Original Description

Echinocactus humilis Philippi, 1837, Fl. Atac. 23. 1860. Not Pfeiffer

"138. Echinocactus humilis Ph. E. parvus, subglobosus, depressus, circa 12 lin. latus, 10 lin. altos; costis circa 10-12; verrucis superioribus aculeos circa 10, cinereos, setaceos gerentibus, quorum peripherici divaricati, centralis credos; parum major, 12 lin. altos; aculeis verrucarum basalium vix 1½ lin. longis, setaceis ; corolla sulphurea, 9 ½ lin. longa.

Prope Paposo in detritu rupium ad pedes montium litoralium crescit."

Transferred to Copiapoa by P.C. Hutchison, 1953, Studies of South American Cactaceae, Cactus & Succulent Journal (USA), 25(2): 34-37; (3):63-72

Original description, see above, as Echinocactus humilis.

Britton & Rose, 1922, The Cactaceae (3): 89

The [four] following species are probably of this relationship [i.e. the genus Copiapoa], but too little is known of them to place them definitely:

Echinocactus humilis Philippi, Fl. Atac. 23. 1860. Not Pfeiffer, 1837.

Very small, depressed, subglobose, 2.5 cm. broad by 2 cm. high; ribs 10 to 12, tuberculate; radial spines 10 to 12, setaceous, spreading; central spine 1, 2.2 cm. long; flowers yellow, 2 cm. long.

Type locality: Paposo, Antofagasta, Chile.

Distribution: Antofagasta, Chile.

Paposo, the type locality of this species is on the coast north of Taltal. This species seems never to have been re-collected. It was not found in the Philippi Herbarium at Santiago and was unknown to Mr. Sohrens. The name being a homonym must be rejected.

Hutchison P.C.1953, Studies of South American Cactaceae, Cactus & Succulent Journal (USA), 25(2): 34-37; (3):63-72

It is perhaps surprising that this plant, known since 1837, and identified by Britton & Rose as requiring more study when they erected the Genus Copiapoa, did not formally join the genus until 116 years after its discovery.

Ritter F. 1980, Kakteen in Südamerika (3):1066

 

Ritter discusses this highly variable taxon and its many forms that he believes are found between Paposo and Blanco Encalada.  He points at Hutchison's comments that the plants around the type-locality at Paposo has mainly juvenile spination forms on old taproots.  Ritter concludes that this is due to the frequent grazing damage inflicted by donkeys.

C. taltalensis and C. paposoensis are closely related

Taylor N. P. 1981, A commentary on Copiapoa, The Cactus and Succulent Journal of Great Britain, 43(2/3): 49-60

Taylor suggests that  this is a very complex species or species aggregate, perhaps representing geographical varieties or, in some cases, critical species, listed here in sequence from north to south:

C. tocopillana, C. tenuissima, C. variispinata, C. paposoensis, C. taltalensis, C. longispina and possibly C. chaniaralensis and C. esmeraldana.

Reports Ritter's & Taylor's observations

Adriana Hoffmann retains the species that includes varieties humilis, esmeraldana, longispina, taltalensis and paposensis

[translated extract] Species described from near the base of the coastal mountains near Paposo. Hutchinson (1953, Cact. Succ. J. USA: 34), in a comprehensive study designated material coming from hills to north of Paposo as neotype..

Ritter's description is supplemented by Meregali's personal observations.

Distribution. According to Ritter (1980), C. humilis spreads to the north of Paposo, towards Blanco Encalada, and introduces several more or less similar forms that could be described as local varieties.

C. humilis is part of a large group of other taxa of which the precise systematic status is not clear at present, spreading between Tocopilla and Chañaral, with another  taxon present to the south of Copiapó (C. longispina, Sierra Hornillos): it seems likely that many of the forms described as species can be regarded under humilis, as subspecies or as forms.

In considering Copiapoa humilis species, we need to bear in mind the remarkable differences between young plants, with to short, thin spination and the darker coloration of the body compared to the more robust adults with longer and sturdy, flexible spines. In general the material distributed and correctly identified as C. humilis includes FR-464; Lau-810, Paposo; KK- 118, Paposo and KK-1691, Mine Julia etc), but could also include hybrids. It seems that the form distributed by Knize under the name of C. maritima (KK-1709, Paposo) also belongs to humilis.

The authors recognise C. humilis as a good species.

Distribution: Taltal to Caleta Colorado

Charles retains the species that now also includes varieties humilis, esmeraldana, longispina, taltalensis, and adds varieties tenuissima, tocopillana and varispinata. 

Hunt D. (Ed.) 2002,
Cactaceae Systematics Initiatives 13:12

Expands the species to include:
Copiapoa humilis ssp. tocopillana (Ritter) D. Hunt
Copiapoa humilis ssp. varispinata (Ritter) D. Hunt

Notes on the Copiapoa humilis complex and the description of a new subspecies: Copiapoa humilis ssp. australis

Hoffmann A.E. & Walter H.  2004
Cactaceas en la flora silvestre de Chile (2nd Ed.): 146

Lists 6 subspecies:

• humils

• australis

• longispina

• tenuissima

• tocopillana

• varispinata

Hunt D. (Ed),  2006
New Cactus Lexicon

Lists 6 subspecies:

• humils

• australis

• longispina

• tenuissima

• tocopillana

• varispinata

Distribution

PK Comments

Hutchison points at the borer larvae of parasitic insects as a proven predator while Ritter mentions donkeys as the cause of damage to mature plants. In addition, in 2001 we observed what appeared to be a plague of rodents (mice?) in progress, clearly damaging plants.

Hutchison raises some interesting questions:

• Will the plant bloom freely and set viable seed in cultivation ?

• Will it reproduce its peculiar morphological attributes if grown from seed or from cuttings?

• If, by contrast, a tuberous root develops, will it form before or after the plant stem becomes mature?

In cultivation in the UK, C. humilis are able to flower from immature stems at an early age (c. 2 years from germination) and set viable seed.

Seedlings naturally produce the huge tap root, starting from germination, i.e. before the plant stem becomes mature. Plants reach their mature phase from about year 3, producing copious wool in the apex. Yet this mature growth seems 'softer' than seen on plants at the type locality above Paposo. Some C. humilis plants in my collection (especially plants labelled C. pendicolor) have reached a significant biomass while retaining a 'juvenile element' in their appearance.

Some of Hutchison's questions remain as yet unanswered:

• What is the species of insect which attacks this plant and what inter-relationships, if any, exist between their respective life-cycles and climate?

• The answers to certain of these questions may suggest an explanation of the morphological anomalies of this species in terms of the relative significance of environmental and genetic factors involved.