Echinocerteus posselgeri
(Synonym: Wilcoxia poselgeri)

E. poselgeri (SB852 Jim Hogg Co, Texas, USA) has bright pink flowers, and makes a spectacular sight and an interesting addition to any collection.
 

Tall  pencil-thin stem arising
from a tuberous root system

Morphology (Identifying Characteristics):
Habit: Shrubby, scarcely branched, initially erect, later sprawling or clambering.
Stem: Very tall and slender, dark coloured. up to 1.2 m, diameter 2 cm, ribs 6-10
Spines: tan-greyish white; 1 central up to 9 mm long, enlarged at its base, 4mm long; 8-15 straight radials, 4,5mm long, closely appressed (except at the stem tip)
Roots:  tuberlike, Contrarily to E. kroenleinii, the underground storage organ similar to dahlia tubers is not capable of producing new shoots. Those sprout out  only from the main cut stem. Each plant can have up to 8 tubers, 10-20 mm in diameter, with a length of 60-100 mm. The colour is light brown in youth, later brown.
Flower: Pink Rose/Mauve Magenta (Pink-Purple)
Fruit: Ovoidal 20 mm Long, 10-15 mm Ø, dark green to brownish, pulp white
Seeds: Black 1,5mm
Phenology: Blossoming time: Late Spring/Early Summer

Notes: It apparently looks like some Peniocereus species. However the flowers, fruits, and seeds of E. poselgeri are characteristic for Echinocereus, somewhat comparable to those of E. reichenbachii.

Cultivation:  Do not over water. They need to be kept in a cool, dry place during winter rest (at -5 +10°C).   This is important for the flowers as well as for their health. Without this cool winter period they normally won't get any buds.  It  is quite frost hardy -7 (-10)° C.
Sun Exposure: Best in full or partial sun exposure.

Photo of conspecific taxa, varieties, forms and cultivars of plants belonging to the Echinocereus posselgeri complex (This Taxon has lots of synonyms ( like many other cacti) whit several controversial varieties and subspecies and comprises different forms):

• Echinocereus kroenleinii
• Echinocereus leucanthus
• Echinocereus posselgeri
• Echinocereus waldeisii (E. tamaulipensis ssp. waldeisii)

Scientific Name: Echinocereus poselgeri Lemaire 1868  Published in: Cactées. 57. 1868 Table 2  fig. 2

Conservation status: Listed in CITES Appendix II

Section: Wilcoxia

Distribution: West & South West USA (Texas) and Mexico (Coahuila, Nuevo Leon, Tamaulipas)

Habitat: Among thorn scrub in alluvial soils; 0-200 m;
 

Locus typicus: USA: Texas, near the Rio Grande, H. POSELGER

Type: Lectotypus (L. BENS0N 14 , 1982): USA: Texas, Rio Grande'aboy*Belleville, H. POSELGER coll. 1850 [MO]

Synonyms:

• Cereus tuberosas Poselger.
  Allg.Gartenz. 21: 135, 1853 nom. illegit.
• Echinocereus tuberosus (H. Poselger) T.  Ruempler
  in FÖRSTER 's Handb. Cacteenk‑,ed. 2: 783, 1886
• Wilcoxia tuberosa (H. Poselger) K. Kreuzinger
  Verzeichnis: 18, 1935
• Cereus poselgeri (Ch. Lemaire) J. M. Coulter.
  Contr.U.S. NAT.Herb. 3: 398, 1896
• Wilcoxia  poselgeri (Ch. Lemaire) N. L. Britton & J. N. Rose.
  Contr.U.S. Nat. Herb. 12: 434, 1896

Vernacular name (s): Sacasil,  Zocoxochitl Pencil cactus, Dahlia hedgehog cactus.

Buds just before opening

Green stigma and yellow  anthers

Some photos and information in this page courteously provided by Dieter & Irene Waldeis