Index of articles:
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    In 1871 Sir Joseph Hooker at Kew wrote, 'Of all cultivated plants none are more difficult to name accurately than the species of agave, partly because of the imperfection of published descriptions and more from the impossibility of fixing their characters by words'. The confusion and argument continues to this day and it is still not uncommon to see in collections and sales lists a particular name applied to plants that quite obviously have different features. I have good experience of this type of problem in that a particular plant in my collection labelled as agave warelliana has been 'positively' identified by a fellow enthusiast as being agave pedunculifera whilst I have seen an identical plant offered by a nursery online as agave attenuata v. serrulata and recently saw a photo from the Botanical Gardens in Amsterdam of this plant labelled as agave hartmanii. There are so many unresolved issues that agavologists will be kept busy for some time to come.

    Linnaeus founded the genus in 1753 and recognised four species: americana; vivipara; foetida ( now moved to Furchraea ) and virginica ( now moved to Manfreda ). Most agave names were added in the 18th and 19th century and prominent amongst the experts at the that time were Salm-Dyck who revised the genus between 1834 and 1859 and ultimately described 45 species in 5 sections. This work was developed further by von Jacobi between 1864 and 1867 when he described 78 species and many varieties. The problems with these works and those of other authors at that time is that names were based on often immature potted plants grown in cultivation in various European collections in very non Mexican conditions. Slight variations in appearance, be it in the size of plant or shape of leaves, led to yet another species or variety being born and so to ever bigger lists. There was no scientific back up provided in the shape of illustrations or descriptions of preserved specimens. Baker in 1888 listed 138 species in 3 subgenera including Manfreda but although he was fortunate in that he was able to observe flowering agaves he did not use flowering characteristics in his classification. By this time illustration of the plants was relatively commonplace and was of great help to the taxonomists of the time and also to their successors. Prior to 1934 agaves were classified as Amaryllideae but at that time Hutchinson at Kew combined them with yuccas, manfredas, furchraeas, hesperaloes and others in the new family grouping of Agavaceae.

    'The Big Three' as far as agave nomenclature was concerned were William Trelease, Alwin Berger and Howard Scott Gentry. Trelease was the director of the Missouri Botanical Gardens in St. Louis and was the first major taxonomist who travelled quite extensively in Mexico, the Caribbean and parts of South America and observed plants actually growing in the wild. He produced several works between 1907 and 1924 describing agaves both on the mainland and those of the various Caribbean islands. He made little use of floral characteristics in identifying species and continued the traditional taxonomy of the 19th century described by Gentry as the concept of 'out of difference comes species'.
    In Europe Alwin Berger organised the botany of agave in his great work 'Die Agaven' published in 1915. He described 274 species divided into 3 subgeneric groups, Littaea, Euagave and Manfreda, these being split further into sections and subsections. He tended to follow the traditional concepts in naming species although he did make some use of flowering characteristics at section level. He was the curator at the Hanbury Gardens in La Mortola near Ventimiglia in northwestern Italy, close to the French border. There was a rich living collection of plants growing here in a climate more favourable to normal development and maturation of agaves.
    These preceeding taxonomists can be described on the basis of the proliferation of agave names under their authorship as 'splitters'. In 1982 there appeared a mammoth work on agaves titled ' Agaves of Continental North America' by Howard Scott Gentry which was reprinted in 1998 with a few modifications. This is regarded now as the standard reference work on these plants although it does not cover the Caribbean area. Gentry names 136 species which with subspecies, varieties and forms total 197 taxa. There are 2 subgeneric groups, Littaea and Agave, divided on the basis of differing flower characteristics. Unlike his predecessors Gentry was very much a 'lumper' and fostered the broader species concept. He travelled widely and described plants on the basis of extensive work in habitat and he was also the first to make extensive use of flowering characteristics in nominating species. He also emphasised the fact that agaves are very variable in their growth characteristics and appearance may depend very much on geography and climate so that one cannot always take the appearance of a single plant at face value as the earlier European taxonomists tended to do.

    Since Gentry the most prolific agave author is Bernd Ullrich who has written several important papers between 1990 and 1993 reassigning some names from Gentry's classification and also reassigning plants to different family groups on the basis of new evidence. He has also introduced 2 new family groupings into the subgenus Littaea.

    The Caribbean agaves, ignored by Gentry, were initially classified by Trelease in 1913 and included in his work by Berger. Further nomenclatorial work on these plants has been done by Dutchmen P. Waagenaar Hummelinck in a series of articles between 1936 and 1993 and D.O.Wijnands in 1983 plus R.A. Howard in 1979.
    I think that a very important point often forgotten ( perhaps too conveniently in some cases ) is the fact that there exist many intermediate forms between various agaves as well as many hybrid forms so that it is not always possible to place a plant in a specific category as defined by Gentry and other authors. As someone once pointed out to me ' Plants do not grow in habitat with labels on them ' and I think this is a very important and relevant statement. This is of course in addition to the fact that in Europe we may be trying to identify plants grown in pots and in very non habitat like conditions. The group Marginatae is especially difficult in this respect with a proliferation of various hybrids and intermediate forms making life very difficult and quite confusing for those trying to name individual plants. Agave victoria-reginae for example mixes readily with agave scabra (= agave nigra ) and with lechuguilla (= agave victoriae-reginae f. viridis), whilst lechuguilla itself is involved in many mixed forms with agave lophantha. Lophantha in turn mixes readily with various forms of ghiesbreghtii and xylonacantha, many of these plants being given new names eg. agave simonii ( = lechuguilla X xylonacantha ). Agave filifera and schidigera have also been involved in various mixes giving rise to agave leopoldii ( = filifera X schidigera ) and agave taylorii ( = filifera X geminiflora ). A recipe for confusion if ever there was one !!!
     

    A classical example of categorising a plant erroneously is the plant illustrated above, with shiny green leaves and pale median stripe. This I have seen many a time wrongly labelled Agave obscura when it appears in fact to be a form of Agave lophantha . The true Agave obscura as originally described by Schiede in 1830 is quite different and has recently been considered as the same plant as Agave polyacantha v. xalapensis. ( See below ***** ).

     
    There is also a plant doing the rounds as Agave titanota ( see above picture ) but is quite unlike the plant defined by Gentry which has grey-white leaves. Initially considered a separate entity and still considered as such by many, it has been found growing alongside the true titanota in habitat and could represent a variant in a highly polymorphic and variable species. The debate continues.
    This plant is also sold as sp. FO-076, sp. Sierra Mixteca and sp. Nr.1.

    Agave titanota ( the real thing)

    This subgenus is recognised by Gentry (1982) on the basis of a spicate inflorescence where the flowers cling to the stalk in pairs or clusters.

    Gentry organised this subgenus into 8 groups comprising 54 species and a total of 71 taxa including subspecies, varieties and forms. Since then a number of revisions have been made primarily by Ullrich.

    Important changes proposed since Gentry (1982) :

    Agave albomarginata from the Marginatae group and closely related to A. lechuguilla was previously considered a cultivar from the Huntingdon BG. It was found in Queretano ( Hernandez 1994 ).

    Agave attenuata and pedunculifera regarded as part of the same variable complex ( Ullrich 1990d) :

    Agave bracteosa transferred from Choripetalae group to new Serrulatae group ( Ullrich 1990d) :

    Agave celsii considered as synonym for A. mitis ( Ullrich 1993a ) :

    Agave colimana reverts back to A. ortgesiana ( Ullrich 1991a) :
     
    Agave ellemeetiana was originally placed by Gentry (1982) in the group Choritepalae together with A. bracteosa and A. guiengola. At that time habitat was unknown and the neotype was assigned to a plant at the Royal Botanical Gardens at Kew in London. In 1991 Ullrich placed this agave in his group Attenuatae, considering it closely related to A. pedunculifera, now considered a subspecies of A. attenuata.
    In the C&S.J.(U.S.), nr.4 (2002) it was reported that A. ellemeetiana has been 'refound' in Oaxaca (Garcia-Mendoza). The form growing there has denticulate margins. In 2007 there were reports of finding it in Veracruz and this is now considered the main habitat of this plant. In fact in 1920 Trelease had suggested Veracruz as the likely habitat of this species.The specimens from Veracruz have unarmed margins and slightly longer leaves than those in Oaxaca.
     
    Agave felgeri transferred from Filiferae group to Parviflorae group ( Ullrich 1991c) :
     
    Agave fernandi-regis (Berger), a form of A. victoriae-reginae, reverts to A.nickelsiae (Gosselin) (2011).
     
    Agave hartmanii identified as synonym of A. parviflora ssp. flexiflora (Ullrich 1990i) :
     
    Agave multifilifera and agave schidigera reclassified as subspecies of A. filifera ( Ullrich 1992 l) :
     
    Agave nizandensis transferred from Amolae group to new Nizandensae group ( Ullrich 1991b) :
     
    Agave obscura is identified as synonymous with A. polyacantha v. xalapensis ( Chazaro- Basanez 1981 and Ullrich 1992 ).
    See below *****
     
    Agave pedunculifera now considered synonym of A. attenuata ssp. dentata ( Ullrich 2006)

    Agave stricta reclassified as subspecies of A. striata ( Ullrich 1990b ; 1991d) :

    Agave warelliana, belonging to the Polycephalae group, found for the first time as a wild plant at the Pico de Oriba volcano in Veracruz . Found also at La Trinitaria, Chiapas, Mexico by Garcia Mendoza and in Guatemala ( Garcia Mendoza & Lott 1994 ) . Previously the plant had been described by Baker from a specimen at the Reigate collection of Mr. Wilson Saunders. The neotype specimen had been designated by Gentry in 1982 from a plant from the Hanbury Gardens at La Mortola prepared by Berger in 1912.
     
    Ag. warelliana in habitat
    © Abisaí García Mendoza
    © Missouri Botanical Garden
     
    Newly named species :
     
    Agave albopilosa from Sierra Madre Oriental ( Cabral, Villareal and Estrada 2007). It belongs to the subgenus Littaea and family group Striatae. A distinguishing feature is a ring of hairs growing near the tip of each leaf, below the terminal spine :
     
    Agave arcedianoensis ( originally Agave colimillensis ) ( Chazaro, Valencia and Vazquez 2007) ; a close relative of A. angustiarum. Found in Colimilla and Rio Verde, Jalisco :
     
    Agave chazaroi from Tequila,Jalisco, described by Vazquez in 2007. There are grounds to believe that this plant may be the long lost A. bakeri :
     
    Agave doctorensis from Sierra El Doctor, part of the Sierra Madre Oriental in Queretaro, Mexico. Described by Hernandez-Sandoval and Magallan-Hernandez in 2014; it comes within the group Marginatae and is related to agave glomeruliflora and agave montium sancticaroli. It has some use locally in the production of aguamiel and pulque.
     
    Agave filifera ssp. microceps from Sinaloa, Mexico ( Kimnach 1995) :
     
    Agave garciae-mendozae from Hidalgo, Queretaro and San Luis Potosi, Mexico; belonging to the Marginatae group, closely related to A. horrida and A. kerchovei ( Galvan & Hernandez 2002 ) :
     
    Agave gomez pompae from Cordoba in Veracruz,Mexico. First discovered in 2004 and subsequently described by Chazaro and Jimeno-Sevilla. It belongs to the the family group Polycephalae. It's closest relative is A. pendula :
     
    Agave gracielae from Queretaro and San Luis Potosi, Mexico. Described in 2013 by Galvan and Zamudio. Belongs to the group Striatae and is related to agave dasylirioides, agave petrophylla and agave rzedowskiana.
     
    Agave hidalgensis from Hidalgo, Mexico; belonging to the Marginatae group ( Galvan & Koch 2002 ). This name is now invalid and is regarded as an early name for A. garciae-mendozae :
     
    Agave horrida ssp. perotensis from Puebla and Veracruz, Mexico ( Ullrich 1992 d) :
     
    ***** The original agave obscura was named by Schiede in 1830. Subsequently it was ignored in turn by all the famous taxonomists such as Salm Dyck, Jacobi, Baker and Berger. The name was mentioned again by Trelease, Breitung and Gentry but appears to have referred to a different plant ,closely related to A. horrida and named by Ullrich as A. horrida ssp. perotensis. Schiede's original A. obscura is considered in work by Chazaro Basanez 1981 and Ullrich 1992 as the same plant as A. xalapensis which Gentry treated as a variety of A. polyacantha. Ullrich further proposes that the name polyacantha is a ' nomen confusum ' and should no longer be used.
     
    Agave jimenoi is newly described in 2013 by Chazaro-Basanez and Vazquez Garcia. Belongs to Polycephalae group and was found in Totonacapan, Veracruz. Closely related to A. gomez pompae, appearing to differ mainly in size.
     
    Agave kavandivi from Oaxaca. Newly described by Garcia-Mendoza andChavez-Rendon in 2013. Subgenus Littaea and family group Striatae. Very closely related to A. dasylirioides.
     
    Agave manantlanicola is a new species from western Mexico is described by Cuevas Guzmán, Santana-Michel, and Balcazar-Medina in Brittonia 64(3):330-335, 2012. It is an endemic species from the high altitude mountains of the Sierra de Manantlán in western Mexico, only found at high elevations between 2640 to 2865 m on near vertical cliffs with constant fog during the rainy season. The species belongs to the subgenus Littaea and according to post Gentry classifications to the Serrulatae group ( alongside attenuata, chrysoglossa, gilberti, nizandensis, ocahui, pedunculifera, vasquezgarciae & vilmoriniana).
     
    Agave montium sancticaroli is a new species described by Garcia-Mendoza, Jacques-Hernandez and Salazar Bravo in the Journal of the Botanical Research Institute of Texas 1 (1):79-84,2007.
    It was found in 2003-04 in the Sierra de San Carlos region, Taumalipas in Mexico. It belongs to the Marginatae group of the subgenus Littaea and is similar to agave X glomeruliflora (Berger) but is generally a larger plant than X glomeruliflora with larger and more numerous leaves.
     
    Agave parviflora ssp. densiflora is a new subspecies of agave parviflora is described by Starr & van Devender in Cactus and Succulent Journal, 83(5):224-231. 2011, published by Cactus and Succulent Society of America. It is distinguished from subspecies parviflora & flexiflora by a larger leaf size and more densly crowded flower stalk. It was found growing in small numbers east of Yecora in south eastern Sonora.
     
    Agave pintilla newly described form of agave victoriae reginae from the region of south east Durango ( Acta Botanica Mexicana 95: 65-94 (2011) ).
    In April 2007 in Succulenta, the magazine of the Belgian and Dutch Succulent Society, there appeared an article by Alsemgeest, van Roosbroeck and Walderveen describing the four major forms of agave victoriae-reginae, based on studies of these plants whilst travelling through their natural habitat. They classified the plants in four logical groups:
    1. victoriae reginae
    2. victoriae reginae f. compacta
    3. victoriae reginae f. viridis ( no leaf markings)
    4. victoriae reginae f. fernandi regis
    The full article, translated into English, is to be found here : http://www.agaves.nl/Articles/E_victoriae%20reginae.htm
    In the new article by Gonzales Elizondo et al. in 2011 agave victoriae reginae is newly reclassified as follows:
    1. victoriae reginae ssp. victoriae-reginae (western Nuevo León and eastern extreme of Coahuila
    2. victoriae reginae ssp. swobodae (southern Coahuila and northeastern Durango)
    3. nickelsiae (microendemic to southeastern Coahuila) ; replaces fernandi-regis
    4. pintilla (the most westernly distributed species in the group, restricted to southeastern Durango).
     
    Agave petrophila from Guerrero and Oaxaca, Mexico related to A. dasylirioides, originally named A. gracilis but subsequently renamed by the authors ( Garcia Mendoza & Martinez Salas 1998) :
     
    Agave rzedowskiana from Jalisco and Sinaloa, Mexico; belonging to the Striatae group, similar to A. dasylirioides and A. petrophila. ( Carrillo-Reyes, Avina & Ramirez-Delgadillo 2003 ) :
     
    Agave tenuifolia from Sierra Madre Oriental, Mexico related to A. striata ssp. striata ( Zamudio- Ruiz & Sanchez- Martinez 1995) :
     
    Agave vazquez-garciae from Sierra Manantlan, Jalisco. Belongs to Amolae group and closely related to A. pedunculifera. ( Chazaro-Basanez & Pelayo 2002 ) :
     
    Agave wendtii from Sureste de Vera-Cruz, Mexico related to A. pendula ( Chazaro-Basanez 1995) :
     

    This subgenus is recognised by Gentry (1982) on the basis of a paniculate inflorescence where the flowers appear in clusters on lateral branches. Previous authors had used the name Euagave.

    Gentry organised this subgenus into 20 groups comprising 82 species and a total of 126 taxa including subspecies, varieties and forms. Since then a number of revisions have been made by various authors.

    Important changes proposed since Gentry (1982) :

    Agave angustifolia is renamed as A. vivipara ( Wijnands 1983 ; Foster 1992 ; Smith & Steyn 1999). This name change was included by Dr. J. Thiede in his contribution to 'Handbook of Succulent Plants : Monocotyledons' published in 2001. The name change appeared not to be universally accepted and in 2003 Garcia-Mendoza & Chiang produced a paper in Brittonia in which they argued that angustifolia and vivipara are separate taxa and should not be considered one and the same plant.

     
    Agave deserti ssp. pringlei (Engelmann ex Baker) Gentry becomes A. deserti var. pringlei (Engelmann ex Baker) and Agave deserti ssp. simplex (Gentry) becomes A. deserti var. simplex (Gentry) i.e. the two subspecies Gentry recognized under A. deserti are reduced to variety status ( Hodgson 2001 ) :
     
    Agave gypsophila was described in 1982 by Gentry as a single entity in the group Marmoratae. In 2013 there has been a taxonomic status revision by Vazquez-Garciae, Chazaro-Basanez et.al. (Systematic Botany (2013) 38(2): pp320-331) and now gypsophila is considered not as a single entity but a gypsophila complex consisting of five species, four being newly named species.
    1. Agave abisaii (Vazquez-Garciae & Nieves 2013) from southern Jalisco
    2. Agave andreae (Sahagun & Vasquez-Garciae 2013) from Michoacan
    3. Agave gypsophila (Gentry 1982) from Morelos,Guerrero
    4. Agave kristenii (Vasquez-Garciae & Chazaro-Basanez 2013) from Michoacan
    5. Agave pablocarrilloi (Vasquez-Garciae, Muniz & Padilla-Lepe 2013) from Colima
     
    Agave macroculmis (Todaro) as assigned by Gentry to wild plants in habitat is now considered incorrect
    ( he himself had doubts;see 'Agaves of Continental North America' p.601 ) and Todaro's plants have been identified as a form of A. atrovirens.
    The wild plants that Gentry gave this name to are now considered as a new species and named A. gentryi (Ullrich 1990b)
    This thread developed a few years later when the name agave montana was given to plants growing together with and at higher altitudes than agave gentryi. Subsequently in some locations plants of gentryi were also found at the higher altitudes. There is currently sharp debate as to whether these are entirely separate entities or if hybrid or intermediate forms exist. There are differences in inflorescence characteristics between the two species.
     
    Ag. gentryi (left) Ag. montana (right)
    (habitat photo from Paul Spracklin)
     
    Agave neomexicana was reclassified as a subspecies of A. parryi ( Ullrich 1992) :
     
    Agave parryi v. couesii / huachucensis / truncata were all reclassified as forms of A. parryi ssp. parryi
    ( Ullrich 1992) :
     
    Agave pygmaea reclassified as subspecies of A. seemanniana ( Ullrich 1992c) :
     
    Agave scabra (Salm-Dyck) as allocated by Gentry was corrected to A. asperrima (Jacobi).
    From descriptions and photographs it was shown that Salm-Dyck's original plant was A. wislizeni (Engelmann),
    nowadays considered a form of A. parryi. The name scabra had earlier been used by another author,
    Ortega in 1797, to describe a plant subsequently reassigned to Manfreda so Salm-Dyck's use for his plant
    was invalid. ( Ullrich 1992):
     
    Agave stringens (Trelease 1920) was allocated by Gentry to the group Rigidae and descriptions were based on immature plants.
    The plant has since been 'rediscovered' by Kristen & Etter in near Guadalajarana, Jalisco (site of Trelease's type plant) and is now placed in the group Viviparae, consisting of Gentry's groups Rigidae & Sisalanae.
     
    Agave wislizeni was reclassified as a synonym for a form of A. parryi and no longer applicable to A. parrasana ( Ullrich 1992) :
     
    Newly named species :
     
    Agave abisaii ( Vasquez-Garciae & Nieves 2013) from southern Jalisco, one of the newly revised gypsophila complex belonging to the Marmoratae group. Differs from gypsophila in suckering and having narrower leaves and smaller inflorescence. The leaves when roasted are said to have anti-inflammatory properties.
     
    Agave andreae (Sahagun & Vazquez-Garciae 2013) from Michoacan, one of the newly revised gypsophila complex belonging to the Marmoratae group. Non suckering it differs from gypsophila by having more ascending leaves, larger inflorescence and flowers and growing at a higher elevation.
     
    Agave x ajoensis, ? a sterile hybrid between A. deserti var. simplex and A. schottii var. schottii, found only in the
    Ajo mountains in the Organ Pipe National Monument, Arizona ( Hodgson 2001 ) :
     
    Agave azurea (Webb & Starr 2014) from Picachos de Santa Clara, Baja California. It's closest relative would appear to be agave vizcainoensis and the two form the new section Intermediae in the author's new revision of the group Deserticolae. It is a medium-sized species with distinctive glaucous blue-green leaves that does not produce offsets, has a relatively short and narrow inflorescence, and a distinctive flower structure. This new species is a narrow endemic restricted to mostly rocky slopes and alluvial surfaces emanating from isolated mesas and peaks in an environment with strong fog influence.
     
    Agave cordillerensis from Peru,Bolivia,Ecuador and Columbia. Described by Lode and Pino in 2007 in Cactus Aventures (January 2008). The type plants are to be found in Peru and it would appear that in the past they have been mistakenly identified as agave americana or agave americana v. expansa. One of the characteristics of this plant is the inflorescence which is bent and grows almost horizontally in a comma shape.
     
    Agave delamateri from Arizona (Hodgson & Slauson 1995) :
     
    Agave grijalvensis from Chiapas, Mexico belonging to the Marmoratae group ( Ullrich 1990a) . Considered synonymous with A. kewensis (Jacobi), originally placed in group Sisalanae but transferred by Ullrich to group Marmoratae.
     
    Agave isthmensis from Chiapas and Oaxaca, Mexico related to A. potatorum and A. seemanniana v. pygmaea ( Garcia-Mendoza & Palma 1993) :
     
    Agave kristenii (Vasquez-Garciae & Chazaro-Basanez 2013) from Michoacan, one of the newly revised gypsophila complex belonging to the Marmoratae group). Differs from gypsophila in having a smaller,suckering rosette with linear leaves and growing at a lower elevation. Locally called 'maguey del piedra' the leaves are said to have anti-inflammatory properties.
     
    Agave montana from Mexico classified in the Salmianae group ( Villareal 1996)
    (NB. see above under agave macroculmis) :
     
    Agave nussaviorum ssp. nussaviorum and v. deltoidea from Oaxaca, described by Garcia-Mendoza in 2010 and related to
    A. potatorum and A. seemanniana from the group Hiemiflorae. Growth habitat is adjacent to these latter two taxa.
     
    Agave ovatifolia, from Nueva Leon, Mexico; a new species belonging to the group Parryanae and related to
    A. parrasana and A. havardiana ( Starr & Villareal 2002 ):
     
    Agave pablocarrilloi (Vasquez-Garcia, Muniz & Padilla-Lepe 2013) from Colima, one of the newly revised gypsophila complex belonging to the Marmoratae group. Has a smaller inflorescence than gypsophila and grows at lower elevations.
     
    Agave phillipsiana ,a new freely suckering species allied to A. palmeri and A. delamateri and found only in four sites within the Grand Canyon National Park in Arizona, ? a hybrid between A.palmeri and A.americana var. expansa ( Hodgson 2001 ) :
     
    Agave spatularia name given recently to population of agave parryi in San Luis de la Paz, Guanajuato
     
    Agave temacapulinensis was first collected by Vazquez-Garcia & Chazaro-Basanez in 2010. It was found in the municipalities of Mexticacan and Canadas de Obregon in the Los Altos region of Jalisco, western Mexico. The area is close to the Rio Verde and threatened by the El Zapotillo dam project. It's flowering features place it in the group Ditepalae and there are morphological similarities with A. wocomahi and A. durangensis.
     
    Agave tequilana cv. Limeno ( Kimnach & Trager 1991) :
     
    Agave turneri A new species from northeastern Baja California described in 2011 by R.H.Webb and J.M.Salazar-Ceseña in Brittonia, v. 63 . This solitary species is placed in the group Deserticolae and it's closest relatives appear to be A. moranii and A. desertii v. simplex. It has a very restricted habitat in the Sierra Cucapá and Sierra El Mayor.
     
    Agave valenciana from Jalisco, Mexico; belongs to the Marmoratae group, closely related to A. marmorata. ( Chazaro & Vazquez 2005 )
     
    Agave verdensis ( Hodgson &Salywon 2013 ) from central Arizona. Placed in Ditepalae group. No close relative but some similarities to A. delamateri, A. chrysantha & A. shrevei.
     
    Agave yavapaiensis ( Hodgson & Salywon 2013 ) from central Arizona. Placed in Ditepalae group. No close relative but similarities to A. delamateri, A. chrysantha & A. shrevei.
    .

     A. arizonica

     A.toumeyana ssp. bella x A. palmeri ssp.chrysantha

     A. ajoensis

     A. deserttii ssp. simplex x A. schottii v.schotii

     A. glomeruliflora

     A. lechuguilla x A. gracilipes

     or

     A. lechuguilla x A havardiana

     or

     A. lechuguilla x A. parryi ssp. neomexicana

     A. gracilipes

     A. lechuguilla x A. parryi ssp. neomexicana

     A.leopoldii

     A. filifera x A. schidigera

     A. murpheyi

     A. palmeri x A. angustifolia

     A. nigra

     A. asperrima (scabra) x A. victoriae-reginae

     A. phillipsiana

     A. palmeri x A. americana v. expansa

     A. peacockii

     A. kerchovei x A. marmorata

     A. pumila

     A.lechuguilla x A. victoriae-reginae

     A. romanii

     A. filifera x A. mitis v. albidior (= celsii v. albicans)

     A. saltilloensis

     A.asperrima x A.victoriae-reginae

    A.schottii v. treleasei 

     A. schottii x A.desertii v. simplex

     A. simonii

     A. lechuguilla x A. xylonacantha

     A. victoriae-reginae f. viridis

     A. lechuguilla x A. victoriae-reginae f. fernandi-regis

     

     

      Original Name

       New Name

     Suggested By

     beauleuriana ( Jacobi)

     franzosini

     Breitung

     brauniana (Jacobi)

     obscura

     Ullrich

     elizae ( Berger)

     sisalana

     Ullrich

     elizae ( Berger)

     desmettiana

     Breitung

     erosa ( Berger)

     ? potatorum

     Ullrich

     fenzliana (Jacobi)

     maximiliana

     Breitung

     flaccida ( Jacobi)

     fenzliana ( Jacobi)

     Breitung

     flaccida ( Salm Dyck)

     angustifolia v. rubescens

     Breitung

     friderici ( Berger)

     franzosini

     Breitung

     friderici ( Berger)

     salmiana

     Ullrich

     gilbeyi ( Haage & Schmidt)

     horrida v. gilbeyi

     Breitung

     grandibracteata ( Ross)

     potatorum

     Ullrich

     grandidentata (Jacobi)

     obscura

     Breitung

     henriquesii ( Baker)

     peacockii

     Breitung

     littaeoides ( Pampanini)

     potatorum

     Ullrich

     longisepala ( Todaro)

     ? americana

     Ullrich

     macrantha ( Todaro)

     chiapensis

     Ullrich

     multiflora ( Todaro)

     obscura

     Ullrich

     multiflora ( Todaro)

     polyacantha

     Breitung

     oblongata ( Jacobi)

     celsii

    Breitung / Ullrich

     ottonis ( Jacobi)

     atrovirens

     Breitung

     pampaniana ( Berger)

     shrevei ssp. shrevei

     Ullrich

     paupera ( Berger)

     desmettiana

     Breitung

     paupera ( Berger)

     sisalana

     Ullrich

     pavoliniana ( Pampanini)

     lophantha

     Ullrich

     ragusae ( Terraciano)

     salmiana v. ferox

     Gentry / Ullrich

     schneideriana ( Berger)

     karwinskii

     Ullrich

     sordida ( Berger)

     ? kerchovei

     Ullrich

     troubetskoyana ( Baker)

     marmorata

     Breitung
    Table by Giuseppe Tavormina

    There is an excellent series of articles on agave nomenclature called ' Agaven : What's in a name' by Dr. Peter Kuppen ( in Dutch) in 'Succulenta', Journal of the Belgian / Dutch Cactus Society in vols. 78 (nrs. 4,5,6) and vols. 79 (nrs. 2,3) with a very useful selection of the relevant reference literature.