The first instalment of this article appeared in TSG September 2008 Vol. 14 No. 3 (see part 1) and the second in TSG June 2009, Vol. 15, No. 2 (see part 2). In the third and final part of this review I will conclude the discussion of the names presently associated with Cumulopuntia sphaerica and suggest a tentative new classification with five recognised species. One new combination in Cumulopuntia is required and published here.
Opuntia ignota Britton & Rose
Britton and Rose described this taxon in The Cactaceae Vol 1 (1919: 99) and on the same page as Opuntia campestris. They were both collected by Dr Rose on August 23, 1914 at the railroad station at Pampa de Arrieros, on the Arequipa/Puno railway. The description is brief but concise and included here in full:
“Low, much branched, spreading; joints small, narrow, 2 to 3cm long, more or less purplish; leaves minute, often purplish; spines 2 to 7 from an areole, brownish, acicular, the longest ones 4 to 5cm long; glochids, when present, yellow; areoles large, full of grayish wool; flowers and fruit not seen.”
Britton and Rose continue “Plants grown in greenhouses are dark green and develop few spines or none. This plant grows in the same region as O. campestris, but is quite different from it.”
Since its discovery and description over 90 years ago there is no evidence anyone other than Rose had found the true Opuntia ignota in the field, possibly due to the only access being by train until the recent construction of the new Arequipa/Puno highway. Therefore the name ignota is very appropriate as it derives from the Latin to overlook or not recognise.
On the hills above Pampa de Arrieros I found a large number of Cumulopuntia corotilla and mixed into the population were a handful of plants which looked significantly different and which I couldn't identify. On my return home I checked the literature and it became clear I had encountered Opuntia ignota. The photographs included here are possibly the first published of this species (Figs. 1 to 4).
Fig. 1. Cumulopuntia ignota PH710.05 Pampa de Arrieros, Arequipa, 3820m (Type locality). Plant in active growth in rainy season.
Fig. 2. Cumulopuntia ignota PH783.01 3790m. In same location as Fig. 1 but in the dry season.
Fig. 3. Cumulopuntia ignota PH783.01 segment (25mm long excluding spines) and fruit.
Fig. 4. Cumulopuntia ignota PH783.01 showing tapering root.
The plant forms low clumps, branching differently from Cumulopuntia sphaerica, with new heads forming at ground level and not forming chains of stems upwards. The small ovoid heads, 30mm by 15mm are purple coloured with straight radiating spines up to 8 in number and 50mm long. The spination is reminiscent of Cumulopuntia leucophaea (see later in this article, Fig. 10). New heads are a dark green with weak or absent spination (Fig. 1). Interestingly neither flowers nor fruits where seen in February 2008, just as Rose failed to encounter them in August 1914.
During a return visit to Pampa de Arrieros in 2009 I paid more careful attention to this plant. A healthy population with tens of specimens was found in a small rocky gully. Reinforcing its reputation for shy flowering only a couple of fruits were found which were small, up to 15mm in diameter and reddish in colour. Areoles were only present around the rim and contained up to 6 strong spines to 20mm long. A maximum of 3 seeds was found in any one fruit.
I also found this plant a few kilometres down the road growing in association with Cumulopuntia leucophaea. At each of the two localities I examined the roots of a plant and found them both to form a slightly thickened tapering rootstock (Fig. 3). I found this to be identical to the roots on a small seedling of Cumulopuntia boliviana ssp. ignescens (Fig. 5). It is clear this species is not related to Cumulopuntia sphaerica but has characteristics closer to Cumulopuntia boliviana (Fig. 6). These include the way the plants branch, forming low mounds, and the tapering root. It grows in close association with Cumulopuntia boliviana ssp. ignescens although they are distinct with no intermediates or hybrids observed.
Fig. 5. Cumulopuntia boliviana ssp. ignescens PH783.04 showing the same root structure as Cumulopuntia ignota PH 783.01 (see Fig. 4).
Fig. 6. Cumulopuntia boliviana ssp. ignescens PH783.04 growing sympatrically with Cumulopuntia ignota PH783.01.
Cumulopuntia zehnderi (Rauh & Backeberg) Ritter
Rauh and Backeberg described this plant as Tephrocactus zehnderi in 1957 from material collected below Nevada Sara Sara, near the settlement of Incuyo at 3500m. Ritter made the combination into Cumulopuntia in 1981. The description calls for a cushion forming plant with globose tuberculate segments of 3-4cm, sometimes more elongate. Areoles 20-25 per segment, large to 1cm or more, with prominent abundant wool. Spines 3-8(-10) on many areoles, unequal to 3cm, spreading or recurved. Flowers 3cm and yellow. Rauh reports it grows in association with his Tephrocactus fulvicomus which is a form of Cumulopuntia boliviana.
There is nothing in the description which immediately identifies this as a distinct taxon within the Cumulopuntia sphaerica complex but on encountering the plant at a number of localities (where it is morphologically consistent) it is clearly different from C. sphaerica. The plants form clumps, no more then 3 or 4 segments high of slightly elongating heads with large, angled tubercles which are particularly pronounced on dehydrated plants. The shape and form of the segments is very distinct from C. sphaerica. The areoles are very large with white wool (Fig.7). The spination is also very distinctive with spreading recurved spines. In November 2005, inland from Chala, we found plants in flower which were consistently yellow but fade to light orange on wilting (Fig.8). The fruits have similar spines and large white areoles but they are restricted to the uppermost part around the rim. The lower part of the fruit is naked and devoid of areoles. A section of a ripening fruit is shown in Fig.9. The thick wall of the fruit and dry cavity, both characteristics of the genus Cumulopuntia, are clearly shown. The seeds have a thin central band around the centre, known as a funicular girdle. Subsequently, I failed to germinate any of the seeds although they may not have been ripe when collected.
Fig. 7. Cumulopuntia zehnderi PH751.01 Ayacucho, type locality.
Fig. 8. Cumulopuntia zehnderi (Rauh & Backeberg) Ritter PH590.02 inland of Chala on road to Malco, Ayacucho, Peru.
Fig. 9. Cumulopuntia zehnderi PH590.02 sectioned fruit.
Cumulopuntia alboareolata (Ritter) Ritter
Ritter described Tephrocactus alboareolatus in 1963 and subsequently moved it into Cumulopuntia in 1981. The type locality is given as east of Quichaca at 3000m, in the department of Arequipa, which is approximately midway between Chala on the coast and Incuyo (the type locality of C. zehnderi, further inland). Ritter's description calls for a loose low clump with segments 5-10cm long and 3-5cm thick, greyish green. The large areoles, 5-7mm in diameter sit at the top of a tubercle. The spines, 3-8 in number are 2.5 to 8cm long. Flowers are yellow fading to red. Ritter illustrates 2 plants (1981, Abb 1099/1100) and although the one in habitat is a rather poor photo, the large white areoles are clearly visible. The other photo is of a weakly spined cultivated plant. However it is clear Cumulopuntia alboareolata is a redescription of Cumulopuntia zehnderi and it should be sunk into synonymy beneath it. The name Cumulopuntia zehnderi takes priority due to the earlier publication date.
On the road from Caravelí and Cahuacho, to the east of Quicacha, I found Cumulopuntia zehnderi and Cumulopuntia sphaerica (small segmented form) growing together, further confirming they are two distinct species. The distribution of Cumulopuntia zehnderi is restricted to the triangle between Chala, Incuyo and Cahuacho, where I have observed plants at altitudes between 2580m and 3700m.
We are still lacking important information on a number of taxa and further study is required particularly on flowering and fruiting material. Also in the light of significant differences in root structure this under-appreciated characteristic in this group is worthy of further investigation. However we can make progress in a number of areas. It is clear that there is more than one species involved in Cumulopuntia sphaerica as defined in the latest publication Hunt (2006). If we only consider a species level classification and ignore lower ranks, Cumulopuntia sphaerica can be circumscribed by non-tuberculate plants with large segments and yellow flowers from the western sides of the Andes. The distribution is fragmented into a number of populations predominantly at lower altitudes (below 3000m). The type form occupies a relatively small area around the city of Arequipa and there are a number of small isolated populations (C. tumida, C. crassicylindrica and C. kuehnrichiana) which perhaps deserve subspecific status. They all retain the large spherical segments but have distinctive spination.
I consider the small growing form a good species (although clearly related to C. sphaerica) due to its consistent spination and dwarf segment size over a wide geographical range which distinguishes it from Cumulopuntia sphaerica. It possibly evolved as a fixed juvenile form with a number of characters suited to rapid dispersal; small sized, easily detached and rapidly rooting stems. At Arequipa it grows with Cumulopuntia sphaerica without any observed hybrids. Fig. 10 shows a single segment of C. sphaerica with a small plant of O. leucophaea from that locality. Note the fibrous roots on the later. I also believe C. sphaerica is fibrous rooted but I have not examined a plant in habitat. I also include here the coastal plants (Cumulopuntia unguispina) and the higher altitude plants (Opuntia leucophaea). Backeberg used the name Tephrocactus dimorphus for this form but it is uncertain if this name is correctly applied. The description does not match the plant completely and no type specimen exists. Unfortunately no precise locality is recorded either. Therefore I would prefer to use the name Opuntia leucophaea because the description, although brief, matches well. There is a type plant (SGO 052672) and a precise locality recorded. Cumulopuntia unguispina is a later synonym.
Fig. 10. Cumulopuntia sphaerica PH781.01 (left) & Cumulopuntia leucophaea PH781.02 (right) near Mina Cerro Verde, Arequipa, 2640m.
Both Cumulopuntia sphaerica (in all its forms) and Opuntia leucophaea share a characteristic blue waxy coating on the epidermis which evolves as the segments mature after the initial rapid growth phase. This character is not shared by any other of the taxa discussed here.
Where Cumulopuntia sphaerica meets plants from the Cumulopuntia boliviana complex from the west, in a band encompassing an area inland from Nazca in the north to Laguna Titicaca in the south, generally between 3000-4000m, a number of taxa have been described with varying degrees of tuberculate bodies and glochids. At this time I am happy to retain Cumulopuntia zehnderi and Cumulopuntia corotilla as good species. Further work is required in the Nazca valley to determine the relationships of Cumulopuntia galerasensis, Tephrocactus bicolor and Cumulopuntia sp. (Puquio).
Finally I am retaining Cumulopuntia ignota as defined by Britton and Rose as a good species. It is a distinct little plant, with affinities to Cumulopuntia boliviana, which deserves to be studied in more detail, especially flowering material. It is interesting to note we now have two further examples of sympatric sister species, one a dwarf form of the other; Cumulopuntia sphaerica/leucophaea (at Arequipa) and Cumulopuntia ignescens/ignota (at Pampa de Arrieros). This twin species concept also occurs in other Opuntioid genera. I know of two further examples: Tephrocactus geometricus/bonnieae and Maihueniopsis glomerata/conoidea.
This study has been primarily undertaken with habitat observations of vegetative characteristics as unfortunately flowering material was not seen for a number of taxa. Ideally further work is required to look at fertile material, particular flowers and seeds. DNA analysis of correctly identified material of the overlooked taxa would also be beneficial.
Tentative species level classification with synonyms
Old names of uncertain application have been left in synonymy under Cumulopuntia sphaerica.
1) Cumulopuntia sphaerica (Förster) E.F.Anderson, Cact. Succ. J. (US) 71(6): 324. (1999).
Cumulopuntia crassicylindrica (Rauh & Backeberg.) Ritter, Kakteen in Südamerika 4: 1254. (1981)
Cumulopuntia kuehnrichiana (Werdermann & Backeberg) Ritter, Kakteen Südamerika 4: 1253 (1981)
Cumulopuntia multiareolata (Ritter) Ritter, Kakteen in Südamerika 4: 1252 (1981)
Cumulopuntia rauppiana (K.Schumann) Ritter, Kakteen in Südamerika 4: 1252. (1981)
Cumulopuntia tumida Ritter, Kakteen in Südamerika 4: 1254 (1981)
Opuntia dimorpha Förster, in Hamb. Gartens. 17: 167. (1861)
2) Cumulopuntia leucophaea (Philippi) Hoxey, comb. nov.
Basionym: Opuntia leucophaea Philippi, Anales Mus. Nac. de Chile, Sect. 2 Botany 8: 27 (1891)
Type: Chile, Province Tarapacá, near Usmagama, March 1885 Rahmer s.n. SGO 052672
Cumulopuntia unguispina (Backeberg) Ritter, Kakteen in Südamerika 4: 1251 (1981)
Cumulopuntia tubercularis Ritter, Kakteen in Südamerika 3: 888 (1980)
Tephrocactus mirus Rauh & Backeberg in Backeberg, Descr. Cact. Nov: 8. (1956)
Tephrocactus muellerianus Backeberg, Descr. Cact. Nov: 8. (1956)
Tephrocactus pseudorauppianus Backeberg, in Backeberg & Knuth, Kaktus-ABC: 112, 410. (1936)
3) Cumulopuntia zehnderi (Rauh & Backeberg) Ritter, Kakteen in Südamerika 4: 1249 (1981).
Cumulopuntia alboareolata (Ritter) Ritter, Kakteen in Südamerika 4: 1249 (1981)
4) Cumulopuntia corotilla (K.Schumann ex Vaupel) E.F.Anderson, Cact. Succ. J. (US) 71(6): 324. 1999
Opuntia campestris Britton & Rose, Cactaceae 1: 99. (1919)
Tephrocactus mistiensis Backeberg, in Backeberg & Knuth, Kaktus-ABC: 110, 410. (1936)
5) Cumulopuntia ignota (Britton & Rose) Ritter, Kakteen in Südamerika 4: 1250 (1981)
Taxa from the Nazca valley of uncertain classification and requiring further study:
Tephrocactus bicolor (Rauh & Backeberg) Rauh, in Sitz. Heidelb. Akad. Wiss. 1958, 223 (1958)
Cumulopuntia galerasensis Ritter, Kakteen in Südamerika 4: 1249 (1981)
Cumulopuntia sp. (Puquio)
Backeberg, C (1958) Die Cactaceae Band 1
Britton and Rose (1919) The Cactaceae Volume 1
Hunt, D (2006), The New Cactus Lexicon
Iliff, J (2002) The Andean Opuntias, Studies in the Opuntioideae, Succulent Plant Research Volume 6
Leighton-Boyce, G & Iliff, J (1973) The Subgenus Tephrocactus
Rauh, W (1957) Beitrag zür Kenntnis der peruanischen Kakteenvegetation
Ritter, F (1980) Kakteen in Südamerika Band 2
Ritter, F (1980) Kakteen in Südamerika Band 3
Ritter, F (1981) Kakteen in Südamerika Band 4
Stafford, D (1939) Cacti of Southern Peru, The Cactus & succulent Journal of Great Britain 8: 15.
Weberbauer, A (1945) El Mundo Vegetal de Andes Peruanos
The author thanks Roy Mottram for his help in editing this article.
This article was originally published in Tephrocactus Study Group (the 'TSG Journal'), December 2009, Vol. 15, No. 4, pages 47-54 and 56-58. ©TSG and Paul Hoxey