus," "rurusi" or "turus" by the Tarahumara (e.g., Bye 9875 9889 COLO, Davis 1124 1127 MO; Brambila, 1976; Pennington, 1963). Jaltomata chihuahuensis, on the other hand, is often referred to as "metrusi" or "me'tresi" (which is a "jaltomate rastrero" or creeping jaltomate, Brambila, 1976); these names are probably derived from the Tarahumara verb 'me'trema' ('to be creeping'). Some Tarahumara believe "metrusi" to be a class of "rurus" (Bye, unpublished). Thus the Tarahumara recognize the distinction between J. procumbens and J. chihuahuensis.   

    In most Jaltomata species, at maturity fruits remain attached to the parent plant for at least a few days, and the accrescent calyx darkens when the fruit ripens. The color of the calyx (purple to brown) stands in contrast with the foliage and presumably serves, along with the brightly colored fruit, as a beacon to diurnal fruit consumers/dispersers. However, the fruits of J. chihuahuensis fall at maturity and the calyx remains green. Unlike most species of Jaltomata, which exhibit articulation at the base of the pedicel, articulation is at the attachment of the fruit; the calyx-pedicel unit remains attached to the plant for at least several days after the fruit drops. Human selection may result in a change from fruits falling free of the parent plant in wild species to fruits remaining attached to the parent plant at maturity (e.g., the nonshattering rachis of domesticated cereals, Heiser, 1990). The consumption of fruits by the indigenous people, perhaps subjecting the plants to human selection, has not had this effect on J. chihuahuensis.
Fruits falling free at maturity is among the features of the syndrome of saurochory (reptile dispersal) (Van der Pijl, 1969), and saurochory is thus a possibility for J. chihuahuensis, if not now then possibly prior to extensive utilization by humans. Alternatively, fruits falling free at maturity may indicate no adaptation for dispersal, and may merely have become fixed by genetic drift at some time when population size was small. In any case, fruits falling free at maturity suggests that this species is not regularly bird dispersed, although it is possible that birds feed on the fruits that have fallen to the ground. The Tarahumara Indians consume the fruits after they fall to the ground, and it is likely that seeds survive the human digestive tract and so become dispersed by humans (Davis & Bye, 1982; Davis, 1986). 

    Humans have selected for light color in diverse domesticates (e.g., white lupines, quinua, sheep and camels)(Heiser, personal communication; Zeuner, 1963). It is thus possible that green-fruited mutant(s) within J. chihuahuensis were selected by humans, giving rise to the green-fruited race. Evidence that may be considered as strengthening this scenario is that to humans green fruits are sweeter than purple fruits (Bye, unpublished).  Alternatively, humans may have had nothing to do with the establishment of the green-fruited race but may merely have begun to regularly consume the fruits.

    Phylogenetic Placement: Based on chloroplast DNA restriction sites there are two principal, sister phylogenetic groups within Jaltomata (Mione et al., 1994). The "Mesoamerican" group, having its center of diversity in Mexico, is widely distributed from southwestern USA to Bolivia. The "South American" group is distributed in Andean South America, the Greater Antilles, and the Galpagos Islands. Within the Mesoamerican clade the rarest and most morphologically distinct species, J. grandiflora, forms the most basal branch, and J. chihuahuensis forms the second to most basal branch (Mione et al., 1994). 

    Artificial Hybridizations: Crosses were made in a pollinator free greenhouse. Flowers used as pollen recipients were emasculated prior to anther dehiscence. No fruits were set from 18 crosses of J. procumbens with J. chihuahuensis (pollen source), nor from 12 of the reciprocal cross. Two accessions of J. chihuahuensis were used (Bye 14243 green fruits, Davis 1180 purple fruits). Six accessions of J. procumbens from Mexico were used (Davis 1189A 1191 1124, MO; Bye 9889 10033 10084, COLO), the latter four from Chihuahua. The following observations may be considered controls for the above crosses. Both J. chihuahuensis and J. procumbens abundantly self-set fruit in a pollinator free greenhouse. Within J. chihuahuensis an uncounted number of interaccession crosses have been successful (for study of the genetic control of fruit color), and within J. procumbens intraccession and interaccession crosses virtually always result in fruit set.

    Taxonomy: Jaltomata chihuahuensis has been considered to be a synonym of J. procumbens (Morton, 1938; Davis, 1986, discussed as the prostrate morph/form of J. procumbens; Nee, 1986). The decision to recognize this species and make the following new combination was based on morphological characters of both living plants (in the greenhouse and garden as well as in the field) and herbarium specimens, artificial hybridizations and chloroplast DNA (Mione et al., 1994). Chromosome counts of n = 12 were obtained for both J. chihuahuensis (Davis 1180) and J. procumbens (Bye 10033). Meiocytes were stained by crushing immature anthers with a fine dissecting needle in a drop of filtered acetic carmine.

    On pressed specimens of Jaltomata chihuahuensis the fruit is usually partially hidden by the calyx, because on living plants fruits are pendent and the calyx (an upside-down, five-lobed funnel as in photos above) hides the fruit from side view. On pressed specimens of J. procumbens, however, the calyx is more likely to lie flat against the sheet because on living plants the fruiting calyx is rotate. Based on hundreds of measurements made on plants grown during several years, these two species cannot be distinguished (due to overlapping ranges) with any one of the following characters: number of flowers per inflorescence, peduncle length, pedicel length, calyx diameter, corolla diameter, stamen length, anther length, style width at midlength, fruit length or width, nor seed length. 

    Acknowledgments. I thank Tilton Davis IV for the generous donation of his seed collection, maps and literature, the Tarahumara people for sharing their knowledge with R. Bye. Supported in part by an NSF grant to the University of Connecticut (T. M. and Gregory J. Anderson).   

	Figure 10, a lower left, b upper left, and c upper right. These three pictures are photos of the type specimen at P, photographed by Mione in April of 2004.

Figure 11. Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States. Note the internal primary phloem.

Section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States. Note the internal primary phloem.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States. Note the internal primary phloem.

Jaltomata chihuahensis. Cross section (by hand with a razor blade, stained with toluidine blue) and photography by Christopher L. Chan; Mione 390 grown for study in the United States.

Literature Cited

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D'Arcy, W. G., T. Mione & T. Davis IV. 1992. Jaltomata grandiflora (Solanaceae): a rare Mexican species. Novon 2: 190-192.

Davis, T. 1986. Jaltomata in the Tarahumara Indian region of northern Mexico. Pp. 405-411 in W. G. D'Arcy (editor), Solanaceae Biology and Systematics. Columbia University Press, New York.

_____ & R. A. Bye, Jr. 1982. Ethnobotany and progressive domestication of Jaltomata (Solanaceae) in Mexico and Central America. Econ. Bot. 36: 225-241.

Heiser, C. B. 1990. Seed to civilization: the story of food. Harvard Univ. Press, Cambridge. 

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Mione, T. 1992. Systematics and evolution of Jaltomata (Solanaceae). Ph.D. dissertation, University of Connecticut Storrs, CT.

_____, G. J. Anderson & M. Nee. 1993. Jaltomata I: circumscription, description and new combinations for five South American species. Brittonia 45: 138-145.

_____, & F. G. Coe. 1992. Two new combinations in Peruvian Jaltomata (Solanaceae). Novon 2: 383-384.

_____, R. G. Olmstead, R. K. Jansen & G. J. Anderson. 1994. Systematic implications of chloroplast DNA variation in Jaltomata and selected physaloid genera (Solanaceae). Amer. J. Bot. 81: 912-_918.

Morton, C. V. 1938. Notes on the genus Saracha. Proc. Biol. Soc. Wash. 51: 75-_77.

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Pennington, C. W. 1963. The Tarahumar of Mexico: Their environment and material culture. Univ. of Utah Press, Salt Lake City.

Van der Pijl, L. 1969. Principles of Dispersal of Higher Plants. Springer_Verlag, Berlin.

Zeuner, F. E. 1963. A history of domesticated animals. Harper & Row, New York.