Consolea spinosissima

Range and identification

POWO gives southern Jamaica as the native range. Older identifications of Cayman Islands plants as C. spinosissima do not automatically document a wider range. Areces-Mallea showed that material from Little Cayman and Cayman Brac belongs to C. millspaughii subsp. caymanensis. [2-WWW] [Areces-Mallea 2001]

Mature segments of C. spinosissima have a conspicuous network of depressions. The 2001 key distinguished the species by an elongated, asymmetric, flattened pericarpel, borne on an oblique, elongated stalk-like part. This differs from the more symmetric, cylindrical structure described in C. moniliformis. The flower together with the stem tissue surrounding the ovary is useful for identification. [Areces-Mallea 2001]

Populacja Hellshire Hills

Strittmatter, Negrón-Ortiz and Hickey described a population in the Hellshire Hills of Jamaica. Of 79 flowering plants, 54 were functionally male, 18 female and seven were described as weak hermaphrodites. Small individuals under 1 m that were not flowering were excluded from the sex-ratio assessment. The result therefore concerns the reproductive part of this population, not all plants of the species. [Strittmatter et al. 2002]

Female flowers had functional ovules, but their anthers did not produce normal pollen. Male flowers produced pollen, while their ovules became nonfunctional before the flower opened. Individuals described as weak hermaphrodites retained a few fertile ovules in some flowers and produced fewer fruits than female plants. This third group did not establish consistent bisexuality throughout the plant. [Strittmatter et al. 2002]

Implications of the later interpretation

In the 2008 comparative study, occasional fertility of the female function in male plants was described as instability of sex expression. Ovules matured from the base towards the top of the ovary. The highest ones could sometimes remain functional until the flower opened, while the others were already degenerating. This explanation connects ovule position, age and chance of fertilisation. [Strittmatter et al. 2008]

Observation of a pollen tube and seed formation documents successive stages of fertilisation, but without a controlled experiment it does not automatically establish where the pollen came from. The studies described therefore did not support a recommendation that any single clone of C. spinosissima would reliably produce seeds after self-pollination. [Strittmatter et al. 2002] [Strittmatter et al. 2008]

Chromosomes and implications for collections

In material from the Hellshire Hills, Negrón-Ortiz found 2n = 66 chromosomes. Plants propagated vegetatively from one individual retain its genetic origin. Collection records therefore benefit from separate documentation of the parent plant, flower function and presence of actual developed seeds, alongside counts of fruit-like structures. [Negrón-Ortiz 2007] [Strittmatter et al. 2002]