Federal Register / Vol. 71, No. 117 / Monday, June 19, 2006 / Rules and Regulations 35195 DEPARTMENT OF THE INTERIOR Weber described this species in the eastern Pinal County, and northeastern ‘‘Cactus and Succulent Journal’’ in 1970 Pima County. Agave toumeyana ssp. Fish and Wildlife Service (Gentry and Weber 1970). This bella is restricted to the eastern slope of perennial succulent has leaves growing the Bradshaw Mountains in eastern 50 CFR Part 17 from the base in a small basal rosette Yavapai to northwestern and central to RIN 1018–AI79 (i.e., an arrangement of leaves radiating southern Gila County, and northeastern from a crown or center), and is Maricopa to northern Pinal County. Endangered and Threatened Wildlife approximately 20–35 centimeters (cm) A comparison of plant characters and Plants; Delisting of Agave (8–14 inches (in)) high and 30–40 cm showed Agave arizonica to be arizonica (Arizona agave) From the (12–16 in) wide. The leaves are dark intermediate to the other two agave Federal List of Endangered and green with a reddish-brown to light gray species with which it is always found in Threatened Wildlife and Plants border extending nearly to the base, association (DeLamater and Hodgson approximately 13–31 cm (5–12 in) long 1986). Pinkava and Baker (1985) AGENCY: Fish and Wildlife Service, and 2–3 cm (1 in) wide. The slender, suggested that plants recognized as Interior. branched flowering stalk is 2.5–4 meters Agave arizonica may be the result of ACTION: Final rule. (m) (8.2–13 feet (ft)) tall with urn- continuing production of hybrid shaped flowers 25–32 millimeters (mm) individuals rather than a distinct SUMMARY: We, the U.S. Fish and (1 in) long (Hodgson 1999). Some Wildlife Service (Service), under the species, based on observations that plants, including Agave arizonica, are hybrid individuals are found only Endangered Species Act of 1973, as able to produce copies of themselves amended (Act), have determined that it where the ranges of the putative parents without sexual reproduction. These overlap; they are found only in random, is appropriate to remove Agave copies (clones) may remain physically arizonica (Arizona agave) from the widely scattered locations of individual connected to the original plant plants and clones; their putative parents Federal List of Endangered and (vegetative offsets) or may be physically Threatened Wildlife and Plants. This have overlapping flowering periods; separate plants. Agave arizonica’s morphological determination is based on a thorough Agave arizonica is found on open review of all available data, which characters are intermediate between the slopes in chaparral or juniper grassland putative parents; and, they appeared to indicate that this plant is not a discrete in Gila, Maricopa, and Yavapai counties taxonomic entity and does not meet the be subfertile (reduced fertilization), between 1,100–1,750 m (3,600–5,800 ft) producing pollen with a low percent of definition of a species under the Act. in elevation. The plants are often found stainability (a measure of pollen Evidence collected subsequent to the associated with native junipers viability). Agave arizonica has the same listing indicates that plants attributed to (Juniperus spp.), mountain mahogany chromosome count ((2n) of 60) as both Agave arizonica do not constitute a (Cercocarpus montanus), Opuntia spp., of its parents which allows for distinct species but rather are sotol (Nolina microcarpa), and banana continued reproduction with its parents individuals that have resulted from yucca (Yucca baccata), among other (backcrossing). Polyploidy (a genetic recent and sporadic instances of species common to the chaparral/ variation wherein an individual plant hybridization between two species. juniper-oak transition (Hodgson and has more than the two normal sets of Current taxonomic practice is not to DeLamater 1988). There are estimated to homologous chromosomes) is one factor recognize such groups of individuals as be fewer than 100 plants in the wild, a species. Since Agave arizonica is not occurring mainly on the Tonto National in determining if a hybrid between two recognized as a species, it no longer Forest and a few locations on private species can become genetically stable. qualifies for protection under the Act. property. Agave arizonica plants are This condition is not present in the genetic constitution of Agave arizonica. DATES: This rule is effective July 19, associated with shallow, cobbled, and 2006. gravelly soils on strongly sloping to very Survey work continued in areas that steep slopes and rock outcrops on mid- supported populations of the two parent ADDRESSES: Supporting documentation species. These surveys resulted in the for this rulemaking is available for elevation hills and mountains. The soils are well-drained and derived from a discovery of two clones in the Sierra public inspection, by appointment, Ancha Mountains, 100 miles disjunct during normal business hours at the variety of rocks, including granite, gneiss, rhyolite, andesite, ruffs, from the New River Mountain locations. Arizona Ecological Services Field Office limestone, sandstone, and basalt To date, plants and clones have been of the U.S. Fish and Wildlife Service, (Hodgson and DeLamater 1988). Plants identified in three areas on the Tonto 2321 West Royal Palm Road, Suite 103, typically flower from May to July. National Forest (New River Mountains, Phoenix, Arizona 85021–4951. Field studies on Agave arizonica Sierra Ancha Mountains, and the FOR FURTHER INFORMATION CONTACT: began in 1983. A natural distribution Humboldt Mountains). The New River Mima Falk, U.S. Fish and Wildlife study was not finalized until August population is the most numerous, Service, located in the Arizona 1984 (DeLamater 1984), after the final located 17.94 kilometers (km) (10.7 Ecological Services Tucson Sub-office, listing rule (49 FR 21055, May 18, 1984) miles (mi)) west-northwest of the Sierra 201 North Bonita Avenue, Suite 141, was published. Surveys for this study Ancha population. Only one individual Tucson, Arizona 85745 (telephone 520/ were conducted in the New River was found in the Serra Anch Mountains 670–6150 ext. 225; facsimile 520/670– Mountains, and by 1984, ten new clones (Tra¨bold 2001). The Humboldt 6154). were found in these mountains. These Mountains support a population of SUPPLEMENTARY INFORMATION: were individual clones of 2–5 rosettes. Arizona agave, as well as another agave All of the clones occurred together with hybrid. This different hybrid agave is Background two other agaves, Agave toumeyana ssp. produced from a cross between A. Agave arizonica, a member of the bella and A. chrysantha, neither of toumeyana ssp. toumeyana and A. agave family, was first discovered by which is considered rare. A. chrysantha chrysantha (Pinkava and Baker 1985). J.H. Houzenga, M.J. Hazelett, and J.H. is found in southern and eastern That hybrid is a triploid (3n=90), and Weber in the New River Mountains of Yavapai County, through much of Gila therefore has a different chromosome Arizona. Drs. H.S. Gentry and J.H. and Maricopa counties, northern and count than Agave arizonica. VerDate Aug<31>2005 15:59 Jun 16, 2006 Jkt 208001 PO 00000 Frm 00053 Fmt 4700 Sfmt 4700 E:\FR\FM\19JNR1.SGM 19JNR1 wwhite on PROD1PC61 with RULES 35196 Federal Register / Vol. 71, No. 117 / Monday, June 19, 2006 / Rules and Regulations The Desert Botanical Garden (DBG), phenotypic (visible) variations; not all number (2n=60) with the putative in Phoenix, initiated ecological studies seedlings presented ‘pure’ Agave parents, indicating that there are no of Agave arizonica in the mid-1980s arizonica traits. The fact that Agave chromosomal barriers (i.e., reproductive through 1994. They conducted arizonica can be reliably produced by isolating mechanisms) in place to numerous surveys on the Tonto crossing the putative parents ex situ facilitate genetic stability, (2) flowering National Forest, collected seeds in situ lends support to the hypothesis that periods of the putative parents overlap, (in the natural or original environment), Agave arizonica is a recurring F1 (3) morphological characters of Agave conducted experimental crosses in situ hybrid. All evidence supports that arizonica are intermediate with those of and ex situ (in an artificial Agave arizonica individuals are derived the putative parents, (4) Agave arizonica environment), and started an ex situ from crosses between different species. only occurs where there is overlap with collection. DBG’s work has shown that In other words, each individual Agave the putative parents, (5) it appears to be Agave arizonica can produce viable arizonica was created spontaneously subfertile, producing pollen with low seed. In 1985, three different crosses and independently from separate percent stainability, (6) Agave arizonica were performed on clone #52, in situ, crossings of the putative parental can be created, ex situ, by crossing the using flowers from different panicles species (M. Baker, pers. comm. 2004). putative parents, indicating that there (flower stalks). One cross used frozen Agave arizonica plants are rare in the may be no unique genetic characters pollen collected from Agave arizonica at wild. The likelihood is low that two of associated with these plants, and (7) it the DBG, the second cross was self- these plants would breed with one has not, to our knowledge, reproduced fertilization of clone #52, and the third another because it is unlikely that two sexually in the field. cross was uncontrolled outcrossing of such plants would be close enough to Previous Federal Action clone #52 (flowers were left open to be one another and bloom in the same year. Clones still attached or near to the pollinated by various donors). Seed was Federal Government action parent plant may produce flowers at the collected from all three crosses. Cross #1 concerning Agave arizonica began with same time, but spatially separated produced 250 seeds, cross #2 produced section 12 of the Act, which directed the clones may not all bloom at the same 20 seeds, and cross #3 produced a large Secretary of the Smithsonian Institution time.