Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Echinocereus

Cactaceae

Echinocereus

Copy permalink to share

1 Stem length 8-50× the stem diameter; stems erect to clambering or sprawling on supporting vegetation
1 Stem length 1-8× the stem diameter; stems erect to ascending or semiprostrate to decumbent.
  2 Stem length 3-8× the stem diameter; stems semiprostrate to decumbent.
    3 Tepals yellow, orange-red or purple proximally
    3 Tepals pink-purple, purple, white, green or yellow proximally
      4 Tepals proximally white or yellow, stems with 4-5 ribs
      4 Tepals proximally green to purple, stems with (5-) 7-9 (-10) ribs.
        5 Stems 1.5-3 cm in diameter, sprawling to decumbent; radial spines < 10 mm long
        5 Stems 3.2-4.5 (-8) cm in diameter, ascending to erect; radial spines 9.5-19 (-33) mm long
  2 Stem length 1-3× the stem diameter; stems erect or ascending.
          6 Radial spines thin and bristle-like, 2-8 (-25) mm long, appressed and pectinately arranged or more or less porrect; tepals pink-purple
             7 Spines strongly pectinately arranged.
               8 All areoles lacking central spines; radial spines whitish to occasionally brown, dense and long so as to obscure the stem epidermis on mature plants [limestone, sandstone, or igneous outcrops]
               8 All areoles lacking central spines or very rarely consistently with 1-4 centrals; radial spines brown to black, stem epidermis easily visible on mature plants; [thornscrub in s. TX over alluvial or sandy, often saline substrate]
             7 Spines not strongly pectinately arranged, more or less porrect.
                 9 Central spines 0-5; [granitic mountains & glades in OK]
          6 Radial spines thick, not bristle-like, (3-) 5-40 (-49) mm long, appressed to widely spreading outward; tepals red.
                   10 Spines microscopically with strongly tuberculate surfaces; [granite & sandstone outcrops around the Llano Uplift of c. TX]
 Echinocereus coccineus ssp. roemeri
                   10 Spines microscopically with finely grooved surfaces; [limestone outcrops in c. TX]
 Echinocereus coccineus ssp. transpecosensis