Turbinicarpus laui

Name and range

Turbinicarpus laui is an accepted species with a natural range in northeastern Mexico reaching Jalisco. Neolloydia laui and Pediocactus laui are synonyms. The current database includes a broader area than the origin of the single batch used in the microscopic study. [2-WWW]

The spine analysis used plants raised from seeds TCG 11003, originating from Mezquite Grande in San Luis Potosí. The author maintained a documented collection and compared plant appearance with taxonomic descriptions. The results refer to this material. [Mosco 2009, p. 120–121, tab. 1]

Szczeciniaste ciernie

Radial spines had a bristle-like texture and continuous epidermis whose cells formed feathery projections. Their outer surface differed from the smooth one in T. lophophoroides and the short protrusions in T. pseudopectinatus. Internal fibres had thinner walls than those of many hard spines in other taxa compared. [Mosco 2009, p. 121–123, tab. 2]

Mosco linked the bristle-like form to the combination of a thin overall spine and relatively weakly thickened fibre walls. This explains the delicate appearance through tissue organisation. The feathery relief itself also occurred in kadenicarpi then described as Turbinicarpus pseudomacrochele. The surface feature therefore appears in more than one lineage of the historical genus. [Mosco 2009, Mosco, pp. 121–127. Vázquez-Sánchez et al., p. 412] [Vázquez-Sánchez et al. 2019, Mosco, pp. 121–127. Vázquez-Sánchez et al., p. 412]

Place in the current genus

In the analysis of DNA and structural traits, T. laui belonged to Turbinicarpus in the narrow, current treatment. Some relationships among species within this lineage remained poorly resolved. Justification of genus boundaries rested on a larger dataset than a single spine type. [Vázquez-Sánchez et al. 2019, p. 409–414]

Anatomical comparison of stems in this lineage described prismatic crystals in the hypodermis and fibre-free wood with wide-band tracheids. Taxonomic conclusions were based on tissue traits together with molecular data. The plant's external smallness therefore combines with structure typical of the lineage studied, alongside substantial variation in spine micromorphology. [De la Rosa-Tilapa et al. 2019, De la Rosa-Tilapa et al., online version, pp. 2–4. Vázquez-Sánchez et al., p. 412] [Vázquez-Sánchez et al. 2019, De la Rosa-Tilapa et al., online version, pp. 2–4. Vázquez-Sánchez et al., p. 412]

Regeneration from seedling fragments

Mata Rosas and colleagues obtained adventitious shoots from longitudinally split T. laui seedlings in vitro. The abstract describes the effects of benzyladenine and naphthaleneacetic acid, shoot rooting on diluted MS medium and greenhouse acclimatisation. These are separate developmental stages of laboratory-produced material. [Mata Rosas et al. 2001, abstract]

An adventitious shoot develops somewhere other than an existing shoot tip. Regeneration from a seedling fragment allows new shoots to be obtained from a limited amount of starting material. Transfer to a substrate still requires rooting and adjustment to greenhouse conditions. The available abstract confirms that these stages were conducted, without a complete set of conditions and sample sizes. [Mata Rosas et al. 2001, abstract]

An interspecific hybrid

Turbinicarpus × mombergeri is the hybrid of T. laui × T. pseudopectinatus accepted in POWO. A 2022 publication describes development of its shoot cultures. Hyperhydricity and shoot quality are explored in a separate article. Results for the hybrid concern the material studied, originating from both parents. [2-WWW] [Santos-Díaz et al. 2022, POWO, formula. Santos-Díaz et al., abstract]

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