Thelocactus bicolor var. bicolor

Illustrated
Synonyms: Thelocactus bicolor var. schottii (K. Schumann) F. M. Knuth Thelocactus bicolor var. tricolor
Treatment appears in FNA Volume 4. Treatment on page 218. Mentioned on page 215.

Plants few branched or unbranched, usually not deep-seated in substrate. Stems usually ovoid to cylindric at maturity, 7.5–18 (–38) × 5–10 (–13) cm, surface very poorly concealed to 1/2 hidden by spines; ribs 8–13, tubercles confluent into rounded ribs 15–25 mm wide; areoles spaced 8–20 mm apart along ribs. Spines red-and-white (older spines weather to ashy white); radial spines 9–18 per areole, longest spines 12–30 mm; adaxial (bladelike) spines 16–75 (–100) × 1.5 mm; central spines (1–) 4, longest spines terete to sharply angular, then abaxially keeled and adaxially flat to grooved, (13–) 20–45 (–60) × 0.4–1.5 mm, adaxial 3 like radials but larger. 2n = 22.


Phenology: Flowering (Feb–May)Jul–Sep.
Habitat: Chihuahuan desert scrub, Tamaulipan thorn scrub, sedimentary, igneous, and alluvial substrates
Elevation: 0-1200[-2000] m

Distribution

V4 407-distribution-map.gif

Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (Nuevo León), Mexico (San Luis Potosí), Mexico (Tamaulipas), Mexico (Zacatecas)

Discussion

Thelocactus bicolor var. bicolor, in the strict sense, may be limited to Mexico; if so, then var. tricolor and/or var. schottii might deserve formal recognition.

Selected References

None.

Lower Taxa

None.
7.5 cm75 mm <br />0.075 m <br /> (10 cm100 mm <br />0.1 m <br />) +
16mm +  and 75mm +
1.5 cm15 mm <br />0.015 m <br /> (?) +
cushionlike +
apart +  and spaced +
circular to linear +
2 cm20 mm <br />0.02 m <br /> (5.2 cm52 mm <br />0.052 m <br />) +
deciduous +  and persistent +
hourglass--shaped +
0.8 cm8 mm <br />0.008 m <br /> (2 cm20 mm <br />0.02 m <br />) +
Allan D. Zimmerman +  and Bruce D. Parfitt +
(Galeotti ex Pfeiffer) Britton & Rose +
hardened +
Echinocactus bicolor +
triangular +
4.2 cm42 mm <br />0.042 m <br /> (5.8 cm58 mm <br />0.058 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
curved +  and straight +
13mm +  and 42mm +
angled +, flattened +  and terete +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
proliferating +
flattened +  and cylindric +
not mucilaginous +
notched +
Tex. +, Mexico (Chihuahua) +, Mexico (Coahuila) +, Mexico (Durango) +, Mexico (Nuevo León) +, Mexico (San Luis Potosí) +, Mexico (Tamaulipas) +  and Mexico (Zacatecas) +
0-1200[-2000] m +
not separating +
15 cm150 mm <br />0.15 m <br /> (30 cm300 mm <br />0.3 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (15 cm150 mm <br />0.15 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1.2 cm12 mm <br />0.012 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
green;brownish purple +
persistent +, long +  and deciduous +
7mm;18mm +
spheric +  and short cylindric +
not juicy +
0.6 cm6 mm <br />0.006 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
conspicuous +
Chihuahuan desert scrub, Tamaulipan thorn scrub, sedimentary, igneous, and alluvial substrates +
2.8 cm28 mm <br />0.028 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
deciduous +  and persistent +
rudimentary +
flat +  and terete +
nearly +  and microscopic +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
tuberculate +
fluted;spheric;depressed-spheric or club-shaped +
4.5 cm45 mm <br />0.045 m <br /> (6 cm60 mm <br />0.06 m <br />) +
20mm +  and 45mm +
1.2 cm12 mm <br />0.012 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
fringed +  and denticulate +
deciduous +  and persistent +
Flowering (Feb–May)Jul–Sep. +
not mucilaginous +
older +  and young +
ridgelike +  and nipple--shaped +
Bull. Torrey Bot. Clu b +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
tuberculate +
rounded +
15mm;25mm +
5 +  and 21 +
triangular +
arillate +  and strophiolate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
papillate +
cylindric;pyriform +
constricted +
0.1 cm1 mm <br />0.001 m <br /> (0.175 cm1.75 mm <br />0.00175 m <br />) +
Illustrated +
3.5 cm35 mm <br />0.035 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
7.5 cm75 mm <br />0.075 m <br /> (10 cm100 mm <br />0.1 m <br />) +
red-and-white +
straight +
deciduous +  and persistent +
9mm +  and 35mm +
9 (?) +  and 18 (?) +
ribbonlike +, bladelike +  and flattened +
1.6 cm16 mm <br />0.016 m <br /> (7.5 cm75 mm <br />0.075 m <br />) +
hard +  and rigid +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0-4 times wider than thick +
decurrent +
8 cm80 mm <br />0.08 m <br /> (10 cm100 mm <br />0.1 m <br />) +
6.5 cm65 mm <br />0.065 m <br /> (10 cm100 mm <br />0.1 m <br />) +
4 cm40 mm <br />0.04 m <br /> (8 cm80 mm <br />0.08 m <br />) +
4 cm40 mm <br />0.04 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
unsegmented +
10 cm100 mm <br />0.1 m <br /> (18 cm180 mm <br />0.18 m <br />) +
3cm;38cm +
usually ovoid +  and cylindric +
succulent +
4cm;10cm +
reddish +  and red-orange or pale reddish-brown or yellowish +
18 cm180 mm <br />0.18 m <br /> (38 cm380 mm <br />0.38 m <br />) +
10 cm100 mm <br />0.1 m <br /> (13 cm130 mm <br />0.13 m <br />) +
7.5 cm75 mm <br />0.075 m <br /> (18 cm180 mm <br />0.18 m <br />) +
tuberculate +
5 cm50 mm <br />0.05 m <br /> (10 cm100 mm <br />0.1 m <br />) +
Thelocactus bicolor var. schottii +  and Thelocactus bicolor var. tricolor +
adventitious +
tuberlike +
epipetric +  and epiphytic +
Thelocactus bicolor var. bicolor +
Thelocactus bicolor +
variety +
dull +  and glossy +
compressed +, pyramidal +, conic +  and rounded +
unbranched +, branched +  and few +
epiphytic;epiphytic;epiphytic +
barrel-shaped +  and spheric +