Tradescantia subg. Campelia
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Ordo: Commelinales
Familia: Commelinaceae
Name
Tradescantia (Rich.) M.Pell., comb. et stat. nov. – Wikispecies link – Pensoft Profile
- Tradescantia sect. Campelia (Rich.) D.R.Hunt, Kew Bull. 41(2): 404. 1986.
- Campelia Rich., Démonstr. Bot.: 46. 1808.
- Zanonia Cramer., Disp. Syst.: 75. 1803, nom. illeg. Type species. Zanonia bibracteata Cramer., nom. illeg. [= Tradescantia zanonia (L.) Sw.].
- Gonatandra Schltdl., Linnaea 24: 659. 1851, Syn. nov. Type species. Gonatandra tradescantioides Schltdl. [= Tradescantia zanonia (L.) Sw.].
- Sarcoperis Raf., Fl. Tellur. 2: 16. 1837, Syn. nov. Type species. Sarcoperis bibracteata (Cramer) Raf. [= Tradescantia zanonia (L.) Sw.].
- Tradescantia sect. Cymbispatha (Pichon) D.R.Hunt, Kew Bull. 35(2): 440. 1980.
- Cymbispatha Pichon, Not. Syst. 12: 224. 1946, Syn. nov. Type species. T. commelinoides Schult.f.
- Tradescantia sect. Rhoeo (Hance) D.R.Hunt, Kew Bull. 41(2): 401. 1986.
- Rhoeo Hance, Ann. Bot. Syst. 3: 659. 1852, Syn. nov. Type species. T. discolor L’Hér. (= T. spathacea Sw.)
- Tradescantia sect. Zebrina (Schnizl.) D.R.Hunt, Kew Bull. 41(2): 404. 1986.
- Zebrina Schnizl., Bot. Zeitung (Berlin) 7: 870. 1849, Syn. nov. Type species. Zebrina pendula Schnizl. (= T. zebrina Heynh. ex Bosse)
- Tradescantia sect. Corinna D.R.Hunt, Kew Bulletin 41(2): 405. 1986, Syn. nov. Type species. Campelia standleyi Steyermark (= T. soconuscana Matuda)
Description
Herbs chamaephytes, rarely geophytes, base definite or indefinite, frequently succulent, terrestrial, rupicolous or epiphytes. Roots thin, fibrous, rarely thick, tuberous. Stems prostrate with ascending apex or erect, herbaceous to succulent, rarely fibrous, little to densely branched, rooting at the basal nodes or at the distal ones when they touch the substrate. Leaves sessile to subpetiolate; distichously or spirally-alternate, evenly distributed along the stem or congested at the apex of the stems; sheaths closed; blades flat to falcate and/or complicate, base symmetrical or asymmetrical, midvein conspicuous, rarely inconspicuous, adaxially impressed, abaxially prominent, rounded, secondary veins conspicuous or inconspicuous. Synflorescences terminal or axillary in the distal portion of the stems, sometimes exclusively axillary, composed of a main florescence with 1–several coflorescences, rarely composed of a solitary main florescence. Inflorescences (main florescences) consisting of a pedunculate double-cincinni fused back to back; inflorescence bract hyaline, tubular, inconspicuous; peduncle bracts present or not, bladeless sheaths, rarely with a reduced leaf-like blade; supernumerary bracts generally present, leaf-like to slightly spathaceous, the same size as the leaves or the cincinni bracts; cincinni bracts spathaceous, similar to unequal to each other, saccate or not, flat or conduplicate, free or fused to each other, overlapping each other or not; bracteoles expanded, imbricate or completely involving the cincinnus, linear-triangular to triangular or flabellate, hyaline. Flowers bisexual, slightly zygomorphic due to the unequal sepals and geniculate pedicels, flat or tubular, when present floral tube infundibuliform to hypocrateriform, rarely campanulate; pedicel gibbous at apex, geniculate at anthesis and pre-anthesis, deflexed at post-anthesis; sepals unequal, free to conate, membranous or chartaceous, rarely fleshy, elliptic to broadly elliptic to obovate, dorsally keeled or not, apex obtuse or acute; petals sessile or clawed, equal, free to conate, blade elliptic to ovate to broadly ovate or rhomboid to broadly obovoid to obovoid, flat, base cuneate to obtuse, margin entire, apex acute to obtuse; stamens 6, arranged in two series, subequal, the outer whorl shorter than the inner, filaments free from the petals or epipetalous, straight at anthesis and post-anthesis, basally, medially or apically sparsely bearded with moniliform hairs, hairs shorter than the stamens, variously colored, anthers with connective cordate to sagittate to linearly-tapered, rarely rhomboid, variously colored, anther sacs round, white, sometimes pink to lilac or yellow, pollen white; ovary white, glabrous or pubescent, locules (1–)2-ovulate, style straight at anthesis and post-anthesis, variously colored, cylindrical at base, cylindrical to obconical at the apex, stigma capitate to trilobate, pistil shorter to the same length to longer than the stamens. Capsules subglobose to globose, light to medium brown when mature, glabrous, loculicidal, 3-valved, sometimes apiculate due to persistent style base. Seeds exarillate, 1–2 per locule, ellipsoid to narrowly trigonal, ventrally flattened, cleft or not towards the embryotega, testa smooth to faintly rugose to rugose or costate with ridges radiating from the embryotega, embryotega semilateral, conspicuous, with a prominent apicule.
Habitat, distribution and ecology
Tradescantia subg. Campelia is the most widespread of the subgenera, ranging from Mexico to Argentina (Fig. 8). It is highly diverse in Central America and northern South America, with its species being mostly restricted to forest understories or growing in elevated open areas, such as the Andean region.
Included species
Tradescantia subg. Campelia is composed by ca. 15 species, including: Tradescantia commelinoides Schult. & Schult.f., T. deficiens Brandegee, T. gracillima Stand., T. grantii Faden, T. huehueteca (Standl. & Steyerm.) D.R.Hunt, T. plusiantha Stand., T. poelliae D.R.Hunt, T. praetermissa M.Pell., T. schippii D.R.Hunt, T. soconuscana Matuda, T. spathacea Sw., T. standleyi Steyerm., T. zanonia (L.) Sw., and T. zebrina Heynh. ex Bosse. Despite its small number of species, a great deal of taxonomic problems and species complexes still prevents the total number of species from being known.
Comments
When Cymbispatha was proposed by Pichon (1946)[1] as a new genus, he reinforced the importance of inflorescence characters in Commelinaceae, especially the shape of the cincinni bracts, and position of the embryotega on the seed. The author characterized his new genus as possessing a double-cincinni subtended by two spathaceous bracts (Fig. 10D, E), stamens of different length (Fig. 10F–H), tapered connective (Fig. 10I), and lateral embryotega; but did not note the zygomorphic calyx (Fig. 10D, E), the shape of the anther sacs, and the white pollen (Fig. 10I), all unusual characters for the genus. The present analysis reveals that important morphological characters, such as the characters listed by Pichon (1946)[1], and previously considered as exclusive to T. sect. Cymbispatha (sensu Hunt 1980[2]), are actually shared with all or most species from the T. subg. Campelia. These characters are: subequal sepals, keeled dorsal sepal, subequal stamens, and semilateral embryotega. Characters like, zygomorphic sepals, and pedicels the same size as the floral buds or sessile to subsessile are not exclusive to T. sect. Cymbispatha, but are actually homoplastic synapomorphies to the two larger clades within the Campelia clade (i.e. T. commelinoides group+T. zebrina group). Spathaceous bracts, the presence of supernumerary bracts, and white pollen grains in vivo, are also recovered in the present analysis as homoplastic synapomorphies to this subgenus. Thus, T. subg. Campelia can be differentiated from the remaining subgenera by synflorescences with one or more coflorescences, presence of peduncle bracts, presence of supernumerary bracts, spathaceous cincinni bracts (Fig. 10C–E); flowers with pedicels geniculate at anthesis and pre-anthesis (Fig. 10E), unequal sepals (Fig. 10D, E), dorsal sepal generally keeled (Fig. 10D), outer filaments shorter than the inner (Fig. 10F–H), white pollen, pistil longer than the stamens (Fig. 10E), and semilateral embryotega.
Taxon Treatment
- Pellegrini, M; 2017: Morphological phylogeny of Tradescantia L. (Commelinaceae) sheds light on a new infrageneric classification for the genus and novelties on the systematics of subtribe Tradescantiinae PhytoKeys, (89): 11-72. doi
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Other References
- ↑ 1.0 1.1 Pichon M (1946) Sur les Commélinacées. Notulae Systematicae. Herbier du Museum de Paris 12(3–4): 217–242.
- ↑ Hunt D (1980) Sections and series in Tradescantia. In: American Commelinaceae, vol. IX. Kew Bull. 35(2): 437–422. https://doi.org/10.2307/4114596
