Taxonomic history, comparative morphology, and variation in Astrophytum myriostigma and its subspecies tulense (Cactaceae)


  • Richard R. Montanucci Department of Biological Sciences, Clemson University
  • Klaus-Peter Kleszewski



Astrophytum myriostigma subsp. myriostigma and subsp. tulense are distinguished by both vegetative and reproductive characters. The stem of the nominotypical subspecies is broad and depressed becoming broadly cylindrical in age, reaching a known maximum height of ca. 52 cm. In subsp. tulense, the stem is relatively slen-der and columnar and can reach a maximum height of ca. 90 cm. Both taxa show variation in the angle and profile of the ribs. In the nominotypical subspecies, the ribs are usually obtuse with a rounded or angular profile, or moderately acute with an angular profile. In subsp. tulense, the ribs are typically moderately to very acute with an angular profile. There are exceptions to these generalities. Both taxa have a modal number of five ribs, and both have the tendency to insert additional ribs with age, although the tendency seems more pronounced in subsp. tulense.

The flower of the nominotypical subspecies differs from that of subsp. tulense in having a significantly larger mean perianth diameter (P <= 0.01), a significantly higher mean number of stigma lobes (P <= 0.05), and more tepal rows (3–5 vs. 1–3). The color of the tepals is pale yellow to whitish yellow in subsp. tulense, but brighter yellow or golden yellow in the nominotypical subspecies. The seeds of the nominotypical subspecies are significantly larger (P <= 0.01) than the seeds of subsp. tulense.

Morphological variation was studied in nine populations of the subsp. myriostigma and six populations of the subsp. tulense. The nominotypical subspecies displays rib angle and rib profile differences among individual plants within a population. Plants with a depressed stem and obtuse, rounded ribs are predominant at some localities. At other localities, plants with more moderately acute, angular ribs are predominant, or at least common. Populations of subsp. tulense show individual variation in stem morphology. The stem varies from attenuated (tapered) to non-attenuated and from relatively slender (diameter ca. 20% of height) to relatively broad (diameter ca. 77% of height).

The plants from near Mama León and adjacent localities in Tamaulipas, have very robust stems and are the least typical of the columnar subspecies. The rela-tionships of this population to other columnar populations warrant further study. The population near Las Tablas, San Luis Potosí, shows considerable variation in the stem and rib morphology. Some plants resemble the nominotypical subspecies whereas others are similar morphologically to subsp. tulense. The perianth diameter is intermediate between those of the two subspecies. The evidence suggests that this is an area of past or ongoing hybridization between the two taxa; the question of hybridization warrants further investigation.

Attenuated and non-attenuated stems are the result of differential rates of vertical and lateral growth due to cellular activity in the apical and lateral meristems, respectively. The attenuated (tapered) stem is produced by a gradually increasing lateral growth rate which remains slower than the vertical rate. A non-attenuated stem is produced by the lateral growth rate exceeding the vertical rate early in development, then stabilizing at some point and not surpassing the vertical rate.


Backeberg, C. 1961. Die Cactaceae. Vol. 5. Gustav Fischer Verlag, Jena, Germany.
Du Rietz, G.E. 1930. The fundamental units of biological taxonomy. Svensk Bot. Tidskr. 24:333–428.
Eggli, U. 1985. Backeberg’s invalid cactus names. Bradleya 3:97–102.
Ehrenberg, C.A. 1847. In: Schlechtendal, D.F.L. 1847. Beitrag zur Geschichte einiger mexicanischer Cacteen. Linnaea 19(3):337–368.
Galeotti, H.G. 1939. In: Scheidweiler, M.J. 1839. Cereus callicoche Galeotti. Bull. Acad. Roy. Sci. Belles-lettres Bruxelles 6:88.
Gibson, A.C. & P.S. Nobel. 1986. The cactus primer. Harvard University Press, Cambridge, Massachusetts, U.S.A.
Hirscht, K. 1895a. Aus der Gesellschaft der Kakteenfreunde. Monatsschr. Kakteenk. 5(7):111.
Hirscht, K. 1895b. Aus der Gesellschaft der Kakteenfreunde. Monatsschr. Kakteenk. 5(8):127.
Hoock, H. 1990. The Myriostigmas of San Antonio. Brit. Cactus Succ. J. 8(3):68–73.
Hoock, H. 1993. Entdeckt, verloren, wiedergefunden: Astrophytum myriostigma Lemaire bei der Mine von San Rafael, San Luis Potosi. Kakteen And. Sukk. 44(10):212–215.
Hoock, H. 2008. Astrophytum Lem. (Cactaceae). Schoendruck–media e. K., Landshut, Germany.
Kayser, K. 1932. Astrophytum myriostigma subspecies tulense. Kakteen-Freund 1(6):57–59.
Kleszewski, K. P. 2001. Astrophytum myriostigma Lemaire entlang der Carretera Rural von Las Tablas in Richtung Norden. Kaktusblüte. Pp. 21–24.
Kleszewski, K. P. & H. Hoock. 2007. Wuchsformen von Astrophytum myriostigma subsp. tulense Kayser. Kakteen And. Sukk. 58(10):267–272.
Lawrence, G. 1841. In: Loudon, J.C. 1841. Catalogue of the cacti in the collection of the Rev. Theodore Williams, at Hendon Vicarage, Middlesex. Gard. Mag. 17:313–321.
Lemaire, C. 1839. Cactacearum genera nova species que novae et omnium in Horto Monvillano cultarum. Pp. 3–6
Lux, A. & R. Stanik. 1985. Formenreichtum bei Astrophytum myriostigma Lemaire. Kakteen And. Sukk. 36(1):17–20.
Megata, M. 1944. An account of the genus Astrophytum Lemaire. Mem. Coll. Agric. Kyoto Imp. Univ. 56:1–62, 10 plates.
Möller, H. 1927. Beobachtungen an Astrophyten. Z. Sukkulentenk. 3(3):52–55.
Montanucci, R.R. & K.P. Kleszewski. 2019. Nomenclature and redescription of the Jaumave Valley (Mexico) populations of Astrophytum myriostigma (Cactaceae). J. Bot. Res. Inst. Texas 13(1):63–69.
Montanucci, R.R. & KP. Kleszewski. 2020. A taxonomic evaluation of Astrophytum myriostigma var. nudum (Cactaceae). J. Bot. Res. Inst. Texas 14(2):255–264.
Okumura, Y. 1933. Classification of Astrophytum. Syaboten-no-Kenkyu 4:174–175, 195–201, 215–216. (in Nipp.)
Powell, A.M. & J.F. Weedin. 2004. Cacti of the Trans–Pecos & adjacent areas. Texas Tech University Press, Lubbock, Texas, U.S.A.
Sadovský, O. & B. Schütz. 1979. Die Gattung Astrophytum. Arten. Hybriden. Kultur. Flora–Verlag, Titisee–Neustadt, Germany
Schätzle, P. 1988. Astrophytum myriostigma Lemaire subspec. tulense Kayser Ein Versuch zur Klärung eines neuen Fundes. Kakteen And. Sukk. 39(11):254–256.
Schätzle, P. 1990. Astrophytum myriostigma Lemaire var. columnare (K. Schumann) Tsuda Varietät oder Form? Kakteen And. Sukk. 41(5):94–97.
Schätzle, P. 1992. Zwei Astrophyten aus dem mexikanischen Bundesstaat San Luis Potosi. Kakteen And. Sukk. 43(7):150–154.
Schumann, K. 1898. Gesamtbeschreibung der Kakteen. J. Neumann, Neudamm, Germany.
Sinnott, E.W. 1960. Plant morphogenesis. McGraw–Hill Book Co., Inc. New York, New York, U.S.A.
Stace, C. 1989. Plant taxonomy and biosystematics. 2nd ed. Edward Arnold, London, UK.
Tsuda, M. 1934. Cultivation of cacti. I. Astrophytum. Shaboten 1:7–14.
Viereck, H.W. 1939. Astrophyten, wie sie der sammler in den Heimatgebieten sieht. Beitr. Sukkulentenk. Sukkulentenpflege 1:4–8.



How to Cite

Montanucci, R. R. ., & Kleszewski, K.-P. . (2021). Taxonomic history, comparative morphology, and variation in Astrophytum myriostigma and its subspecies tulense (Cactaceae). Journal of the Botanical Research Institute of Texas, 15(2), 327–341.