Habit, roots and two segment types
Plants form spreading mats reaching about a metre wide or more, with a fibrous root system. Main segments are 50–121 mm long and 30–46 mm wide in the description. They remain firmly joined, building compact branches. Smaller propagation segments, 30–50 mm long, with weaker junctions may form at their ends. [Donati 2018]
Sparsely arranged areoles produce 6–10 central and 6–8 marginal spines. Central spines reach about 55 mm long, with an angular cross-section, expanded base and wrinkled surface. Variation in grey, whitish and brown shades accompanies a distinct spine structure. Young growth has rapidly shed leaves. [Donati 2018]
Flowers, fruits and phenology
Flowers reach 48–64 mm, with a pale yellow perianth, greenish base, green staminal filaments and 5–7 yellow stigma lobes. The pericarpel is elongated. Fruits 40–75 mm long gradually dry after ripening, and seeds are about 4–5 mm. At the sites studied, flowering was observed from mid-May to July, with fruiting from September. [Donati 2018]
Saline desert depressions
The description comes from El Sobaco and southern El Hundido in Coahuila. Plants occupy flat alluvial substrates containing salts and gypsum, periodically flooded after rain and then drying rapidly. A dark biological crust covers the surface locally. G. moelleri, occurring in the same region, also occupies other microhabitats on clay-gypsum substrate. [Donati 2018]
Identification and chromosome number
In the comparative study, G. halophila was larger than G. moelleri and had a longer pericarpel. The comparison presents means of the sample examined. Trait ranges of individual plants partly overlap. Identification was based on a combined comparison of architecture, areoles, flowers, habitat and cytology. [Donati 2018]
| Cecha | G. halophila | G. moelleri |
|---|---|---|
| Plant width [cm] | 55,46 ± 1,22 | 29,12 ± 0,73 |
| Segment length [mm] | 73,58 ± 2,05 | 41,00 ± 0,90 |
| Segment width [mm] | 35,48 ± 0,33 | 25,32 ± 0,32 |
| Main spine length [mm] | 30,28 ± 0,78 | 27,02 ± 0,49 |
| Pericarpel length [mm] | 58,42 ± 0,44 | 33,74 ± 0,41 |
Reproduction and cytological variation
Root-tip samples showed 2n = 44, tetraploidy, in the G. halophila examined and 2n = 22 in G. moelleri. Both levels were found among selected plants with intermediate appearance. The author considered the significance of the ploidy difference for reproductive isolation, with a limited number of individuals examined. [Donati 2018]
Observations beneath plants documented detached and rooted segments, with greater vegetative regeneration in G. halophila than in G. moelleri. The index reported in the paper denotes rooted propagules per plant examined. It separates the field outcome from the laboratory rooting capacity of an individual cutting. [Donati 2018]
Synonyms and names in the literature
Corynopuntia halophila [2-WWW]