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Hesperaloe

Contributor: Steven P. McLaughlin, Office of Arid Lands Studies, University of Arizona.

Copyright © 1995. All Rights Reserved. Quotation from this document should cite and acknowledge the contributor.


  1. Common Names
  2. Scientific Names
  3. Uses
  4. Origin
  5. Crop Status
  6. Botany
    1. Taxonomy
    2. Morphology
    3. Physiology
    4. Reproduction
  7. Crop Culture (Agronomy/Horticulture)
    1. Biomass Production
    2. Harvest and Processing
  8. Germplasm
  9. Key References
  10. Selected Experts

Common Names

English: (none)

Spanish: samandoque

Scientific Names

Species: There are two species of interest:
1. Hesperaloe funifera (Koch) Trel.
Syn: Yucca funifera Koch, Hesperaloe davyi Baker
2. Hesperaloe nocturna H. S. Gentry
Family: Agavaceae

Uses

The strong fibers (fiber bundles) of H. funifera are used locally in northern Mexico for cordage products. Both H. funifera and H. nocturna are used sporadically in the southwestern United States as ornamentals. Recent interest in Hesperaloe species, however, is focused on the potential use of the fibers for paper-making. Both H. funifera and H. nocturna produce long (3-4 mm), thin (14-17 micron) fibers. By way of comparison, the fibers of Hesperaloe are comparable to those of softwoods in their length but are less than half as wide. The fibers of Hesperaloe produce a paper with exceptional tensile and tear strength. Such fibers could be used either in specialty papers with high-strength requirements, such as currency papers, bible papers, tea bags, and filters, or they could be blended with other fibers to increase the strength and improve the texture of a variety of paper products, including writing papers, tissue and towel products, and papers manufactured using secondary (recycled) fiber.

Origin

Hesperaloe funifera is endemic to the Chihuahuan Desert region of northern Mexico. The plant is found in several small, disjunct populations in the states of Coahuila, Nuevo Leon, and San Luis Potosi. Hesperaloe nocturna is endemic to the Sierra de la Madera, an outlying mountain range of the northern Sierra Madre Occidental in northeastern Sonora, Mexico.

Crop Status

Hesperaloe is strictly an experimental crop at this time. Experimental plots of H. funifera were established at the University of Arizona's Bioresources Research Facility (BRF), Tucson, Arizona, in 1988, and at the Maricopa Agricultural Center (MAC), Maricopa, Arizona, in 1994. Experimental plots of H. nocturna were established at BRF in 1990. There are plans to establish ca. 20 acres of additional plots, including both species, by the end of 1995 at MAC.

Botany

Taxonomy

Hesperaloe is a small genus of 5 species, two of which are currently unnamed, all native to northern Mexico. One species, H. parviflora (Torr.) Coult., extends into central and southern Texas, and is used extensively as a landscape plant; it is marketed under the name "red yucca". Gregg Starr, a Tucson horticulturalist, is in the process of naming the two new species from Mexico. Hesperaloe appears to be most closely related to Yucca, differing primarily in the structure of the inflorescence.

Morphology

Hesperaloe spp. are acaulescent, densely caespitose plants consisting 1 to several tightly spaced rosettes. Each rosette consists of a single apical meristem which produces several leaves in a spiral phylotaxy. After 3-4 years under cultivation the vegetative meristem converts to a reproductive meristem which produces a 2-3 m tall inflorescence. Unlike "century plants" (Agave spp.), the leaves of Hesperaloe rosettes persist for several years after flowering. The leaves of H. funifera are narrowly lanceolate, rigid, marginally filiferous, 1-2 m long, 2-4 cm wide, thick at the base, and tapered toward the apex. The leaves of H. nocturna are linear, lax, marginally filiferous, 1-1.5 m long, 1-1.5 cm wide, and gradually tapered to the apex from a narrow base. The fresh leaves of both species consist of 30-33% dry matter and ca. 10% dry fiber.

Physiology

Both Hesperaloe species are obligate CAM (Crassulacean acid metabolism) plants. Detailed studies on gas exchange of Hesperaloe species demonstrate that the plants are capable of positive CO2 uptake all year long expect under conditions of high cloud cover and low temperature. Maximum instantaneous photosynthetic rate are low (3-8 micromol CO2/m²/s), but integrated physiological water-use efficiency is high (2-10 mmol CO2/mol H2O/d). Maximum photosynthetic rates and WUE appear to somewhat higher for H. funifera than for H. nocturna. Hesperaloe funifera shows a marked decrease in photosynthetic rate during the summer followed by peak rates in the fall; H. nocturna shows less seasonal variation in photosynthetic rates.

Reproduction

Both Hesperaloe species produce tall, sparsely branched panicles. The species are indeterminate with a long flowering period lasting from May into October. The terminal portion of the main stem and entire length of the lateral branches produce nodes spaced 1-2 cm apart. Each node produces several flowers sequentially. The flowers of H. funifera are campanulate with erect, greenish-white tepals 19-25 mm long; those of H. nocturna have whitish, reflexed tepals 15-22 mm long. The three-carpeled fruits of each species produce 6 rows of flat, black seeds. The seeds of H. funifera (43 seed/g) are about half the size of those of H. nocturna (20 seed/g). Both species produce large numbers of flowers (ca. 1000-10000 flowers per inflorescence) and have a low fruit set (0.5-4.0%); both appear to be obligate outcrossers.

Crop Culture (Agronomy/Horticulture)

Biomass Production

Biomass production trials for H. funifera were established at BRF in 1988. Initial growth rates in these CAM plants are very slow. Plots planted to densities of 6750, 13500, and 27000 plants/ha produced just 0.7, 0.8, and 1.6 Mg FW/ha, respectively, at the end of their first year of growth. Standing crops were 22.3, 44.1, and 70.2 Mg FW/ha, respectively, after 3 years, and 87.4, 136.3, and 192.5 Mg FW/ha after 5 years. Harvested plants can regrow to produce subsequent harvests. After 2 years of regrowth following an initial harvest at 5 years, plots produced 45.7, 73.0, and 112.3 Mg FW/ha, respectively, in the low-, medium-, and high-density plots. Biomass production trials for H. nocturna were initiated in 1990. Plots established at densities of 6750, 9000, 13500, and 18000 plants/ha produced standing crops at the end of 4 years of 57.8, 74.9, 90.7, and 117.0 Mg FW/ha, respectively. Current plantings at MAC are being established on 1-m beds at a density of 22000 plants/ha.

Because of their slow initial growth rate, Hesperaloe plants use water and fertilizer rather inefficiently in the first 2 years of stand establishment. After year 2, however, water-use efficiency (WUE) is high, consistent with the plants' CAM metabolism. Calculated over the first 5 years, WUE in the H. funifera production plots was 0.14, 0.20, and 0.17 Mg DW/ cm, respectively, in the low-, medium-, and high-density plots. Averaged over the following 2 years of regrowth, WUE increased to 0.21, 0.33, and 0.24 Mg DW/cm, respectively. Averaged over their first 4 years of growth, WUE in the H. nocturna plots was 0.11, 0.15, 0.18, and 0.12 Mg DW/cm, respectively, in the low- to high-density plots. By comparison, C3 biomass crops such as alfalfa grown in Arizona have WUEs approximately 0.08-0.10 Mg DW/cm.

Harvest and Processing

Equipment for harvesting and decortication of Hesperaloe leaves is currently being developed. Decortication, which involves stripping away the nonfibrous tissues from the leaves, appears to be critical to producing a raw material that gives a high pulp yield.

Germplasm

Seed collections are maintained at the University of Arizona, BRF. There are currently no commercial sources of Hesperaloe seed.

Key References

Selected Experts

Steven P. McLaughlin, Office of Arid Lands Studies, University of Arizona, Tucson, AZ 85721. Tel: 520-621-8577, 520-741-1691; FAX: 520-741-1468; Email: spmcl@ag.arizona.edu.

Damian A. Ravetta, Facultad de Agronomia, Universidad de Buenos Aires, Av. San Martin 4453, Buenos Aires 1417, Argentina. Tel: 011-541-522-1006; FAX: 011-541-521-1384

Contributor: Steven P. McLaughlin, Office of Arid Lands Studies, University of Arizona.

Copyright © 1995. All Rights Reserved. Quotation from this document should cite and acknowledge the contributor.


Last update Tuesday, February 24, 1998 by aw