Dyckia selloa (Koch, 1873) Baker, 1889
publication ID |
https://doi.org/ 10.11646/phytotaxa.595.2.4 |
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https://doi.org/10.5281/zenodo.7908730 |
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https://treatment.plazi.org/id/FB6AEA65-FF99-FFC9-22F0-F9A2E76DFB66 |
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Plazi |
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Dyckia selloa |
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1. Dyckia selloa complex
Herbs rhizomatous or acaulescent. Inflorescence axillary, rarely simple ( D. delicata ), generally composed of first to third order, rarely up to fourth order branches ( D. nigrospinulata ); peduncle bracts foliaceous; first order branches numerous, usually more than 10, spirally arranged along the main axis of the fertile part, occupying ca. 2/3 or more of the fertile portion of inflorescence; second order branches when present usually less than 5, distichous (rarely polystichous as in D. nigrospinulata ) at the base of the first order branches; third order branches when present usually underdeveloped at the base of the second order branches, with few or no flowers; floral bracts usually triangular, reduced, shorter than the sepals. Flowers numerous (more than 100), androgynosporangiate, protandric, sessile or pedicellate; hypanthium absent or reduced; corolla tubular to rarely campanulate ( D. rigida ) at anthesis; petals oblong or oblanceolate, not unguiculate, generally abaxially indumented or with trichomes only along the margins (rarely glabrescent as in D. selloa and D. myriostachya ); stamens reaching the apex of the petals or exserted; filaments free or inconspicuously connate at the base, the antepetalous ones briefly adnate to the petals or free; anthers generally rostrate at the apex; locules with less than 18 ovules; ovules generally suberectly positioned in relation to the longitudinal axis of the ovary, disposed in two rows per locule (rarely four as in D. delicata and D. agudensis ); stigma at anthesis usually with erect to suberect stigmatic lobes, reaching the apex of the petals or exserted. Seeds oblanceoloid with tegument equally distributed in raphe and antiraphe, chalaza slightly expanded and asymmetrical or as developed as the raphe and the antiraphe.
Species: —The species that possess these morphological characteristics and form this complex are: D. agudensis Irgang & Sobral (1987: 5) , D. alba Winkler (1982: 33) , D. delicata Larocca & Sobral (2002: 234) , D. hebdingii Smith (1971: 90) , D. magnifica sp. nov. (described here), D. maritima Baker (1889: 136) , D. myriostachya Baker (1889: 137) , D. nigrospinulata Strehl (2008: 9) , D. pseudodelicata B̧neker & Mariath (2022: 60), D. retardata Winkler (1982: 42) , D. retroflexa Winkler (1982: 44) , D. rigida Strehl (2004: 32) , D. selloa ( Koch 1873: 7) Baker (1889: 136) , and D. tomentosa Mez (1896: 515) .
Observations: —The D. selloa complex is characterized and basically distinct form other species of Dyckia s.s. by the following set of characters: inflorescences usually composed of first to third order (vs. simple or compound to first order), with numerous first order branches (usually more than 10 vs. less than 10 branches), generally small and inconspicuous floral bracts, numerous flowers (more than 100 vs. less than 80) with non-unguiculate (vs. usually unguiculate) petals, stigma at anthesis usually with erect to suberect (vs. twisted) stigmatic lobes, pauciovulate ovary locules (less than 18 vs. more than 30 ovules) and oblanceoloid (vs. flattened) seeds with a poorly developed wing.
Mez (1896, 1935) presents as main diagnostic character of Prionophyllum the dimorphic flowers, the larger ones would be hermaphrodites and the smaller ones with reduced androecium. This is reproduced in several taxonomic treatments (e.g. Smith & Downs 1974; Krapp & Eggli 2019). However, we never checked specimens with really dimorphic flowers. We found some flowers galled by insects in D. selloa specimens, that generated anomalies in the size of flowers and floral parts, and we suspect that this may be related to what Mez reported. Koch (1874: 7), when describing Prionophyllum selloum Koch (1873: 7) as a new monospecific genus, describes “hermaphrodite” flowers and points out that the habit resembles Dasylirion Zuccarini (1838: 258) (Dracaenaceae) and Hechtia Klotzsch (1835: 401) ( Bromeliaceae , Hechtioideae ), but differs greatly by its hermaphrodite flowers (“ Planta Dasylirii et Hechtiae specierum habitum prae se fert, sed floribus hermaphroditis longe difert. ”).
Krapp & Eggli (2019) include D. racinae Smith (1988: 249) in this complex, however, this taxon does not possess several of the diagnostic characteristics mentioned above (e.g. petals oblong to oblanceolate, not unguiculate, and seeds oblanceoloid). B̧neker et al. (2020, 2021) regard the taxon as D. × racinae , arguing that there are strong indications that this taxon may be a natural hybrid between D. selloa and D. dusenii Smith (1932: 98) and therefore has similarity with the species of the D. selloa complex. Here we do not consider D. × racinae as belonging to this complex.
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