Tradescantia subg. Campelia (Rich.) M.Pell., comb. et

Pellegrini, Marco O. O., 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, pp. 11-72: 34

publication ID

http://dx.doi.org/10.3897/phytokeys.89.20388

persistent identifier

http://treatment.plazi.org/id/80859071-C606-AC14-6E8F-668B8BEF223B

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PhytoKeys by Pensoft

scientific name

Tradescantia subg. Campelia (Rich.) M.Pell., comb. et
status

stat. nov.

2.2. Tradescantia subg. Campelia (Rich.) M.Pell., comb. et  stat. nov. Figs 6 P–QView Figure 6, 10View Figure 10

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. 8View Figure 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) 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, EView Figure 10), stamens of different length (Fig. 10 F–HView Figure 10), tapered connective (Fig. 10IView Figure 10), and lateral embryotega; but did not note the zygomorphic calyx (Fig. 10D, EView Figure 10), the shape of the anther sacs, and the white pollen (Fig. 10IView Figure 10), all unusual characters for the genus. The present analysis reveals that important morphological characters, such as the characters listed by Pichon (1946), and previously considered as exclusive to T. sect. Cymbispatha  (sensu Hunt 1980), 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. 10 C–EView Figure 10); flowers with pedicels geniculate at anthesis and pre-anthesis (Fig. 10EView Figure 10), unequal sepals (Fig. 10D, EView Figure 10), dorsal sepal generally keeled (Fig. 10DView Figure 10), outer filaments shorter than the inner (Fig. 10 F–HView Figure 10), white pollen, pistil longer than the stamens (Fig. 10EView Figure 10), and semilateral embryotega.

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Commelinales

Family

Commelinaceae

Genus

Tradescantia

Loc

Tradescantia subg. Campelia (Rich.) M.Pell., comb. et

Pellegrini, Marco O. O. 2017
2017
Loc

Campelia standleyi

Steyerm 1944
1944
Loc

Tradescantia sect. Cymbispatha

C.B.Clarke 1881
1881
Loc

Sarcoperis

Rafinesque 1837
1837
Loc

Sarcoperis bibracteata

Raf 1837
1837
Loc

Zanonia bibracteata

J. Cramer 1803
1803