Cryptanthus Key by Marcelo de Senna Dias Candido for 43 species in Bromelia Vol2 #4 1995 and amended by Butcher to 59 species as at 2/2003
C. acaulis has been moved because of Luther's findings but C. bromelioides stays in the same relative position despite the fact that the revised description in Ramirez 1998 shows floral bracts as flat not carinate

1. Petals Free tip suborbiculate, Stigma with almost connate, straight lobes 2
Spatulate, apex acute to subacute, Stigma with free recurving lobes 16
2. Plant Distinctly caulescent 3
Stemless or shortly caulescent 5
3. Leaves With undulate margins, 1.5 to 2 cm wide 6
With straight margins 4
4. Leaves Soft, Plant suggesting Pitcairnia (Domingos Martins, ES) caulescens
Stiff, 15 -35cm long 5
Stiff, to 7cm long, strongly spined (ES) microglazioui
5. Leaves 0.7-1.2 cm wide and up to 15 cm long, sepals joined for 3-4mm (Santa Barbara, MG) glazioui
With straight margins, 0.8 - 1cm wide, 20-35cm long, sepals free (Domingos Martins ES) fernseeoides
6. Leaf blade Up to 30 cm long (Santa Leopoldina, ES) exaltatus
5-12 cm long 6a
6a. Leaf blade 1.5cm wide, 7 fascicles, sepals connate 7 - 7mm (Santa Leopoldina, ES). pseudoglaziovii
2cm wide, 10 fascicles, sepals connate 2mm (Domingos Martins ES) leuzingerae
7. Leaves Glabrous to glabrescent adaxially 8
Densely lepidote on both sides 13
8. Leaves Bearing distinct dark-brown crossbands abaxially (Domingos Martins, ES) roberto-kautskyi
Evenly lepidote abaxially, without any crossbands 9
9. Leaf blade Lanceolate to broadly lanceolate 10
Narrow, linear-lanceolate 11
10. Leaf blade ca. 2,5 cm wide. (Domingos Martins, ES) pseudoscaposus
5-7 cm wide (Guarapari, ES) latifolius
3.5-5.5cm wide at 2/3rds length, petals green (Vitoria ES) grazielae
11. Leaf margins Distinctly undulate (Santa Leopoldina, ES) odoratissimus
Straight 12
12. Leaf spines 1mm long. (Domingos Martins, ES) scaposus
Acicular, 2-3 mrn long. (Minas Gerais) schwackeanus
13. Leaf spines 0.5 mm long. (Domingos Martins, ES) whitmanii
Over 1mm in length 14
14. Leaf spines Retrorse (Diamantina, MG) warasii
Dentate, or with acicular spines 15
15. Leaves Nervate abaxially, margins with acicular spines.(Santa Barbara, MG) caracensis
Not distinctly nervate abaxially, margins with dentate-triangulate spines (Diamantina, MG) leopoldo-horstii
16. Leaves Striped adaxially 17
Without stripes adaxially 28
17. Leaves With lepidote crossbands adaxially 18
With stripes longitudinal 20
18. Sepals Serrulate (S. Bento, PE) fosterianus
Entire 19
19. Plant Propagating by axillary shoots, never stoloniferous (Recife, PE) zonatus
Stoloniferous, stolons 10-20 cm long (Gravata, PE) burle-marxii
20. Stripe Single, median, pale colored 21
Stripes 2 or more 26
21. Sepals Serrulate (Itabirito, MG) minarum
Entire 22
22. Leaf margins Mostly entire, serrulate near the apex only (Marau, BA) ruthiae
Serrulate throughout 23
23. Leaf blade Glabrous adaxially 24
Not totally glabrous 25
24. Leaf blades 2-3cm wide, 24cm long, Sepals 4mm long (Ubaira BA) ubairensis
To 2cm wide, 17cm long, Sepal 11mm long (ES) praetextus
25. Leaf blade Lepidote to glabrescent adaxially (Sao Lourenco da Mata, PE) pickelii
Lepidote near base, glabrous to apex (Caete - Acu BA) diamantinensis
26. Leaf blade Glabrous adaxially bivittatus
Partially lepidote adaxially 27
27. Trichomes On leafbase only (Santa Teresa, ES) marginatus
Arranged in three longitudinal stripes lacerdae
28. Leaves With contrasting color and indumentum above and below 29
Densely lepidote on both sides 45
29. Leaves Distinctly petiolate 29a
Not petiolate 30
29a. Petioles Distinctly terete (tubular) ( Vitoria ES) teretifolius
Only channelled 29b
29b. Leaves Broadly lance-ovate, 4-5cm wide, blotched or uniformly green adaxially (ES) beuckeri
Linear lanceolate, to 2cm wide (Jaguaripe BA) lyman-smithii
30. Floral bracts (Hermaphroditic! or outer fascicles) shorter than the ovary 31
(Hermaphroditic! or outer fascicles) equal to exceeding the ovary 32
31. Plant Caulescent, leaf blade minutely and densely serrulate, spines less than 0.5 mm long (Domingos Martins, ES) correia-araujoi
Stemless, leaf blades serrulate, spines 1 mrn long (Vitoria, ES) incrassatus
32. Floral bracts Outer fascicle carinate 33
Outer fascicle ecarinate 42
33. Leaves Not constricted between blade and sheath 34
Distinctly narrowed between blade and sheath 36
34. Leaves 20-45cm long, 2-4cm wide 35
45-80cm long, 1-2cm wide, plant to 80cm tall (Amarelo ES) lutherianus
35. Petals Acuminate (Milagres, BA) seidelianus
With rounded apex (Serra, ES) coriaceus
36. Leaf blade 50-75 cm long 37
30-40cm long (Palmeiras, BA) arelii
Up to 30 cm long 38
37. Petals Bearing two well developed calluses at base(Aracruz,ES) capitatus
Bearing two inconspicuous calluses at base (Paripuera, AL) alagoanus
Without calluses (Una, BA) pseudopetiolatus
38. Sepals Connate at base only osiris
Connate to half their length or more 39
39. Leaf margins Entire at apex delicatus
Entirely serrulate 40
40. Fascicles With 4-6 flowers, leaf margins minutely serrulate (Rio de Janeiro, RJ) bromelioides
With 3 flowers. 41
41. Petals With calluses at base 41a
Without calluses at base 41b
41a. Petals Bearing small calluses at base (Itaberaba, EA) warren-loosei
Bearing large calluses at base (Itapetinga, BA) bibarrensis
41b. Petals White (Pres. Kennedy, ES) dorothyae
White with green tip (Itapetinga, BA) reisii
42. Plant Caulescent, stem to 40cm x 10-15mm diam, leaves up to 40 cm x 12-20mm, canaliculate (Bahia) bahianus
Caulescent, stem to 35cm x 20-30mm diam, leaves up to 46cm x 15-16mm, (San Luzia do Itanhi, SE) sergipensis
Stemless or shortly caulescent 43
43. Leaves Mostly erect, linear-lanceolate (Vitoria, ES) maritimus
Recurvate 44
44. Leaf blades ca. 1.2 cm wide (Potiragua, EA) colnagoi
2-3 cm wide Flowers ca. 2.3 cm long, sepals serrulate or rarely entire (Rio de Janeiro,RJ) sinuosus
45. Plant Caulescent 46
Stemless, leaves over 15cm long 47
Stemless, leaves to 10cm long (Rio de Janeiro RJ) acaulis
46. Sepals Connate to half their length or more diversifolius
Connate near the base only (Una, BA) vexatus
47. Floral bracts Entire or nearly so (Santa Cruz da Vitoria BA) argyrophyllus
Serrulate (Ceres GO) dianae