At the Tephrocactus Study Group Meeting on the 8th May 2011 I gave an overview to the members present of the Opuntioid genera and species that are found in Peru. Alan Hill has asked me to summarise the talk for publication in the Journal. I based my presentation around the generic classification of the New Cactus Lexicon so five Opuntioid genera are found in Peru although I added a sixth for a widespread but non-native introduction. I decided to include 2 non-native species overall because although both are introduced by man, the introductions likely occurred many centuries ago in pre-Columbian times.
The summary of the genera and species covered:
The genus Opuntia in this work just includes the species with flat padded segments. The genus is not well represented in Peru and the majority of species are found in North America. Four species are found in Peru although one is introduced.
Opuntia ficus-indica is a domesticated species widely cultivated throughout the Americas and Peru is no exception. It is likely the species originated in Mexico. It is a large, flat padded-type Opuntia, which can grow into a small tree (Fig. 1). The spination is quite variable and plants can range from completely naked segments to having one or two short white spines. The flowers are usually yellow. The fruits of the plant are known as “Tuna” and are commonly sold in markets or at small stalls in the street. The fruits are skinned and the juicy pulp inside is eaten. Opuntia ficus-indica is also widely cultivated as a host plant for the Cochineal insect and I have seen whole fields given over to this cash crop (Figs. 2 and 3). In the village of La Joya, near Arequipa, shops advertise for the purchase of the Cochineal insects which are then used as a red dye. The introduction of Opuntia ficus-indica in Peru probably occurred a very long time ago through trade between the pre-Columbian peoples of present day Peru and Mexico. Plants are often found near villages but sometimes are found in more wild areas. This probably indicates the area used to be inhabited in pre-Columbian times but that conditions are favourable enough to allow the plants to propagate themselves unaided today.
Fig. 1. Opuntia ficus-indica PH640.06. 13-2726. Rio Rupac, Sihuas to Huacrachuco road, Ancash, Peru. 2340m.
Fig. 2. Cultivated Opuntia ficus-indica PH950A.01 21-1753. La Joya, Arequipa, 1660m.
Fig. 3. Opuntia ficus-indica PH950A.01. 21-1754. La Joya, Arequipa, 1660m.
A cultivated plant with cochineal.
I am following Ritter and using the name Opuntia inaequilateralis for a plant I found in the Marañón valley in Ancash although it is far from certain this is the right name to use. My plant (Figs. 4 and 5) formed a low spreading bush plant with elongated and flattened pads. The flower was orange and the flower tube nearly naked. This plant was growing near to Opuntia quitensis but is clearly distinct from it. It is perhaps closer to Opuntia pubescens but with numerous differences such as larger and more flattened segments and a less fragile nature. Ritter used Opuntia inaequilateralis, a Berger name from 1905 for a similar looking plant he found in the Mantaro valley but with yellow flowers. This is also illustrated in the New Cactus Lexicon (Illus. 495.04) and is quite similar to my plant but matches Ritter by having yellow flowers. Further work is required on these Opuntia of the inter Andean valleys to see if they are all one species and if the name Opuntia inaequilateralis is correctly applied to them.
Fig. 4. Opuntia inaequilaterralis PH640.01. 13-2732. Rio Rupac, Sihuas to Huacrachuco road, Ancash. 2340m.
Fig. 5. Opuntia inaequilaterralis PH640.01. 13-2731. Same site.
This is a small growing Opuntia and is another species found growing very widely in the Americas. The New Cactus Lexicon records the distribution as Bolivia, Ecuador, Guatemala, Mexico, Peru, Paraguay and Venezuela. It is likely that the distribution is natural and is a result of the very fragile nature of the plants and ease by which the segments detach and root.
Opuntia pubescens is an old name from the 1840s based on material from Mexico. The Peruvian populations have been given more recent names such as Opuntia pestifer and Opuntia pascoensis by Britton and Rose and Opuntia infesta by Ritter. Synonym names such as 'infesta' and 'pestifer' give a good indication of the type of plant we are dealing with here. The species can form low spreading thickets of cylindrical or slightly flattened stems covered in sharp but barbed spines (Figs. 6 and 7). Brushing past the plants invariably detaches a few segments which fix themselves to shoes or clothing. I suspect most propagation is by detached segments rooting down but occasionally the yellow flowers are seen and fruits can develop. I have only observed mature fruits once which are reddish and quite small with only two or three seeds inside.
Fig. 6. Opuntia pubescens PH736.02. 15-1718. Puente Pasaje, Rio Apurimac, Apurimac. 1050m.
Fig 7. Opuntia pubescens PH736.02. 15-1719. Same site.
This is a much more interesting species of Opuntia and distinct within the genus. As the name suggests the original material came from near Quito in Ecuador but the species grows as far south as Apurímac in Peru. In Peru I have only found it growing as a small bush to 50cm high but the description says it can grow to 3m tall. The flattened pads are approximately round and with widely spaced areoles (Fig. 8). The spines, up to 5 per areoles, are quite strong and grow to 8cm in length. The flowers are the most interesting feature of this species. They are small up to only 2.5cm in diameter and the orange petals do not open widely. Sometimes the flower is completely embedded within a normal segment and I do not know of any other species which has that character. The flowers are reported to be dioecious and either male or female. Unfortunately the one time I observed flowers in habitat I did not closely examine the flowers to check this character but the one flower I did photograph appears to be missing the stigma and style so is a male (Fig. 9). The only other species of Opuntia that has separate male and female flowers is Opuntia stenopetala. Interestingly this species also shares similar but unusual pollen characters with Opuntia quitensis so perhaps they are closely related species growing in widely disjunct habitats.
Fig. 8. Opuntia quitensis PH641.05. Rio Maranon, Sihuas to Huacrachuco road, Ancash, 1750m
Fig. 9. Flower of Opuntia quitensis PH641.05. Same site.
This monotypic genus contains one widely distributed species found from Brazil, through Paraguay, northern Argentina, Bolivia and into Peru. Not surprisingly for a widespread plant various additions names have been erected but it is generally considered today to be one species.
This single distinct species is one of the tallest growing of all cacti and is reported to reach 20m or more in height (Fig. 10). It is not a well known plant in Peru and rarely encountered by cactus enthusiasts in that country. My encounter with this species occurred quite by accident when I was exploring a steep densely vegetated slope in a dry tropical valley in central Peru. Climbing was difficult with a lot of leaf litter covering loose rocks. I made extensive use of small trees and bushes to help pull myself up the slope until I saw in front of me a tree truck with cactus spines (Fig. 11) and I realised that I had found Brasiliopuntia brasiliensis. On looking up I could make out a canopy of “branches and leaves” which look remarkably like a typical tree. A fallen stem which had subsequently re-rooted allowed me to examine the segments in more detail (Fig. 12). Brasiliopuntia brasiliensis has two very distinct forms of growth. Firstly it grows cylindrical stems which with time become woody and form the structure of the tree. Secondly leaf-like pads form which are thin and only partially succulent. They emulate leaves in a normal plant and are deciduous. Both types of growth have widely spaced areoles and sparse spination. I observed that the leaf-like pads are usually growing horizontally with a different texture on the upper and lower sides. The upper side is exposed to the sun and has a darker green colour whereas the underside is a lighter green. I find it very interesting that this plant has successfully re-evolved leaf-like structures from stems after the Opuntioid ancestor lost them to replace them with photosynthetic stems.
Fig.10. Brasiliopuntia brasilensis PH779.01. 16-0552. West of Yurinaki, Rio Perene, Junin. 730m.
A mature specimen growing on a steep slope in woodland.
Fig. 11. Brasiliopuntia brasilensis PH779.01. 16-0549. West of Yurinaki, Rio Perene, Junin. 730m.
A close up of trunk of a mature tree. Note the areoles.
Fig.12. Brasiliopuntia brasilensis PH779.01. 16-0538. West of Yurinaki, Rio Perene, Junin. 730m.
A fallen stem that has rooted and produced a new shoot.
This article was originally published in Tephrocactus Study Group (the 'TSG Journal'), December 2011, Vol. 17, No. 4, pages 47-51, 54-56 and 60. © TSG and Paul Hoxey