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The Thorn in the Side 3°

 

THE THORN IN THE SIDE 3

«Among the books in my library (I’m looking at them now) there are some I will never open again»
Jorge Luis BORGES


- LUCIO, you really got me curious the last time. Tell me!

- The first example I want to give you, dear MARIA, is not so recent and has been partially corrected as to its conclusion only after a long time and by others. It concerns the revision of the genus Epithelantha, published by C. GLASS and R. FOSTER, two Americans well known among the cactophiles at that time, in the remote 1978, in the most prestigious periodical: The Cactus and Succulent Journal of America. These two experts, with their strong and influent point of view expressed in their “Revision of the Genus Epithelantha”, managed to restrain not only any further studies on the relationship between the various entities belonging to this genus, but also, as a consequence, to decrease the interest of the enthusiasts on this subject. In that work, without showing any uncertainty, they stated that there is only a single species made up by six distinct varieties, based on the fact that: ‘.....the distribution of these taxa is so limited, the differences so minor, that .....’. In the same work they accused  C. BACKEBERG, about whom I have already told you, of having described  Epithelantha polycephala '... in a shockingly brief and incomplete way...' since he basically stated that '...the entity in question differs from the genus’ type for its densely clumping growth, with very small stems, often about the thickness of a pencil, .....' omitting the spine count and other measures, and without mentioning flowers, fruits and seeds. At this point, if you would expect to find these data in the revision of the two authors you would end up equally shocked and disappointed: of the six entities treated, for the  varieties micromeris, bokei, unguispina and polycephala just the flowers are briefly mentioned; for micromeris, bokei e greggii just the fruits; and for micromeris and greggii just the seeds. All this gives the impression that the two authors, having seen so many populations in the wild, but perhaps neither having cultivated them from seed, nor pollinated or reproduced them, were moved by an excessive urge to simplify rather than to observe.  Also a question comes to mind: are flowers, fruits and seeds really so important in the internal systematic of the genus Epithelantha?

- Really nice! Now I understand how C. GLASS, in other circumstances, tried to get credit for somebody else’s work, the style is the same! However, I must admit that I have still not clear what the situation of the genus Epithelantha was before the intervention of the two Americans.

- Indeed there was not a ‘single’ situation, as there is not a single situation today, but rather a number of points of view, even if at that time the prevailing one (C. BACKEBERG) was accepting several species: E. micromeris, E. bokei, E. pachyrhiza, E. polycephala. The first species in turn comprised some varieties: var. micromeris, var. densispina, var. greggii, var. rufispina, var. unguispina. E. pachyrhiza too included two varieties: var. pachyrhiza and var. elongata. Nowadays the prevailing point of view, supported by the books of E. F. ANDERSON, The Cactus Family and D. HUNT, The New Cactus Lexicon, is that two species constitute the genus Epithelantha: E. bokei and E. micromeris (made up by five subspecies). Therefore two species, taking note of facts that have been known since a long time, related to the morphology of the plants and the circumstance that the ‘two’ species share some habitats without forming hybrids.

-     Is that all?

-   To start with, we see that there is a trend, a fashion perhaps, to put different entities together at any cost, even at the risk of being brutally contradicted by the facts. Would not it have been better to have made some more observations before coming to a close with the revision?  And why accusing C. BACKEBERG of having made some faults if the same faults were later repeated by C. GLASS and R. FOSTER too?

-     What you say is right, LUCIO, but it still seems too little to me!

-    In this case I can add more! You must know that there are locations in the wild where E. greggii and E. pachyrhiza live together at a very short distance, no more than thirty meters, without producing hybrids (i.e. intermediate forms); thus, each of the entities treated as subspecies of micromeris is well characterised, both in the morphology of the old and the young specimens and in the micromorphology of the spines, and there are other, very constant differences; this, however, only  if  E. rufispina and E. densispina, which probably are two particular ecotypes connected to the reddish sandstone the former and to the white crystalline limestone the latter, are also included in E. greggii. Finally, you must know that I took the trouble to try crossing all the remaining micromeris ‘subspecies’ in order to understand if they were at least genetically compatible. I should start by pointing out that I have not tried all the possible combinations of the five different subspecies, but only the crosses E. micromeris × greggii, E. micromeris × polycephala and E. micromeris × unguispina; furthermore, the hybridisation attempts have been few (I will explain you why later on) and involving just three or four flowers each try. I can tell you that I have obtained fruits from E. micromeris × greggii and from E. micromeris × unguispina only, which contained each only 2-3 seeds, while you normally can get 6-7 seeds per fruit, with the exception of E. pachyrhiza from Hipolito where you can get up to 15 seeds per fruit. Furthermore, the seeds of E. micromeris × greggii were reddish-yellow, miscarriages, none of which germinated. Only from E. micromeris x unguispina, I have been able to get two small and weak seedlings. You will understand that this small amount of data does not allow me to draw any certain conclusion, but at least I can see the indication that it seems rather difficult to treat them as a single species.

-     My dear, I have obtained hybrids between E. greggii and micromeris many times! Are you sure of what you are saying?

-     Yes, I think so! Your greggii SB 321, obtained from seed sold by an American nursery, is just another of the many forms of micromeris available. I think that much of the confusion surrounding the knowledge about the genus Epithelantha is due to botanical material that has not been properly classified and let alone associated to correct locality data; unfortunately, even all the Italian nurseries are spreading these errors.

-    But why so few attempts at hybridisation?

-    First of all, I have not tried pollinating E. micromeris with pollen from other entities since it is self-fertile and regularly selfs itself, contrary to the other forms, so I would have always ended up with just seeds of micromeris. On the other hand, the flowers are so small that I have not been able to eliminate the stamens without damaging the stigma. So I have limited myself to use just the pollen of micromeris. It should also been observed that, when the very small perianth of a flower dries out, it soon gets removed by the growth of the spines on the apex of the plant, and since the fruit is deeply hidden between the spines around the apex, it is impossible to link it with certainty to the pollinating operation due to the abundant bloom, ten-twenty flowers per head within a diameter of two-three centimetres! On top of that, the fruit appears after a period that varies from one to six-eight months after the pollination, and this makes even more difficult the task of collecting data. Finally, it is not unusual that the fruit may be expelled by the growth of the plant, even after one year from the pollination, looking like a minute, grey sack, showing up unexpectedly among the spines.

-      LUCIO, it is possible that exactly these difficulties have prevented GLASS and FOSTER to make these checks!

-      Maybe so, but this does not absolutely justify their position. You see, they have drawn an illegitimate conclusion about E. bokei and most probably about the others; in any case, without sufficient facts on which to base their opinion, they should neither revise nor recombine bokei and also polycephala. And here we want to consider prescribed similar errors made earlier by other authors that have previously worked on the genus Epithelantha. Please, take also into account that this revision has effectively restrained the studies for about thirty years.

-      I am starting to understand, was it not an isolated case?

-      Dear MARIA, if this were an isolated case, it would have been simply treated like an unfortunate event, corrected after a long time, and part of the normal debate between lumpers and splitters. Next time I will show you that there are indeed other examples, similar in the method and in the conclusions, that  lead to think that in normal dialectic, one of the parts willingly carried out these abuses!