Volume 5 Number 21 Gymnocalycium Pflanzii

VOLUME 5 NUMBER 21 GYMNOCALYCIUM PFLANZII Collection-H. Middleditch. % GYMNOCALYCIUM SAGLIONIS C oil ect i on - 1. Lavender GYMNOCALYCIUM PFLANZII “Cactus" (Belgium) 3.1.71. GYMNOCALYCIUM PFLANZII (Vaupel) Werd. by M. Broeckhoven (Translated by H. Middleditch from Cactus 3.1 .71 .) Amongst the green coloured 'Gymnos1 with short or insignificant spines, the species which concerns us here holds a special place as much on account of its origins as of its plainly stronger spines. It was named after consul K. Pflanze who discovered it in the neighbourhood of Villa Montes in Bolivia, more exactly on the sandy escarpments at Palo Marcado in the valley of the Rio Pi Icomayo at 50 Km down the river from Vi I la Montes. G. pflanzii is easily recognised by its matt yellowish green appearance and by its rough epidermis which is somewhat reminiscent of that of a peach. If one depends upon the original description, the height reaches 50 mm and the diameter 100 mm, but many reliable writers indicate that, in its habitat, one comes across examples reaching 500 mm in diameter! The old specimens have a little white wool in their growing point; their strong and thick ribs are divided into tubercles of very irregular shape at the base. Whi 1st among the other species of Gymnocalycium, these tubercles become prominent and take on the shape of chins between the areoles, those of this species do not take on this appearance and develop furrows below the areoles in the form of the crescent moon which give a very special appearance to the plant. The areoles are elliptical and reach 10 mm in length by 4 mm breadth and are sometimes 40 mm apart; they are placed in depressions and at first are furnished with long flocculent white felt which disappears with age. The 6-9 radial spines which are distinguishable with difficulty from the central spines, may reach 25 mm in length; they are slightly recurved towards the end, sharp, and as they are stiff, very fierce; they are brownish red at first with blackish tips and very glossy, but on ageing they become wrinkled and of a dirty pinkish-white colour with dark tips. The flowers are white or pale pink and appear in large numbers in the month of June from the young areoles on the crown of the plant. They have a height bnd diameter of about 50 mm. The ovary and the flower tube are olive-green to brownish and furnished with thick brown scales with much paler edges. The stamens are quite peculiar as they remain attached to the flower tube by their base and inserted all the way up the walIs; the highest are quite curved over towards the centre; all are of a purple colour with yellowish anthers and overhanging the pistil which is likewise purple. The seeds are globular, a little like a helmet in shape and do not reach 1 mm in diameter. G . pflanzii is very interesting from the point of view of its classification. If one only takes into consideration its external appearance and its spines, one would be tempted to relate it closely to G. saglionis (of which it could we 11 be on ly a variety?) although the latter is only found further south in the continent: Tucuman and Salta in the north-east of Argentina. However, if one studies the structure of the seeds which more and more are becoming the deciding criterion for many botanists, one would rather relate them to G . oenanthemum. How could we have clearly-defined ideas on this subject since the botanists themselves do not yet appear to be in agreement: C. Backeberg includes it in his sub-group 'Gibbosa', F . Buxbaum in his series ‘Pflanziana' and quite recently Dr. Schutz classified it in his subgenus 'Microsemineum1. This very fine plant is beginning to be found more and more in col lections although one has scant hope of finding it at commercial nurseries since it is indeed not a commercial species; its growth is very slow during its early years and it is necessary to wait a good time before obtaining specimens of marketable size. This is no smalI wonder if one thinks about the fineness of the seeds; how could such a small seed yield a young specimen of rapid growth? Although small, they are however endowed with excel lent potential germination and, when sown in the spring and if the seedlings are well cared for, one may look forward to have graftable seedlings around about the - 59 - month of August (on Echlnopsis hybrid) which wi 11 continue to thrive for a further two months and the following year will have reached a size which allows them to be transferred to a stronger grafting stock such as Tr. spachianus where they reach an acceptable size in a few years. One may, accor ding to one's own inclinations, leave them there to stay or put them on to their own roots but, in that case, it is necessary to provide them with a rich and porous compost. One may overwinter them without heat providing one accepts the slightly washed-out colour during the resting season. It is, in my opinion, a very handsome Gymnocalycium which could not spoil any collection, and I would go so far as to recommend it to those who are not interested in this genus in wishing them every success. Comments on G . pflanzii . from G„J. Swales. "I would agree that there is some simi larity in spines and body form to G . sag I lone, but in fact the seed is quite different. It is one of the smallest seeds in the genus and is quite rightly grouped by Buxbaum with G. zegarrae, lagunillasense, comarapense, marquezii, etc. "The seed of G . oenanthemum bears no resemblance whatsoever to that of G . pflanzii and only a very superficial one to Gymno. saglione. Again, Buxbaum separates G , oenanthemum and G. sag lione into two separate groups, which under the microscope are obviously very different. "As far as the Schutz classification goes, in terms of size the seeds of pflanzii are justifiably placed in the sub-genus Microsemineum. " .......from H. Middleditch "The illustration accompanying the original article in the Belgian cactus journal (reproduced in the accompanying sketch) depicts a plant with a somewhat conical shaped body, slightly taller than broad. The ribs appear to be somewhat higher than on many mature plants in the saglionia group and are divided by very deep cross cuts going down almost to the base of the ribs, so forming tubercles which are fairly tall and which also carry the areole right on the peak of the hump. Both the general body shape and the areole location struck me as being somewhat unusual for this group of Gymnos when 1 first saw the illustration. However, 1 was most interested to see an imported plant of G . marquezii in the collection of R. Sharman which also has the areoles on the peak of the tubercle and is, if anything, rather and more conical shaped than the Belgian plant. Apart from these two specimens, all the other plants of G . pflanzii which I have seen possess broad, flattened ribs with the tubercles separated by shallow grooves. "M y own plant of G . pflanzii was obtained from W. Wessner at Muggersturm on our 1971 Cactus Tour. The rather uncommon appearance of the body probably induced me to select this plant for it is about 3" in diameter but some 5 " in height, columnar, with a low, rounded top. The ribs are very broad and the tubercles very low, rounded, humps. All but the topmost inch or so of the plant is the colour of pale brown earth - possibly because it has been immersed that deep in pale brown earth. Perhaps the summer storms in the Chaco swept increments of earth over the plant each season which it then grew through, or perhaps the plant pulled the growing crown down into the earth during the long winter drought. It is rather like a whodunit - was it buried or did it shrink? One of my other doubtfully-named Gymno seedlings (it has a label, but I doubt the name) appears to be growing we 11 but the top of the plant is now one sand grain in depth below the surface of the soil - having gone there itself, starting from a more orthodox location over the so iI. Presumably this sort of trick was learnt back home. I notice in other col lections several imported Gymnos having a similar coloration near the base and as the concertina-ed tubercles become more turgid and the plant expands, the previously habitat buried portion of the body becomes more evident. - 60 - "The G . pflanzii which I have seen have been either columnar, like the plant on our front cover, or flattened globular with "concertina-ed" tubercles near the base. The diameter has been about 60-70 mm and the height up to 100 mm; nowhere have I seen a plant anywhere approaching 500 mm in diameter - which does not mean to say that they cannot occur that size in habitat. "The flower of G. pflanzii is generally similar to the other species in this group, with the uppermost anthers often being carried a little higher than the stigma lobes, but as the filaments are short and do not lean appreciably inwards towards the centre of the flower, the stigma lobes are usually clearly visible,, I am puzzled by the description of the stamens as 'overhanging the pistil1 as this is not within my experience.

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