Trichocereus macrogonus is a cactus endemic to the Andean mountain ranges of South American countries Ecuador, Peru, and Bolivia, where it is planted as fencing and regarded as a guardian spirit. Its large magnolia-like flower petals and vascular mucilage are also used as shampoo, clay hardening agent, and wound salve. In times past large stands of this plant provided shelter for people crossing mountains. Now the cactus is cultivated globally for its large flowers, statuesque branches, and historical significance. Some common names for this plant are abuelo, achuma, aguacolla, ahuacoya, awacoya, hahuacolla, hahuacollay, hawaqollay, huachuma, wachuma, san pedro, gigantón, bolivian torch, ecuadorian torch, peruvian torch, or andean torch.
Original horticultural description of Trichocereus macrogonus was made as Cereus macrogonus by Christoph Friedrich Otto and Joseph zu Salm-Reifferscheidt-Dyck in 1850, and the name is seen in cactus guides before 1846. This is of course not when the plant was first discovered or named by humans, but rather when it was first given binomial Latin name in European botanical literature. The plant had already been cultivated for thousands of years in the Andes Mountains and introduced to the Canary Islands and Spain before Otto and Salm-Dyck described it growing in Berlin, Germany at Botanisches Garten with no known origin:
(59.) C. MACROGONUS II. Berol. C. caule erecto columnari subglaucescenti-laeteviride 6-7 angulato, costis turgidis obtusissimis apicem versus obrepandis ad pulvillos crenato-plicatis et colore intensius viride arcuatim notatis, pulvillis confertis griseo-tomentosis, aculeis rigidis abbreviatis brunneis, in pulvillis junioribus 8-10, in senioribus 19-20, erecto-patulis, 3 -+ validioribus. (Nob.) Caulis hucusque 8-10 pollicaris, diametro fere bipollicari. Costa rotundate, farctz, superne ad pulvillos plicatz et arcu viridiore notata. Pulvilli lin. 3-4 distantes parvuli, grisei. Aculei primo subregulariter dispositi, 7-9 radiantes cum centrali 1; sed mox (aculeis novis enascentibus) sine numero a ordine normali erecto-patuli, graciles, brunnei, 3-4 paulum validioribus, lin. 5 longis.
The Latin word macrogonus is somewhat descriptive and means large-angle, referring to the larger and more angled sloping ribs of Trichocereus plants. This term macrogonus was made to compare Trichocereus against the flatter and thinner ribbed Cereus species with red skinned fruits that from a distance resemble apples of the Eurasian Malus tree. In 1905 botanist Alwin Berger proposed Trichocereus for Cereus macrogonus and similar Andean cacti being attributed to Cereus at the Missouri Botanical Garden, as when the areoles of Trichocereus begin to flower they produce thread-like hairs. Berger defined plants using flower and fruit differences between Trichocereus and Cereus cacti, which have both in basic form similar large white night-blooming flowers:
III. Flowers single from the areoles.
A. Flowers actinomorphous.
1. Flowers short, more or less campanulate or tubular.
a. Flowers tubular.
* Ovary and tube with wool and hairs or bristles.
+ Ovary densely woolly; petals short, spatulate; fruit very woolly and prickly.
XII. TRICHOCEREUS A. Berg.
Ovary often with a few spines and with copious white wool, also the tube woolly in the axils of the scales; fruit red, often prickly. pulvilli more or less raised.
There is a problem with the above summary incorrectly stating the Trichocereus flower ovary has a few spines and that fruit is red and prickly. There are no ovary spines, and though fruit can have green-pink skin when ripe the color is typically green. The green skin is scaly and hairy and often splits open to expose white flesh and black seeds while still attached to the branch. The error is not replicated in the description Berger made following the summary:
XII. TRICHOCEREUS A. Berg. Ovary and tube with more or less densely imbricated acute scales, from the axils of which rise long and curled or woolly hairs in great profusion, but no bristles; sepaloid and petaloid perianth leaves numerous; stamens numerous, in two groups; style as long or longer with numerous stigmata. Fruit uncolored, roundish, scaly and hairy, with the dried remains of the flowers more or less persistent. Flowers showy, nocturnal, white, yellowish or red, trumpet-shaped.- Plate 8, J. 1-3. Chiefly Andean species: - Cereus (Trichocereus) andalgalensis Web. 1. c. 168. - Argentina. C. (Trichocereus) Bridgesii Salm. 1. c. 107. - Bolivia. C. (Trichocereus) candicans GIll. 1. c. 69. - Argentina. C. (Trichocereus) chilensis Colla. 1. c. 61. - Chile. C. (Trichocereus) fascicularis Meyen. 1. c. 57. - Peru. C. (Trichocereus) Huascha Web. 1. c. 70. - Argentina. C. (Trichocereus) lamprocklorus Lam. 1. c. 60. - Argentina. C. (Trichocereus) macrogonus Salm. 1. c. 115. - Andes? C. (Trichocereus) nigripilis Phil. 1. c. Nachtr. 20. - Chile. C. (Trichocereus) Pasacana Web. 1. c. 77. - Argentina. C. (Trichocereus) pterogonus Lem. 1. c. 153. - New Granada. C. (Trichocereus) Spachianus Lem. 1. c. 67. - Argentina. C. (Trichocereus) strigosas Salm. 1. c. 68. - Argentina. C. (Trichocereus) thelegonus Web. 1. c. 78. - Argentina. The description of the flower of Cereus macrogonus Salm in K. Schumann's Monographia is not correct; see Monatsschrift für Kakteenkunde, 1904, p. 190. Cereus andalgalensis Web. is the same as Cereus Huascha Web. var. rubriflora Web., as I have been informed by Weber himself. The genus Echinopsis comes so near to this subgenus that there seems to be no obstacle, except for its seeds, to reuniting it with Cereus, as done by Pfeiffer and Otto, and by Bentham and Hooker (Gen. Plant. 1: 849). Cereus candicans Gill. and O. lamprochlorus Lem., on the other hand, have been considered by Weber as Echinopses. Echinopsis obrepanda K. Sch., E. cinnabarina Lab. and E. Pentlandit Salm, have been included by other authors under Echinocactus.
In 1909 cacti specialist Vincenzo Riccobono agreed with the separation of these plants into Trichocereus in his work Bollettino delle Reale Orro Botanico di Palermo volume 8:
Trichocereus BERGER, Revis. gen. Cereus. In Missour. Bot. Gard. Vol. XVI. 1905. p. 73 (pro subgenere). Sinonimi: Cereus, AUCT. CARATTERI: Fiori vistosi, notturni, bianchi o bianco-rosei, imbutiformi; ovario e tubo con squame più o meno densamente embriciate, acute, dalla cui ascella sorgono in grande abbondanza lunghi e ricurvi peli lanosi, mai setole; lacinie del perigonio numerose; stami numerosi e declinati: stilo di uguale lunghezza, con numerosi stimmi; frutto rotondo, squamoso e peloso con il perigonio più o meno persistente. Sp. 1.° Trichocereus macrogonus (BERG. 1. c. p. 83). Sinonimi: Cereus macrogonus, OTTO in Cact. hort. Dyck. 46 et 203. — LAB. Monog. Cact. p. 352, — K. SCHUMANN. Monog. Cact. p. 115. Pusto alto m. 3, ramoso in basso con rami tortuosi, ascendenti, che misurano l'altezza da m. 1 a m. 2, verde-scuro, nella nuova vegetazione cenerino, con 7-8 coste converse, rotondate, leggermente sinuate e con una linea a forma di V sopra le areole: areole distanti fra di loro cm. 2, provviste di tomento grigio e 8-10 spine brune, radiali, che variano in lunghezza da mill. 5 a cm. 2, una centrale, spesso duo, lunghe 4 cm., le spine nella nuova vegetazione sono giallo-brune e di lunghezza maggiore, specialmente la centrale che si allunga fino a cm. 10 circa. Fiori inodori, imbutiformi, del diam. del lembo a completo sbocciamento di cm. 12; tubo lungo cm. 7, verde, solcato squamoso e lanugginoso, squame lungo il tubo brevi, quelle presso le lacinie esterne oblungo-lanceolate; ovario con squame embriciate, verdi provviste di lunga lanuggine alla base. Lacinie in più serie, le esterne oblungo-lanceolate verde-pallido, più scure verso l'apice, le interne obovate, bianco- puro, con breve mucrone molle. Stami con filamenti bianco-verdastri, che non oltrepassano il lembo del fiore, antere bianco-giallognole: pistillo con stilo bianco-verdognolo, che oltrepassa per poco gli stami e con stimma a 15 divisioni lineari giallognole. Bacca verde-oscura, sferica del diam. di cm. 5 con base dilatata ed appiattita, squamosa, squame embriciate con apice libero e molta lana lunga nera che le avvolge; mesocarpio bianco con piccoli e molti semi neri. Fiorisce di notte: Settembre. PATRIA : Ande. OSSERVAZIONI: La pianta qui fiorita è un bellissimo esemplare caratteristico, i cui rami si allungano, curvandosi pel troppo peso sul suolo, poscia, rialzandosi verticalmente, formano delle bellissime e robuste colonne in vicinanza del fusto principale. Questo speciale carattere non fu dai diversi autori accennato, forse perché descrissero piante troppo giovani.
Nathaniel Lord Britton and Joseph Nelson Rose published results of their 1918 field trip to Ecuador in their 1920 Volume 2 of their authoritative The Cactaceae. In this second volume they concurred with the growing consensus that Trichocereus is different from Cereus:
24. TRICHOCEREUS (Berger) Riccobono, Boll. R. Ort. Bot. Palermo 8: 236. 1909. Columnar plants, more or less branched; ribs few to numerous, either low or prominent, usually very spiny; flowers nocturnal, large, funnelform, the perianth either persistent or separating from the fruit by abscission; perianth segments elongated; stamens numerous, filiform, arranged in two groups; stigma-lobes numerous; ovary and flower tube bearing numerous scales, their axils bearing long hairs; fruit without bristles or spines, dull colored. Type species: Cereus macrogonus Otto. This genus consists of two species, confined to South America. It is based on the sub-genus of the same name by Berger, but only 2 of Berger's species were transferred to it by Riccobono. While the flowers of this genus suggest Echinopsis, we can not agree with Berger's suggestion that the genera might be united. The name is from the Greek and signifies thread-cereus, referring to the hairy flower-areoles.
Britton and Rose further described another variety then unpublished in literature encountered in Ecuador by Rose named Trichocereus pachanoi in honor of Rose's field companion in Ecuador and fellow botanist Abelardo Pachano Lalama. Today the plant is called T. macrogonus var. pachanoi:
7. Trichocereus pachanoi sp. nov. Plants tall, 3 to 6 meters high, with numerous strict branches, slightly glaucous when young, dark green in age, ribs 6 to 8, broad at base, obtuse, with a deep horizontal depression above the areole; spines often wanting, when 1 to 2 cm. long, dark yellow to brown: flower-buds pointed; flowers very large, up to 23 cm. long, borne near the top of branches, night-blooming, very fragrant; outer perianth-segments brownish red; inner perianth-segments oblong, white; flaments long, weak, greenish; style greenish below, white above; stigma-lobes linear, yellowish; ovary covered with black curled hairs; axils of scales on flower-tube and fruit bearing long black hairs. Collected by J. N. Rose, A. Pachano, and George Rose at Cuenca, Ecuador, September 17 to 24, 1918 (No. 22806, type). This species is widely cultivated throughout the Andean region of Ecuador, where it is grown both as an ornamental and as a hedge plant. In some of the lateral valleys on the western slope of the Andes it appears to be native, as for instance above Alausi, but as it has doubtless long been cultivated it is impossible to be sure of its natural habitat. It is known to the Ecuadoreans as agua-colla or giganton and has been passing in Ecuador under the names of Cereus peruvianus and Cereus gigantens. It is named for Professor Abelardo Pachano of the Quinta Normal at Ambato, Ecuador, who accompanied Dr. Rose in 1918 on his travels in the high Andes of Ecuador. This species belongs to the high Andes, ranging from 2,000 to 3,000 meters in altitude. In the Chanchan Valley it certainly comes down to about 2,000 meters and overlaps the upper range of Lemaireocerens godingianus, which differs from it greatly in habit and flowers. Different as the two plants are, Richard Spruce, keen botanist as he was, confused them, as the following quotation will show; the part in italics refers to the Lemaireocereus: "The brown hill-sides began to be diversified by an arborescent Cactus, with polygonal stems and white dahlia-like flowers, which, Briareus-like, threw wide into the air its hundred rude arms. Lower down, at about 6,000 feet, I saw specimens full 30 feet high and 18 inches in diameer." Figure 196 shows the top of a large plant growing on the sides of a cliff on the outskirts of Cuenca, Ecuador, photographed by George Rose in September 1918.
Britton and Rose found many botanical garden and herbarium collections of Cereus macrogonus to be of species other than Trichocereus. Schumann's 1890 text Flora brasilensis depicts a Pilocereus from Brazil calling it Cereus macrogonus. The appearance of Pilocereus aligns somewhat with the 1850 Salm-Dyck description of Cereus macrogonus, but the flowers, spines, branching habits, and other features of Trichocereus and Pilocereus are different.
Britton and Rose provided this understanding of Trichocereus macrogonus plus insight into its taxonomical origins within botany:
8. Trichocereus macrogonus (Salm-Dyck) Riccobono, Boll. R. Ort. Bot. Palmero 8: 236. 1909. Cereus macrogonus Salm-Dyck, Cact. Hort. Dyck. 1849. 203. 1850. Eriocereus lephraeanthus Riccobono, Boll. R. Ort. Bot. Palertio 8: 244- 1909- Stem probably tall, stout, but in cultivation often slender, bluish green, especially on young growth; ribs usually 7, low and rounded, 1.5 cm. high, separated by acute intervals; areoles large, 1.5 to 2 cm. apart; spines several from an areole, acicular, brown; radial spines 5 to 8 mm. long; central spine about 2 cm. long; flowers probably large and white; fruit unknown. Type locality: Not cited. Distribution: South America, but not known definitely in the wild state. This species is represented in the New York Botanical Garden by a live specimen from Kew, which we consider typical. Salm-Dyck described it from specimens growing in the Botanical Garden at Berlin, but did not know their origin.
Due to changes in botanical documentation standards and Salm‑Dyck and Otto not knowing where the cactus came from, there was some uncertainty by Britton and Rose as to which exact plant Salm‑Dyck and Otto described. Over time the name Trichocereus macrogonus fell out of general use as people felt the names provided by Britton and Rose provided more usefulness.
In 1974 cacti botanists claimed Trichocereus and Lobivia — a genus of small mounding cactus with which many colorful Trichocereus hybrids have been made — to be Echinopsis, based on similar flower and seed shapes as well as the ability to hybridize. People disagreed with the botanical grouping of Trichocereus and Lobivia within Echinopsis and kept using old Trichocereus names, using Britton and Rose as guidance. To this day Trichocereus can still be found sold as Echinopsis or even Cereus sometimes, but the Trichocereus name has been restored within botany.
Most old Trichocereus names are now considered synonyms of T. macrogonus var. macrogonus or were transferred to other species. By collapsing most Trichocereus into Trichocereus macrogonus, many names were removed, though growers continue to cultivate under old names.
Contrary to the popular understanding of cacti, Trichocereus are not quite desert cacti but closer to jungle cacti. Their equatorial environment does not see long hot summer days or long cold winter nights. Instead, daily temperatures are moderate, it rains often, and plants are found growing on fast draining rock along streams and hills and shade trees. If freezes and heatwaves are uncommon where you live, you can grow Trichocereus outside.
A wall of Trichocereus in bloom is amazing, and Trichocereus flowers are compatible with Cereus, Corryocactus, Echinopsis, Leucostele, Lobivia, and Soehrensia pollen. Many interesting Trichocereus hybrids with vibrant colors, tasseled petals, and interesting features are cultivated in nurseries across the world.
Abundant fruit of the variety T. cuzcoensis is harvested as food crop, but unlike the venerable Opuntia pad rich in nutrients, Trichocereus branches are ornamental and should not be eaten as vegetables due to containing hordenine and tyramine, leading to vasoconstriction, high blood pressure, migrane, and nausea in healthy people, and potential hypertensive crisis, stroke, and death for people with heart problems or monoamine metabolism compromised by monoamine oxidase inhibitors. However, one interesting botanical fact learned by Andean people is that the negative effects of Trichocereus consumption are diminished by chewing Erythroxylaceae coca leafs. Please appreciate these plants, their glowing skin, sun-catching spines, and big beautiful flowers with your eyes and heart. On bloom nights, you should use your nose and camera to appreciate them too.
These Bolivian plants are often found growing with 4–5 ribs and 0–3 spines and may not always fit botanical descriptions of Trichocereus macrogonus above, yet horticulturalists and Andean people consider them Trichocereus plants. Perhaps more varieties will be accepted, but current botanical consensus is these are forms of Trichocereus macrogonus.
It is regarded that all T. scopulicola in horticulture are descendents from open pollinated seedpods collected by Friedrich Ritter in Tarija at a location he named FR991. The location is unknown today.
Argentinian T. terschekii is a massive plant with flowers smaller than Trichocereus macrogonus. Its botanical name is Leucostele terschekii now.