Agave striata and Agave stricta are similar looking plants that both belong to the group Striatae. Agave striata has a wide ranging distribution and can be found in much of the Chihuahuan Desert Region mostly from central Coahuila and Nuevo Leon south into northern Zacatecas, southwestern Tamaulipas, much of San Luis Potosi, and into Hidalgo. It was first described by Zuccarini in 1833. In 1875 Engelmann described Agave falcata with no mention of how it differed from Agave striata. In 1982 Gentry reduced Agave falcata to subspecies status under Agave striata stating “Agave falcata is too closely related to A. striata for me to maintain it as a species.” This was a very good move on his part as the distinction between the two is quite tenuous. Gentry separates them in his key by vegetative characteristics:
Rosettes with numerous leaves; leaves 1 cm wide or less – key out to A. striata ssp. striata
Rosettes with relatively few leaves; leaves more than 1 cm wide, thickly keeled , frequently falcate – key out to A. striata var. falcata
Although the taxon is based on the falcate (curved) nature of the leaves, this trait can be seen in Agave striata ssp. striata as well as in A. stricta and, by itself, is not a valid characteristic on which to base a species, or even a subspecies.Even when combined with the wider leaves having the prominent keel, the case is only marginally stronger for variety status.
Just where does Agave stricta fit in with Agave striata?
Salm-Dyck originally described A. stricta in 1859 with Baker (1888) changing it to Agave striata var. stricta in his Handbook of Amaryllideae. In 1982, Gentry used the flower measurements to elevate A. stricta back to species status.
|Species||Ovary length||Tube length||Tepal length|
|Agave striata||12-15 mm||14-20 mm||5-7 mm|
|Agave stricta||8-11 mm||8-10 mm||8-10 mm|
As seen in the table above, the ovary and tube length are 2-3 times as long as the tepals for Agave striata while they are all virtually the same length for Agave stricta. That would appear to be a taxonomically significant difference, thereby precluding the lumping of A. stricta in with A. striata.
However, in 1990, Bernd Ullrich reduced Agave stricta to subspecies status under A. striata. My German is a bit rusty, and I could not find any German Shepherds to read it, so through a rough translation with the help of Google Translate, I found that he does not deem the tube/tepal length ratios to be taxonomically significant, but rather used the vegetative similarities as the basis for relegating A. stricta to subspecies status under A. striata. He compared the A. striata/A. stricta relationship to those of the subspecies within the A. asperrima complex and also the subspecies within the A. cerulata complex. I disagree with those comparisons since the floral measurements of the subspecies of the Agave asperrima complex are so similar as are the floral measurements of the subspecies of the Agave cerulata complex.
Dr. Joachim Thiede, In the Agave section of the Illustrated Handbook of Succulent Plants: Monocotyledons, edited by Dr. Urs Eggli, kept Agave striata and Agave stricta as distinct species, emphasizing the floral differences as do most other botanists.
On my most recent trip to east-central Mexico with Brian Kemble of Ruth Bancroft Gardens in Walnut Creek, CA, and Jeff Chemnick, cycad expert and tour guide extraordinaire, at about 20 KM north of Ixmiquilpan, Hidalgo we came upon a population of Agave that looked very much like Agave stricta, but would be way out of its range. The plants were in flower (see below), but none of us could remember which species was supposed to have the longer tube and shorter tepals. A call to Tim Gregory later that evening and his response was “Agave stricta only grows around Tehuacan!”. We just had to wait until we could look at Gentry’s book to confirm whether it was Agave striata or Agave stricta with the long tube, and finally it was confirmed that the plants we saw were A. striata.
Compare the plants in the picture above to those in the pictures below and note the vegetative similarities.
Agave striata has many color forms and sometimes the rosette is smaller and sometimes larger. The following pictures reflect that huge range of variation.
Martin and Julia at agavaceae.com have some valuable information and wonderful photos on their site.
Click here to go to the koehres-kaktus photo gallery which has some nice shots of various Agave striata forms, although they are mis-identified as Agave stricta.
Don’t forget to visit the store and purchase your very own Agave striata!!
As always, thanks for checking out the blog and I hope you enjoyed the adventure. Until next time.