Copiapoa Britton & Rose

Walter, Helmut E. & Guerrero, Pablo C., 2022, Towards a unified taxonomic catalogue for the Chilean cacti: assembling molecular systematics and classical taxonomy, Phytotaxa 550 (2), pp. 79-98 : 88-90

Copiapoa Britton & Rose :

—This endemic genus has formerly been regarded as a member of the tribe Notacacteae Buxb. , e.g. by Barthlott & Hunt (1993),Anderson (2001), Hoffmann & Walter (2004), and Hunt et al. (2006). Molecular studies by Nyffeler (2002), Korotkova et al. (2010), Nyffeler & Eggli (2010), Arakaki et al. (2011), and Hernández-Hernández et al. (2011) suggested that Copiapoa is not a member of this tribe as it appears isolated on its own clade. Nyffeler & Eggli (2010) treated Copiapoa as a genus of uncertain relationship (incertae sedis), whereas Korotkova et al. (2010) suggested a close relation between Copiapoa and Calymmanthium F.Ritter , although morphology, ecology, and distribution of the two genera are very different. In Nyffeler (2002) and Hernández-Hernández et al. (2011), both genera appear together in a polytomy. Finally, Hunt et al. (2013) accepted Doweld`s (2002) recognition of a “tribe Copiapoae ”. In consideration of the complex situation and the lack of data, we here consider Nyffeler & Eggli’s (2010) concept (incertae sedis).

Several infrageneric classifications of Copiapoa based on morphological characters had been proposed by Ritter (1980) [two subgenera (subgenus Pilocopiapoa F.Ritter and subgenus Copiapoa F.Ritter ) and five unnamed sections]. Doweld (2002) proposed three sections (sect. Pilocopiapoa (F.Ritter) Doweld (one serie), sect. Echinopoa Doweld (two series: Echinoidei Doweld and Cinerei Doweld ), and sect. Copiapoa (two series: Humilis Doweld and Copiapoa ); mainly based on general morphological data ( Hunt 2001) and stem mucilage and/or root types. Taylor (2001) proposed two subgenera (subgen. Pilocopiapoa (F.Ritter) F.Ritter ) and subgen. Copiapoa (five unformal “groups”: “ marginata ”, “ cinerea ”, “ hypogaea ”, “ cinerascens ”, and “ humilis ”). None of these concepts were corroborated by the molecular phylogeny presented by Larridon et al. (2015) whose data retrieved the four well supported sections: sect. Pilocopiapoa (with 1 species), sect. Mammilopoa Helmut Walter & Larridon (1 species), sect. Copiopoa [with two subsections: subsect. Cinerei (Doweld) Helmut Walter & Larridon (2 species), subsect. Copiapoa (22 species)], sect. Echinopoa (Doweld) Helmut Walter & Larridon (5 species) and two basal unnamed monotypic clades (“ Copiapoa australis ” and “ Copiapoa laui ”) (see the proposed key below). According to the results of the phylogenetic analyses five speciescomplexes were split: C. humilis (Phil.) Hutchison , C. cinerea (Phil.) Britton & Rose , C. taltalensis (Werderm.) Looser , C. montana F.Ritter , and C. coquimbana (Rümpler) Britton & Rose.

1. Bract scales numerous distributed all over pericarpel and hypanthium, axils very woolly; ribs to 3.5 cm high (Sect. PILOCOPIAPOA ).......................................................................................................................................................... 31. C. solaris

- Bract scales few, mainly near hypanthium rim, axils only rarely with fine tiny hairs; ribs ≤ 2 cm high............................................2

2. Ribs in mature plants dissolved into ±conical tubercles; stems soft to the touch ..............................................................................3

- Ribs not dissolved into conical tubercles (except for C. longispina ), stems soft or not so................................................................4

3. Tubercles obtuse; epidermis ±pruinose; ribs 8-10 (unnamed Section) ......................................................................... 5. C. australis

- Tubercles pronounced; epidermis not pruinose; ribs more numerous................................................................................................5

4. Stems dwarf (1–2 cm diam.); tubercles and spines minute (Unnamed Section .................................................................. 21. C. laui

- Stems to 8 cm diam.; tubercles large, spines much longer (Sect. HUMILIS)............................................................... 19. C. humilis

5. Plants usually mound-forming; ribs to 2 cm high; fruits large, 1.5–2.0 cm (Sect. ECHINOPOA) ...................................................6

- Plants mound-forming or not; ribs lower; fruits <1.5 cm (Sect. COPIAPOA ) ................................................................................ 10

6. Tubercles inconspicuous; roots fascicular..........................................................................................................................................7

- Tubercles well pronounced; taproots of different lengths ..................................................................................................................8

7. Mounds up to 2 × 1.5 m; stems often pruinose; ribs to 30; areoles far apart .............................................................. 11. C. dealbata

- Mounds much smaller, ribs to 15; stems never pruinose; areoles closely set ......................................................... 14. C. echinoides

8. Stems 5–8 cm diam.; tubercles with large chins .................................................................................................... 16. C. fiedleriana

- Stems 8–18 cm diam., usually chinless ..............................................................................................................................................9

9. Stems 8–12 cm diam.; new spines black, to 4 cm ................................................................................................. 10. C. coquimbana

- Stems to 18 cm diam.; new spines brownish, later golden yellow, to 6 cm .................................................................... 3. C. armata

10. Rib number up to 40; roots always fascicular; stem tissue very hard (Subsect. CINAREI .............................................................11

- Rib number <26, roots various; stem tissue not very hard (Subsect. COPIAPOA ).........................................................................12

11. Plants forming loose groups or solitary; apical wool grey.............................................................................................. 8. C. cinerea

- Plants forming large dense mounds; apical wool (orange)-brown.............................................................................. 17. C. gigantea

12. Ribs dissolved into conical tubercles ....................................................................................................................... 23. C. longispina

- Ribs not so ........................................................................................................................................................................................13

13. Stem tissue somewhat hard (except for C. hypogaea )......................................................................................................................14

- Stem tissue ±soft-fleshy ...................................................................................................................................................................29

14. Bract-scales on hypanthium and fruits large, broad and fleshy; hilum very large ................................................... 26. C. megarhiza

- Bract scales and hilum not as above.................................................................................................................................................15

15. Rib number usually 15–25................................................................................................................................................................24

- rib number usually low (8–15) .........................................................................................................................................................16

16. Roots fascicular ................................................................................................................................................................................17

- Roots usually tuberous or long to short taproots ..............................................................................................................................18

17. Stem diam. 4–7 cm ............................................................................................................................................... 9. C. conglomerata

- Stem diam. larger, to 15 cm ................................................................................................................................ 23. C. longistaminea

18. Interior perianth segments yellow, without red mid-stripes; style whitish-yellow ..........................................................................19

- Interior perianth segments yellowish with red mid-stripes of different widths; style pink to red....................................................22

19. Plants mound-forming; stems elongating; spines short (1.5–2.5 cm), straight ................................................................................20

- Plants solitary to few-headed; stems only slightly elongating; spines long (to 5 cm), partly curved ...................... 32. C. taltalensis

20. Rib tubercles much pronounced, furrows undulate.......................................................................................... 30. C. serpentisulcata

- Ribs only somewhat tuberculate, furrows not undulate ...................................................................................................................21

21. Plants forming loose mounds; stems ca. 8 cm diam.; longer ones prostrate; fruit 1cm ......................................... 12. C. decorticans

- Plants forming compact mounds; stems apically flattened, to 15 cm diam.; stems not prostrate; fruit 1.5 cm ................................... .................................................................................................................................................................................. 7. C. cinerascens

22. Plants mound-forming; stems green, not pruinose, to12 × 50 cm; flowers 3.0– 4.5 cm, funnel-form; spines to 5 cm, thick .............. ..........................................................................................................................................................................................................23

- Plants solitary to few-headed; stems grey-green, ±pruinose, to 8 × 20 cm; flowers small, (2.5 cm), campanulate; spines short, to 2.5 cm, thin .................................................................................................................................................................... 2. C. aphanes

23. Mounds usually loose, spines to 10, (red)-brown, partly curved ................................................................................ 29. C. rupestris

- Mounds compact, spines to 20, completely hiding stem, black, straight ............................................................... 13. C. desertorum

24. Plants large, forming loose or dense mounds; rib tubercles inconspicuous, areoles closely set in older plants ..............................25

- Plants small to medium-sized, not much elongating, few-headed, rib tubercles pronounced; areoles not crowded ........................... ..........................................................................................................................................................................................................27

25. Plants forming large, dense mounds; stems to 15 cm diam., pruinose.................................................................... 4. C. atacamensis

- Mounds smaller, loose; stems to 10 cm diam., only sometimes pruinose........................................................................................26

26. Stems light grey-green, sometimes pruinose, spines to 3 cm ...................................................................................... 6. C. calderana

- Stems green, never pruinose, spines to 5 cm ............................................................................................................ 25. C. marginata

27. Plants subglobose, temporarily geophytic; epidermis grey-brown ........................................................................... 20. C. hypogaea

- Plants globose to somewhat elongate; epidermis grey-green...........................................................................................................28

28. Stems to 10 cm diam., not pruinose; areoles large ..................................................................................................... 28. C. montana

- Stems 4–7 cm diam.; ± pruinose; areoles smaller ...................................................................................................... 22. C. leonensis

29. Plants mound-forming; stems to 10 cm diam.; tubercles not chinned ................................................................... 18. C. grandiflora

- Plants solitary to few-headed; stems 3–7 cm diam.; tubercles ±chinned .........................................................................................30

30. Ribs broad and flattened............................................................................................................................................ 27. C. mollicula

- Ribs narrower and deeper.................................................................................................................................................................31

31. Flowers large, broadly campanulate; stems to 7 cm diam. green, not pruinose................................................... 15. C. esmeraldana

- Flowers small, narrowly funnel-form; stems to 4 cm, grey-brown, somewhat pruinose........................................ 1. C. angustiflora

Several new taxa in the genus Copiapoa were recently proposed in different journals. As none of them had been included in the sampling of a molecular-based study, we decided not to accept them as long as they are not corroborated by molecular phylogenies: Copiapoa coquimbana subsp. rubrispina Piombetti in Xerophilia 4(3): 76. 2015; Copiapoa longispinea subsp. imperialis Piombetti in Xerophilia 4(3): 78. 2015; Copiapoa corralensis Schaub & Keim in Cactus Explorer 16: 48. 2016; Copiapoa fusca Schaub , Cactus Explorer 16: 42. 2016; Copiapoa humilis subsp. matancillensis Schaub & Keim in Cactus & Co 20(1): 15. 2016.

Concerning Copiapoa gigantea Backeb., Hunt et al. (2006) use the epithet “ haseltoniana ” (instead of “ gigantea ”) in the combination C. cinerea subsp. haseltoniana (Backeb.) N.P.Taylor (see species list). The results by Larridon et al. (2015, 2018b) suggest that this taxon is not closely related to C. cinerea and should thus be considered as a valid species. Also, C. gigantea has priority over C. haseltoniana at species level (ICN, Art. 11.2) as below reported.