Jatropha (Euphorbiaceae) in Southwestern United States and Adjacent Northern Mexico

Transcription

1 Johnson Jatropha (Euphorbiaceae) in Southwestern United States and Adjacent Northern Mexico Matthew B. Johnson Jatropha 21 be used as patio plants and are compatible in cactus and succulent gardens. The various species make eye- catching container plants in or out of leaf. While some people object to plants which "look like a bunch of sticks" for much of the year, jatrophas can be appealing landscape subjects for those people who appreciate plants with unusual character. Used properly, they can enhance a landscape. The plants are low maintenance and are not appetizing to rabbits and other critters. Jatrophas are not likely to become widely used land- Desert Legume Program The University of Arizona 2120 East Allen Road Tucson, Arizona Jatropha includes perhaps 200 species of trees, shrubs, and herbs found in various tropical and subtropical habitats in North and South America, Africa, and India. Some species are monoecious while others are dioecious. Seeds of some species of Jatropha are used as powerful purgatives and a number of species are used in folk medicine and have other local uses. Some are grown as ornamental plants. The area covered by this study includes the portion of Texas west of the Pecos River, southern New Mexico, southern Arizona, and northern Mexico north of 28 latitude, including the state of Baja California, and portions of Sonora, Chihuahua, and Coahuila. No Jatropha are native to California. scape plants, but a few species can be found at some Arizona nurseries. Perhaps more nurseries will begin to propagate and market jatrophas as specialty landscape items. Most species are easily grown from scarified seeds and many will root from stem cuttings. Specific information on propagation and horticultural characteristics is described below. Jatropha cardiophylla (Torrey) Müller Limberbush, sangrengado, sangre de drago (Figure 1, Page 22) Shrubby plants, generally m (1-6.5 ft) tall, with several to 100 or more semi -succulent, erect or spreading, flexible stems arising from the roots. The stems are sparingly branched. The bark is smooth and dark reddish brown. The leaves are drought deciduous; the blades are 2-7 cm ( in) long and heart- shaped with irregularly toothed margins. Inconspicuous white flowers appear during the summer. The fruits are green and contain a single rounded seed, ripening from August to October. Within this region there are eight taxa of Jatropha: J. cardiophylla, J. cinerea, J. cordata, J. cuneata, J. dioica var. dioica, J. dioica var. graminea, J. macrorhiza var. Ridges, slopes, valleys, arroyos, and (southward) plains in Sonoran Desertscrub, thornscrub, occasional in tropical deciduous, and lower semidesert grassland m (200- septemfida, and J. malacophylla. J. cordata and J ft) elevation. Arizona in central and eastern Pima County, malacophylla are restricted to Mexico while the other taxa occur in both countries. The two varieties of J. dioica are confined to the Chihuahuan Desert portion of the region. J. macrorhiza occurs in grassland and woodland habitats above southern Pinal County and southeast Maricopa County, extending southward through much of lowland Sonora, Mexico. It is absent from the drier areas in northwest Sonora. the deserts. The other species are found in the Sonoran Limberbush is widespread and locally common but is inconspicuous when not in leaf. It frequently grows among other Desert region. plants as well as in the open, and seems equally at home In the southwestern United States, the shrubby species of Jatropha are often referred to as limberbush due to their flexible stems. The names sangrengado or sangre de drago (blood of the dragon) refer to the sap which exudes from cut stems and turns red on contact with air. The sap from minor cuts of young twigs is often clear, but will change color as it dries. The sap has been used as a dye. along sandy arroyos and on rocky hillsides. The plants produce leaves only during the summer months in response to rain. Limberbush will not leaf out before June in southern Arizona even if regularly watered although small leaves typi- cally appear a few weeks before the onset of the summer rainy season. The leaves turn bright yellow änd quickly fall in late September or October. Limberbush grows in areas which receive mm (8-20 in) of annual rainfall. Limberbush offer unique landscape possibilities for warm desert regions. The various species are strongly drought deciduous, and are leafless much of the year, displaying the attractive stems. When in leaf, the plants are distinctive with some having larger leaves than many other desert plants. The yellow or red autumn foliage provides a brief splash of color as the plants go dormant. Jatrophas are appropriate for desert landscapes where they can be combined with other desert shrubs and succulents as accent plants, keeping in mind the minimum cold tolerance of each species. They may Cut stems exude a watery sap which turns red and can stain clothing. Felger and Moser (1985) report that the roots are crushed and used as a red dye. The roots have also been used in tanning leather (Standley 1923). The stems contain small amounts of rubber. Limberbush is not specifically reported to be poisonous, however, other species of Jatropha are known to be toxic if eaten.

2 Desert Plants 22 Limberbush is easily grown from scarified seeds. Clipping a small section of the seed coat is sufficient to accomplish this. Approximately 80 percent germination was obtained from scarified seeds direct -sown in gallon containers with a 1998 long, and are kidney- or heart- shaped with entire or shallowly lobed margins. Flowers are bell- shaped and pink, appearing primarily in the summer and autumn. The 2-3 seeded capsules ripen in the late summer and autumn. daily air temperature range of C ( F). Germina- tion takes 5-8 days. Caution should be observed to prevent small ants from burrowing into the soil and destroying the seeds before they germinate. Plants were cm (12-16 in) tall at four months after germination. Limberbush may be grown from stem cuttings taken in the summer and treated with IBA. Cuttings are slow to establish and develop. Division is an effective method of propagation and the plants establish more rapidly than do those propagated from cuttings. Bare -rooted field -salvaged limberbush transplant with- out much difficulty although the plants should be quickly replanted to prevent them from drying out. Limberbush sustains stem damage at -5.5 to -6.5 C (20-22 F) but recovers rapidly the following summer. The plants are drought resistant but require regular irrigation during the summer for optimum growth. Limberbush will grow in full sun or partial shade. Red spider mites are an occasional problem on limberbush in the greenhouse. There are no other significant pest or disease problems and the plants are not browsed by rabbits or rodents. Limberbush makes an interesting accent plant in the ground or in a large container. Most abundant in deeper soils of valleys and plains in Sonoran Desertscrub and coastal thornscrub. Near sea level 925 m (2935 ft) elevation. Local in Arizona in Organ Pipe Cactus National Monument near the Mexican border and common and widespread in much of the Baja California peninsula and western Sonora to northwest Sinaloa. Ashy limberbush is common along both sides of the Gulf of California and sometimes grows abundantly on coastal dunes. The northern limits of its range are determined by winter freezing. Plants in Organ Pipe Cactus National Monument are generally less than 2 m (6.5 ft) tall and periodically suffer freeze damage. Ashy limberbush grows in areas which receive mm (6-14 in) of yearly rainfall. This species has been used as a mordant in dyeing, and has been used medicinally to treat warts and sore throats, and for hardening the gums (Standley 1923). The sap is used to treat hemorrhoids (Roberts 1989). Felger and Moser (1985) report that ashy limberbush is used by the Seri for a variety of purposes including dolls and headressess made from the stems, and arrow poison from the sap. Debarked roots of young plants are crushed and made into a tea to treat dysentery. The plants are readily propagated from seeds in the same manner as for Jatropha cardiophylla. Dormant stem cuttings taken in November failed to root, but Roberts (1989) reports that cut stems of this species are planted in parts of Baja California and root to form living fences. Ashy limberbush suffers severe stem damage below -4 C (25 F). In cultivation in Arizona it should be planted in a protected site. This species has similar horticultural requirements to J. cardiophylla but will remain in leaf for most of the year with sufficient moisture and warmth. Ashy limberbush is suitable as a specimen or container plant. Jatropha cordata (Ortega) Müller Tree limberbush, copalfo, torote papelio, miguelito (Figure 3, Page 23; Figure 8, Page 27) Large shrubs or small, rather upright trees 3-10 (12) m [10-33 Figure 1. Jatropha cardiophylla Jatropha cinerea (Ortega) Müller Ashy limberbush, (40) ft] tall with one or several well -developed succulent trunks. The bark is smooth and green, becoming straw colored and exfoliating in papery sheets. The leaves are drought deciduous; the blades are cm ( in) long, heart shaped or occasionally palmately 3- or 5- lobed; the margins are mostly entire or with small teeth bearing small, stalked glands. Pink or white flowers appear in the summer. Fruits are 2-3- seeded capsules ripening in August and September. Usually shrubs, 1-4 m (3-14 ft) tall with several semi- succu- Plains, valleys, slopes, and ridges in Sonoran Desertscrub, thornscrub, tropical deciduous forest and occasionally lower oak woodland. Near sea level m (3280 ft) elevation. lent stems. The bark is smooth and grayish. Leaves are Widespread in much of lowland Sonora except the arid north- drought deciduous; the blades are cm ( in) west and west central areas, ranging south to Jalisco. sangrengado, lomboy (Figure 2, Page 23; front cover)

3 Johnson Jatropha 23 Figure 2. Jatropha cinerea Figure 3. Jatropha cordata

4 Desert Plants 24 Tree limberbush is a distinctive plant which resembles some species of Bursera when not in leaf, but lacks the aromatic sap of the latter. The peeling bark is unique among jatrophas in the region. Walking on a hillside during the dry season among groves of leafless tree limberbush and Bursera as the wind rustles the peeling bark on the trunks and limbs is memorable experience. Tree limberbush grows in areas of Sonora which average mm (10-28 in) of yearly rain- fall. This species is most abundant in thornscrub and tropical deciduous forest. It enters the Sonoran Desert along the subtropical southeast margin where summer rainfall is highest and winters are often frost -free. Leaves appear with the summer rains and are strongly drought- deciduous in the autumn. The northern limit of the distribution of this species is directly related to freezing temperatures in winter. At its northern and elevational limits, plants have multiple trunks and frequently show evidence of past freezes. The wood is soft and is used by the Mayo andyaquí people in Sonora to carve ceremonial masks. Martin et al. (1998) indicate that sheets of bark of this species were once used to wrap cheese to keep it fresh. Seed propagation is as for the other species. Larger stems will root. Cut trunks used for fence posts have been observed to root and develop into new trees in the Alamos area in southern Sonora. Tree limberbush will sustain severe stem damage below -4 C (25 F). It would make an exceptional patio tree or landscape specimen for nearly frost -free locations, planted singly or in groups Jatropha cuneata is a characteristic plant of desert habitats along the Gulf of California where it is often one of the dominant species, growing with J. cinerea and species of Bursera. It is found on most islands in the Gulf. Shrubby limberbush grows in areas which receive mm (3-12 in) of yearly rainfall. This species grows in the hottest and driest habitats of any species of Jatropha in the region and the leaves are smaller than those of the other species. J. cuneata resembles Euphorbia misera and the two plants can be found growing together in parts of Baja California. The milky white sap of the latter readily distinguishes these species. The stems are used by the Seri for making baskets and headrings. Felger and Moser (1985) report that some Seri use the sap for arrow poison while others claim that it is not toxic. The bark is used for tanning, the stems yield a red dye, and the plant is used medicinally for a variety of purposes including the treatment of dysentery and sore throats (Standley 1923). This species is propagated from seeds in the same manner as the other species. Plants in 10 cm containers were cm ( in) tall at four months after germination. No information is available on vegetative propagation. The plants sustain severe stem damage below -3 C (26 F). Horticultural requirements for shrubby limberbush are similar to the previous species. It is suitable as a specimen plant for nearly frost -free landscapes and makes an attractive container plant when larger. It naturally develops a bonsai appearance in habitat and this can be encouraged in cultivation. Jatropha dioica Cerv. Leatherstem, rubber plant, Jatropha cuneata (Wiggins and Rollins) Shrubby limberbush, sangrengado, matacora (Figure 4; Figures 9 and 10, Page 28) Much -branched spreading shrubs, m ( ft) tall with semi -succulent stems. The bark is smooth or wrinkled and yellowish gray to brown. The leaves are produced in response to moisture throughout the year, falling with drought. The leaves are nearly sessile, cm ( in) long; those of mature stems are obovate or spatulate with entire margins while leaves of vigorously growing stems may occasionally be lobed. Small white flowers appear in the summer and are followed by single- seeded capsules which ripen in the late summer and autumn. sangrengado, sangre de drago Plants shrubby, with dozens of semi -succulent stems arising from a spreading underground root system. Old plants can develop patches over 3 m (10 ft) across with stems usually less than 1 m (3.3 ft) tall. The bark is smooth and dark reddish brown. In var. dioica, the leaves are commonly 1.53.O cm ( in) long by 6-10 mm wide and obovate to spatulate, while those of var. graminea are often cm (1-2 in) long by 1-4 mm wide and linear to narrowly oblanceolate. Leaf margins are commonly entire, but on vigorously growing stems they can be lobed. The leaves are clus- tered on numerous short spur branches. The flowers are small and white, and appear in the summer and autumn. The fruits are single- seeded capsules which ripen in the autumn. Jatropha dioica var. dioica: Plains, valleys, slopes, and ridges in Tamaulipan thornscrub and the lower margin of oak woodland (and southward to ) m ( (5000 +) ft) elevation. Ranging from the southern Edwards Plateau and the south Texas plains through the northeastern Mexican states to central Mexico.(Figure 5, page 25) Figure 4. Jatropha cuneata J. dioica var. graminea: Slopes, ridges, and plains in Chihuahuan Desertscrub and the lower margin of semidesert Ridges, slopes, plains, and arroyos in Sonoran Desertscrub. Near sea level - about 1000 m (3280 ft) elevation. Shrubby limberbush is found in Arizona from southeastern Yuma County to Organ Pipe Cactus National Monument and is widespread in Baja California and western Sonora to northwest Sinaloa. grassland (and southward to ) m ( (5500 +) ft) elevation. Leatherstem ranges from southwest Texas near the Rio Grande through parts of Chihuahua, Coahuila, San Luis Potosí, and Zacatecas, in Mexico.(Figure 6, Page 25; Figure 11, Page 28)

5 Johnson Jatropha 25 Jatropha macrorhiza (Bentham) (Figure i2, Page 28) Herbaceous stems to 0.5 m (1.6 ft) tall are produced from a large underground root during the summer months. The stem dies back completely in the fall. Large, palmately 5- or 7- lobed, blue -green leaf blades are up to 18 cm (7 in) long and have toothed margins. Showy pink flowers are produced in the summer. The fruits are 3- valved capsules which ripen in the summer and quickly release the rounded seeds. Figure 5. Jatropha dioica var. dioica Jatropha dioica will leaf out in mid -spring and will remain in leaf until frost if sufficient moisture is available. The leaves of var. dioica turn yellow in the autumn while those of var. graminea turn red, making the plants especially attractive. Grass -leaf leatherstem, var. graminea, grows in drier habitats in the Chihuahuan Desert in areas which receive mm (6-15 in) of rainfall. It often grows on rocky limestone ledges and slopes. It is replaced eastward by var. dioica which is found in the southwest portion of the Edwards Plateau and is widespread in Tamaulipan thornscrub to the east of the Chihuahuan Desert in areas which receive mm (15-25 in) of annual precipitation. The stems of leatherstem are reported to contain small amounts of rubber. Stems are used for hardening gums in Mexico. The seeds are widely reported to be eaten by white -wing doves and Powell (1988) reports that seeds are eaten by people in some parts of Texas. Since many jatrophas are known to be toxic, eating the seeds is not recommended. Stems of var. dioica are toxic if eaten by sheep or goats (Everitt and Drawe 1993). Seed propagation is the same as for the other species. Plants may be rooted from stem cuttings which are initially slow to develop, but are easily propagated by division. Leatherstem sustains stem damage at -5.5 to -6.5 C (20-22 F) but usually recovers the following summer. Plants are easily cultivated and respond to regular irrigation in warm weather. Leatherstem may be used as a unique accent plant in desert landscapes and combines well with cacti and other succulents. Figure 6. Jatropha dioica var. graminea Hills and slopes in semidesert grassland and oak woodland m ( ft) elevation. Found in Cochise, Santa Cruz, and southeast Pima Counties, Arizona, southwest New Mexico, and southwest Texas (one locality in Presidio County according to Powell, 1988), and in Chihuahua and northeast Sonora, Mexico. The northern variety is var. septemfida while var. macrorhiza occurs in central Mexico. Jatropha macrorhiza grows in areas which receive mm (12-20 in) of annual rainfall. Plants are locally common in the late summer in grassland and scrub areas in southeast Arizona. The clusters of pink flowers are attractive. The leaves and stems turn yellow and dry in the autumn months. Many references report that J. macrorhiza is toxic if eaten and Kearney and Peebles (1951) indicate that the roots are strongly purgative. This species is propagated from seeds which may be scarified. First -year seedlings produce two oblong cotyledons as their only leaves. The adult leaves are produced in subsequent years. The plants respond to regular irrigation when growing. This species would make an attractive addition to a rock garden or low -water use perennial flower garden. Jatropha malacophylla (Standley) Sycamore -leaf limberbush, sangrengado (Figure 7, Page 26) Shrubs or rarely small trees 2-5 m ( ft) tall, with semi - succulent stems arising from a short trunk. The bark of older sterns is smooth and gray, with soft, short pubescence on young twigs. The leaves are drought -deciduous; the blades are cm ( in) long, soft -fuzzy to the touch, and are palmately 5 -lobed with sparsely- toothed margins. White flowers appear with the new leaves in the summer. The fruits are 3- seeded capsules which ripen in the late summer and autumn. Slopes, valleys, canyons, and streamcourses in tropical deciduous forest m ( ft) elevation. Extending north of the 28th parallel only at lower elevations in the vicinity of Yécora, in eastern Sonora. It ranges southward in Mexico to Oaxaca. Sycamore -leaf limberbush is distinctive with its large, soft leaves, resembling those of species of sycamore (Platanus spp.). It is typically an understory plant in tropical deciduous forest and is sometimes found in moist situations along seasonal streams. The plants also occur in rocky habitats with cacti and drought -tolerant trees and shrubs. Plants gradually defoliate during the autumn and winter. Sycamore - leaf limberbush is found in areas of Sonora which receive

6 26 Desert Plants 1998 Figure 7. Jatropha malacophylla. Note that stem and leaf are different scale mm (20-28 in) of annual rainfall. This is the least xeromorphic species of Jatropha in the region. Germination requirements are as for the other species. Growth from seeds is rapid. Stem damage occurs below about -3 C (26 F). The interesting foliage provides a tropical effect and this plant could be used as an accent or container plant in a subtropical patio or minioasis setting. Acknowledgements The information presented in this study is based on observations of plants in habitat and of cultivated plants in Tucson, Arizona, on specimens at The University of Arizona herbarium, and on a review of the literature. Illustrations and photographs are by the author. I thank Richard Felger for his suggestions. Citations and References Benson L. and R. A. Darrow Trees and shrubs of the southwestern deserts, 3rd edition. The University of Arizona Press, Tucson. 417pp. Correll D. C. and M. C. Johnson Manual of the vascular plants of Texas. Texas Research Foundation, Renner, Texas. 1880pp. Everitt J. H. and D. L. Drawe Trees, shrubs, and cacti of south Texas. Texas Tech University Press, Lubbock. 213pp. Felger R. S. and M. B. Moser People of the desert and sea - ethnobotany of the Seri Indians. The University of Arizona Press, Tucson. 435pp. Felger R. S. and M. B. Johnson. In press. The trees of Sonora, Mexico. Oxford University Press.

7 Figure 11. Jatropha dioica var. graminea near Terlingua, Texas, October Figure 9. Jatropha cuneata north of Bahia Kino, Sonora, August Figure 12. Jatropha macrorhiza west of the Dragoon Mountains, Cochise County, Arizona, August Figure 10. Jatropha cuneata N 00

8 Johnson Jatropha 27 Johnson M. B Limberbush - Jatropha cardiophylla (Euphorbiaceae). The Plant Press :14(2):8-10. Kearney T. H. and R. H. Peebles Arizona flora. University of California Press, Berkeley. 1085pp. Martin P. S., D. Yetman, M. Fishbein, P. Jenkins, T. R. Van Devender, and R. K. Wilson Gentry's Rio Mayo plants - the tropical deciduous forest and environs of northwest Mexico. The University of Arizona Press, Tucson. 557pp. Mielke J Native plants for southwestern landscapes. University of Texas Press, Austin. 310pp. Powell M. A Trees and shrubs of Trans -Pecos Texas including Big Bend and Guadalupe Mountains National Parks. Big Bend Natural History Association, Inc. 536pp. Roberts N.C Baja California plant field guide. Natural History Publishing Company, La Jolla. 309 pp. Sacamano C. M. and W. D. Jones Native trees and shrubs for landscape use in the desert southwest. The University of Arizona, College of Agriculture, Cooperative Extension Service, Bulletin A -82, Tucson. 4Opp. Schmutz E. M. and L. B. Hamilton Plants that poison. Northland Press, Flagstaff, AZ. 338pp. Standley P. C Trees and shrubs of Mexico. Contributions to the U.S. National Herbarium 23. Steinman V. W. and R. S. Felger The Euphorbiaceae of Sonora, Mexico. Aliso 16(1):1-71. Turner R. M., J. E. Bowers, and T. L. Burgess Sonoran Desert plants - an ecological atlas. The University of Arizona Press, Tucson. 501pp. Vines R. A Trees, shrubs and woody vines of the southwest. University of Texas Press, Austin. 1104pp. Warnock B. H Wildflowers of the Big Bend country, Texas. Sul Ross State University, Alpine, Texas. 157pp. Figure 8. Jatropha cordata in tropical deciduous forest near Warnock B. H Wildflowers of the Guadalupe Moun- Alamos, Sonora. March tains and the sand dune country, Texas. Sul Ross State University, Alpine, Texas. 176pp. Wiggins, I. L. in Shreve F. and I. L. Wiggins Vegetation and flora of the Sonoran Desert. Stanford University Press, Stanford, California. 1740pp. Back. Issues Available All back issues of Desert Plants are available through the Desert Plants office. Most issues sell for $5.00. Two exceptions are Volume 4 (1-4) Biotic Communities which is $25.00 and Volume 12 (2), Flora of the Tucson Mountains which is $ A listing of the contents of each issue is available on request. (520) Complete your set. Order your missing back issues.