U vindt dit artikel in de Nederlandse taal in Succulenta No.5 van 2006

Agave obscura schiede

Agaves in flower 2, article from the Dutch society Succulenta 2006 no.5

Wim Alsemgeest  Jos van Roosbroeck and Theo van ‘t Walderveen

Agave obscura 7km East of Las Vigas Veracruz

In 2005 an agave obscura from Wim’s collection flowered. The plant was seen to be preparing itself for two years for this event.  It was possible to observe gradual changes in the centre of the plant,  the leaves becoming smaller as did the teeth, some of which vanished completely. Once the actual flowering process started offsets were produced both at the base of and centrally within the plant.  The flower-stalk grew to a length of 2,5 metres. Only three fruit capsules developed and no bulbils (small plants on the flower stalk) were produced.
Also in 2005 one of Jos’s plants of this species underwent this process of flowering. This was a much bigger plant and the initial flower stalk was actually produced from one of the offsets rather than the main plant. Unlike Wim’s plant this one ultimately produced an abundance of bulbils and seeds.  Jos wanted to  test the hardiness of this plant as the temperature in his greenhouse had dropped the following winter to minus 3 degrees Celsius for three consecutive days. The plant remained undamaged at that temperature and then, in 2006,  the plant was in full flower, this time the inflorescence coming from the centre of the plant.

In the meantime, in the spring of 2006, Wim travelled to Mexico and visited the habitat  of this species,  Las Vigas in the state of Veracruz.  There he found the plants growing on  lava fields at an altitude  of 2385 metres. On that day at the beginning of February there was  a nice comfortable temperature of  20 degrees Celsius . One day earlier and not too far away there was no nice sunshine and the temperature was only 3 degrees. Time for winter clothes!
In cultivation this species gives few problems at a lower temperature.

There were fir trees growing on the lava fields and that gave the agaves some protection from the sun. It was quite an experience to see the plants growing in the shade of the trees. Where the  tree growth ended so did that of the agaves . The plants seen were wet from earlier rainfall.
We saw a lot of seeds in the middles of plants and so concluded  that the most seeds were falling right into the plants themselves and then were washed to the ground by rainfall.

In an edition of the magazine “ Kaktusblute” from April 1992,  Bernd Ullrich wrote about his extensive research  into this species and about  agave horrida ssp.perotensis.
We found this research to be very interesting but also very complex and  we had to read the article about  6 times before we could fully appreciate the clear meaning of the author’s work.

It appears that  this species was discovered in 1829 and than transported to Europe.

Agave horrida ssp.perotensis 16 km North East of Zacatepec Puebla.

If we have fully understood Ullrich’s work  then this is the story:

In 1829/1830 the horticultural collector  Schiede found a new  agave in the  malpais or lava fields above La Jolla,  a small village between  Jalapa and Las Vigas in Veracruz.
Because of the dark red flowers of this  plant he gave it the name agave obscura.
Alas Scheide’s plants failed to establish themselves in European gardens and collections and so this name was subsequently confined to the literature.
In 1865 Jacobi  did not recognise this name and used the name  agave xalapensis ( Roezl ex Jacobi ) for this  species .
William Trelease,  director of the Henry Shaw Botanical Gardens in St. Louis,  Missouri and  noted  authority on  yuccas and agaves, visited this part of  Veracruz in February 1905 by train.. He concluded  in 1920, that the agave growing in the lava fields of El Limon, about  30km west of La Jolla, wrong as  Schiede’s agave obscura. That was wrong because, this plant was an form of A. horrida (Lemaire ex Jacobi) Charazo 1981.In 1981 Chazaro made the same trip as Schiede and Trelease and discovered that agave obscura and agave xalapensis were one and the same plant and that the name obscura had   priority over  xalapensis by some 35 years. The plant named by   Trelease as agave obscura is seen   by Chazaro  as agave horrida ( Lemaire ex Jacobi ).
Gentry in 1982 appeared unaware of this article by  Chazaro and so mistakenly considered this xalapensis  as  agave polyacantha var. xalapensis. He didn’t know at that time  that there was also another species in the same territory. He noted  that agave obscura is difficult to separate from agave horrida ,which actually grows in the mountains and volcanic rocks  of Morelos . It would now appear that he was not describing the true agave obscura but a different species , later described by Bernd Ullrich as agave horrida ssp perotensis.
Ullrich was in agreement with  Chazaro. The agave which Chazaro identified   as  agave horrida ( Lemaire ex Jacobi ) was subsequently described by Ullrich  as agave horrida ssp.perotensis. because hi see som differents between A. horrida (lemaire ex Jacobi)  and A. horrida ssp.perotensis
The  agave polyacantha var. xalapensis shown  in Gentry  on page 231 is now regarded as the neotype for agave obscura. Neotype means that the picture illustrates the originally  described plant. The plant named as agave polyacantha on  page 229 is the of same variety, also agave obscura.  These pictures show a striking variation in size of the teeth of the different plants.

On page 17 of August Breitung’s book on agaves from 1968  is a picture of an agave  horrida labelled  as agave obscura . On various websites you can also see pictures mistakenly labelled as agave obscura but showing plants from sites much further  south than the true  obscura. The site of agave obscura is between  Las Virgas and La Jolla in the state of  Veracruz.
Agave horrida ssp. perotensis grows some 50 km further south, between  Perote in the state of Veracruz and  Zacatepec just over the border with the state  of Puebla..

Thus we propose that the names in Gentry’s book  be altered.  Perhaps later  we shall be able to produce  an article about agave horrida ssp. perotensis, a subspecies of agave horrida ( Lemaire ex Jacobi ) .

1. Agave obscura is an old, well known plant, imported long time ago and found in many collections, often incorrectly named as  agave  xalapensis or agave  polyacantha var. xalapensis. This error , unknown at the time of writing,  also applies to the  monumental work on agaves  by Gentry.
The only site of this species ,as far as is known, is in the state  Veracruz,  4 miles east of Las Vigas, along the way to Xalapa on highway nr. 140.

2. Agave horrida ssp. perotensis  is a subspecies  of agave horrida often  incorrectly named as agave obscura. This applies to the works of  Gentry and Breitung.
The site of this species is on the border of the states of Puebla and  Veracruz ,  4 or  5 miles  north of El Limon. We found the plants about 16 km north east of Zacatepec on the border of the states of Veracruz and Puebla.
Agave horrida itself is very common in the state of Morelos ,between  Cuernavaca and  Mexico City, often simply growing alongside the highway. But in 2006  we also found a different form east of Asuncion nochixtlan in Oaxaca, much more South in Mexico. It is possible that this is in fact a form of agave ghiesbreghtii??.Take a look at the picture here under:

Agave horrida growing much more south by Asuncion Nochixtlan Oaxaca.

Agave attenuata var. subdenudata Hort. Ex Trelease
Agave caribae Verschaffelt
Agave chloracantha Salm-Dyck (1859)
Agave densiflora Hooker (1857)
Agave  densiflora var. angustifolia Hort ex Besaucele
Agave densiflora var. folijs striates aureis Hort ex Besaucele
Agave engelmannii trelease (1892)
Agave flaccifolia Berger (1915)
Agave hookeri Hort ex Besaucele
Agave lamprochlora Jacobi
Agave micracantha Baker
Agave muilmannii Jacobi (1870)
Agave myriacantha Hort ex Besaucele
Agave polyacantha Jacobi
Agave polyacantha var. densiflora (Hooker) Terracciano
Agave polyacantha var. xalapensis (Roezl ex Jacobi) Gentry (1982)
Agave uncinata Jacobi (1865)
Agave xalapensis Roezl ex jacobi (1865)

Basanez.M.de J.C. (1981) : Biotica Vol.6 Numero 4. Nota sobre la tipificacion de agave obscura Schiede Y su confusion con Agave Xalapensis Roezl.
Baker.J.G. (1888) Handbook of the amaryllideae pag.168
Berger, A. (1915) : Die Agaven – Beiträge zu einer Monographie, - Gustav  Fischer Verlag Stuttgart, New York.
Breitung,A.J. (1968) . The Agaves . The Cactus  and Succulent. Journal Yearbook. Abby Garden Press.
Garcia-Mendoza, A.(2002): Distribution of Agave (Agavaceae) in Mexico. C&S.J.(US) 74 (4):178.
Gentry, H.S. (1982) Agaves of the continental North America – The University of Arizona Press, Tucson.
Heller Thomas (2003) Agaven Natur und Tier Verlag GmbH Munster
Irish, M.& G. Irish (2000) : Agaves and related Plants – A Gardners Guide – Timber Press Portland Oregon.
I.P.N.I. The International Plant Names Index. Internet: http://www.ipni.org
Korevaar, L.C. et al. (1983) Wat betekend die naam. Botanisch Latijn toegankelijk gemaakt. Succulenta.
Thiede, J. (2001): Agavaceae – In Eggli, U. :Sukkulentenlexicon  Band 1, Einkeimblättrige Pflanzen. (Monocoltyledonen).- Verlag Eugen Ulmer, Stuttgart.
Ullrich, B. Agavensystematiek Fur dass I.O.S.- Lexicon (1. Vorschlag) 3/1991
Ullrich, B. Agave obscura SCHIEDE und Agave horrida LEMAIRE ex JACOBI ssp. Perotensis ULLRICH,ssp.nov. Kaktusblute 9.april 1992 pag.12-19.

Thanks to Jan Kolendo for the help with the translation from Dutch to the English language for this article.

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