Agaves of Arizona

RON PARKER Agaves of Arizona part II While the first Agaves of Arizona installment featured naturally occurring Agaves definitively placed in one subgenus (Agave) or the other (Littaea), our second installment continues with a venture into the somewhat more tenuous realm of naturally occurring hybrids and anthropogenic (literally, man-made) cultivars, in other words, the fun stuff! A peek back at Part I in vol. 89-6 might lend a sense of continuity, as reference is made to several taxa previously discussed. Please note that range maps exclusively represent sites we have personally vis- ited and documented. Naturally Occurring Hybrid Agaves Agaves hybridize wherever they meet, provided they have overlapping bloom times and pollinators. There are three named hybrids in Arizona, and each is a cross between one of the first group (Agave Aga- ves) with one of the second (Littaea Agaves), resulting in progeny that look quite different from either parent. In each case, these hybrid Agaves are extremely rare. Many additional habitat hybrids, which bear some resemblance to one parent or the other, remain undescribed more times than not. Agave ×arizonica was originally discovered in the 1. Agave ×arizonica, one of only two known examples 1960s, and Howard Scott Gentry himself apparent- in habitat. ly failed to realize he had come across the naturally occurring hybrid, A. chrysantha × A. toumeyana, instead aligning the taxon with A. utahensis, presumably due to a similar racemose inflorescence. This may be the world’s rarest named Agave, as we know of only two living examples in habitat, miles apart in very remote sections of the New River Mountains (Fig. 1). A. ×arizonica seems poorly adapted to the harsh envi- ronment in which its parents reside. Sun and heat don’t seem at issue, but inadequate hydra- tion resulting from prolonged drought condi- tions has taken an unfortunate toll on habitat populations since its discovery. Though scarce in habitat, it offsets freely when adequate- ly watered in cultivation, and is frequently available from Desert Botanical Garden plant sales, and less commonly at nurseries. It is an extremely attractive small Agave, equally at home when cultivated in ground or containers. We have found a single example of a back- crossed Agave ×arizonica × A. toumeyana var. bella in habitat (Fig. 2). 2. Agave ×arizonica × A. toumeyana var. bella habitat hybrid. 20 Author Copy CACTUS AND SUCCULENT JOURNAL delicate and vulnerable, with nar- row leaves and no protective mar- ginal spines. Unlike its seed donor parent, leaves are not filiferous. When cultivated, A. schottii var. treleasei offsets prolifically, and is available in the retail nursery cir- cuit from time to time. Agave ×ajoensis is also rare, found only at a single locale at Organ Pipe National Monument in extreme southern Arizona, where A. deserti var. simplex and A. schottii share habitat. Once considered conspecific with A. schottii var. treleasei, A. ×ajoensis was discovered to be distinct, and subsequently described by Wendy C. Hodgson (2001). Not surprisingly, it looks a great deal like A. schottii var. treleasei, only much lighter in color. Unfortunately, it is very diffi- cult to find in the trade, and the only known habitat population is currently under siege from eri- ophyid mites. This pernicious 3. Distribution of hybrid Agave in Arizona: A. ×arizonica ●, microscopic scourge scars leaf sur- A. schottii var. treleasii ●, A. ×ajoensis ●. faces, interferes with reproduction, and even kills its hosts. Agave ×ajoensis is known to back-cross with A. deserti var. simplex. 4. Agave schottii var. treleasii from the Santa Catalina Mountains. Agave schottii var. treleasei, currently considered a variety of A. schottii, is actually an A. schottii × A. chrysantha hybrid. It is nearly as scarce as A. ×arizonica in habitat, growing in a few small clumps in the Santa Catalina Mountains near Tucson (Figs. 3 & 4). 5. Agave ×ajoensis growing in Organ Pipe National This 35–55 cm dark green Agave actually looks rather Monument. 2018 VOLUME 90 NUMBER 1 Author Copy 21 Domesticated Agaves There are five named Agave taxa in Arizona, which we consider pre-Columbian cultivars. We associate these Agaves with indigenous pre- Columbian Native Americans, who presumably hybridized, selected, gardened and farmed these plants as sources of food, fiber, beverage, and building material, among other things. All feature a paniculate inflorescence. These Agaves are either sterile or reproductively compromised, and many are still growing right where they were planted some 700–1000 years ago. Some may be sterile, but all offset prodigiously. Pre-Columbian cultivars are really a lot of fun to chase out in habitat, because they’re always found near archeological sites, usually in small groups of three to thirty plants, almost always between 750–1500 m elevation along flats or gentle slopes, in what 6. Distribution of domesticated Agave in Arizona: A. murpheyi ●, generally present as garden A. delamarteri ●, A. phillipsiana ●, A. verdensis ●, A. yavapaiensis ●. settings (Fig. 6). Oft times, we’ll encounter terraces or an ancient dwelling, then look for associated Agaves, or perhaps just the reverse. To date we have found more than 330 such sites across Ari- zona, many of which were previously unknown. Once we grasped the concept of an intelligence behind their locales, we had a far easier time ferreting them out — best Easter egg hunt ever. Agave murpheyi is the very first Arizona Agave recognized as a pre-Columbian cultivar, associated with indigenous Native Americans. This came to light as botanists and archeologists collaborated in the mid-1980s to uncover an association with ancient Hohokam archeological sites. Of A. murpheyi, Gentry (1952) writes "some of the clones appear to have been associated with old Indian living sites", so he may have suspected its status as domesticated, but apparently wasn't ready to commit, probably for lack of evi- Agave murpheyi from the Lake Pleasant area. dence at the time he penned his great tome. 7. 22 Author Copy CACTUS AND SUCCULENT JOURNAL 8. Hohokam archeological site high above an Agave murpheyi patch. Outside the valley, A. murpheyi is rare and nearly unknown, but in the Phoenix area groups of these 80–110 cm plants with ascending, dark green leaves are a common sight, often gracing medians and park- ways, rather like A. palmeri is utilized in the Tucson area. We have found A. murpheyi at Sierra Ancha, the Tonto Creek area, and close to the Mexican border, where it was reportedly once prevalent, but most are now found around Lake Pleasant and the New River area in startlingly harsh habitat that would turn many Agaves to ash (Fig. 7). It is the only Arizona pre- Columbian cultivar not endemic to our state, having also been found at several sites in northern Mexico. Not sterile, but reproductively compromised, A. murpheyi does produce small quantities of seed, along with copious numbers of bulbils, small plantlets that develop directly on bloom stalks (Fig. 9). Sim- ilar appearance and bulbil production have long led to speculation that A. murpheyi may be an A. angusti- folia hybrid, which reports of recent next-generation sequencing analysis conducted by Andrew Salywon Agave murpheyi bulbils. and Wendy Hodgson (2013) of the Desert Botanical 9. Garden apparently confirm. Other parts of the murpheyi equation remain a mystery, but look toward at Agave murpheyi is known to hybridize with A. least one putative parent that contributed cold hardi- chrysantha. ness to the mix. 2018 VOLUME 90 NUMBER 1 Author Copy 23 10. Agave delamateri from the heart of Salado country. A second Arizona pre-Columbian cultivar, Agave delamateri, was officially added to our catalog by Wendy Hodgson and Liz Slauson (1995). Original- ly discovered by Susan D. McKelvey, and named A. repanda by famed botanist William Trelease in 1929, he declined to publish for reasons unknown, and the ghosted taxon was subsequently misidentified by Gentry, who at one time considered it synonymous with A. palmeri, and A. chrysantha at another. A. delamateri is the most common of the Arizona pre-Columbian cultivars, in fact far more common than all others combined. From another perspective, it is actually more common than eight of the seventeen species considered in this catalog. To date we have found it at more than 200 sites, and believe there are still more waiting to be discovered. It’s a mid-sized Agave, 70–100 cm, with an upright posture, blue and banded (Fig. 11), associated primarily with ancient Salado Native Americans in and around the Roosevelt 11. Agave delamateri with sharply ascending leaves. Lake region (Fig. 10). A delamateri is also found at Sierra Ancha and the Verde Valley. Although seed sterile, Agave delamateri does pro- This is a really tough Agave, often found in harsh, duce pollen, and has been found to hybridize with low elevation locales where other Agaves might per- A. chrysantha and A. murpheyi, although A. murpheyi ish. It is sterile, but offsets freely and has been culti- hybrids are a likely product of ancient Salado hor- vated by the Desert Botanical Garden for quite some ticultural intervention. We may have found A. dela- time, and they occasionally offer it for sale. A delama- materi × A. verdensis hybrids as well, but this remains teri is also found at Sierra Ancha and the Verde Valley. unconfirmed. 24 Author Copy CACTUS AND SUCCULENT JOURNAL 12. Sinagua cliff dwelling, associated with several Agave phillipsiana patches country near Sedona and south of Prescott. Quite similar to A. delamateri, A. phillipsiana seems more closely aligned with the ancient Sinagua culture than the Sal- ado (Fig. 12). Like its close cousin, it is sterile and boasts an expansive distribution range, though it is far less common.

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