A trip on the Ruta 5 in Argentina, along the bolivian border

Thomas Guerry © March 2020 There is a huge diversity of cacti in Argentina, and many areas allow travellers to contemplate a wide variety of species in a few days only.

The province of Jujuy is one of them, and in particular the Ruta 5 along the bolivian border, around the city of La Quiaca which is one of the main crossing points between Argentina and Bolivia. While going up to the north along the Ruta 9, connecting Buenos Aires to the bolivian border, one can come across many species of dwarf Opuntias near the city of La Quiaca.

One of them is Tephrocactus nigrispinus, one of the smallest species of the Tephrocactus. This species makes small clusters of around 20 centimeters in diameter, and makes bright red flowers, and fruits of the same color. The landscape seems barren, but this is only a feeling… Another very common species in the province of Jujuy is Maihueniopsis molfinoi, also called M. hypogaea or M. glomerata ssp hypogaea.

With M. camachoi and M. conoidea in Chile, this is one of the northernmost species of Maihueniopsis. Most have spines with a white basis and a dark tip, only located at the uppermost areolas of the segments, but a few plants have no spines at all, only glochids. But a few species are far more difficult to spot, because they are much more discreet and growing in specific environments.

This is the case of Cumulopuntia subterranea (formerly Puna subterranea), whose segments do not exceed the ground level from one or two centimeters. During the dry season, this is very difficult to spot in this very arid landscape, however they are here ! There is another Cumulopuntia in this area, which is probably closely related to Cumulopuntia boliviana, making bigger clusters than C. subterranea, but smaller than the ones of the typical form of C. boliviana. Once arrived in La Quiaca, we turned to the east, along the bolivian border, until arriving to a place that some call « the Oreocereus forest ». Many species of cacti grow in this place, but the first ones that we can see, because of their size and density, are Oreocereus.

Two species grow there : O. celsianus and O. trollii. are plants with eretec stems, up to two meters high.

Flowers are long and narrow, therefore they are adapted to be fecundated by hummingbirds. When mature, the fruits are bright yellow and contain several hundred of seeds each.

Oreocereus trollii are smaller plants, with crawling stems instead of erected ones, and with colorful spines visible through the layer of silks, similar to hairs, typical from th genus Oreocereus. Smaller but nevertheless easily visible, Lobivia ferox is a globular making big flowers, which are most of the time white. In rare cases, hybrids of Oreocereus celsianus and Lobivia ferox are created by the fecundation thanks to insects.

Those plants are smaller than Oreocereus celsianus, with spines and a green epidermis inherited from Lobivia ferox. Another omnipresent species along the slopes of the hills coverd by Oreocereus is Cumulopuntia boliviana, with particularly big segments and strong spines. There are two other species in this place, that are growing on the top of the hills and not on the slopes.

The first is Rebutia pygmaea, making very small heads barely exceeding 1 centimeter in height and diameter. Two varieties of Rebutia pygmaea grow there, one with orange/salmon flowers, the other with pink flowers.

Excepted during flowering time, it is extremely difficult to spot these tiny heads on the ground. The other plant, difficult to find because hardly exceeding the ground, is Neowerdermannia vorwerkii. After leaving the Oreocereus forest and going to the west of La Quiaca, we spotted some eye-catching patches of colour along the road.

This was a wonderful field of flowering Lobiva ferox, and all of these flowers had different colours, which is quite surprising for this species.

A little further on the road, one can find some other species typical from this area.

Among them, Parodia maassii is a superb species of the genus Parodia, with long gold hooked spines. This species makes beautiful dark orange flowers. There are few Austrocylindropuntia species in Argentina, but there is in this area Austrocylindropuntia shaferi, that makes long stems with pink to red flowers, and fruits containing a few big seeds only. There are again a few plants of Neowerdermannia vorwerkii, but this time hidden under bushes. A few Rebutia are hidden under the bushes as well, but without flowers they are difficult to identify ! There are many forms of Tunilla in north-west Argentina, to such extent that it is very difficult to distinguish different species.

This one is one of the most common ones, and is probably close to Tunilla soherensii. But the treasure growing in this north-west end of Argentina is the tiny and rare Yavia cryptocarpa.

This species, very appreciated by cacti lovers, is endangered because of its scarcity and of the lootings that happened on some localities. This plant grow in cracks, and is only distinguishable by its round shape in the middle of the sharp- edged stones.

The biggest plants are only 3 centimeters in diameter. Five Yavia are hidden on this picture, it is your turn to find them ! At the far end of the Ruta 5, before turning to the south, the northernmost village of Argentina stands there : Santa Catalina.

Slightly over 300 inhabitants live there, at around 3800 meters in altitude. Santa Catalina is the type locality of Maihueniopsis molfinoi, that we have already seen previously. Surprisingly, the fruits, that are small and red when ripe usually, are here a little bigger and rather yellowish, with only a reddish end. There is also an atypical Cumulopuntia, with fine black spines. This is probably one of the numerous forms of Cumulopuntia boliviana. The road along the bolivian border ends here, with these few flamingos.