Senecio series Culcitium (Bonpland) Cabrera, 1985
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publication ID |
https://doi.org/ 10.11646/phytotaxa.340.1.1 |
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persistent identifier |
https://treatment.plazi.org/id/D605E214-2747-FFEE-FF68-3BA66967A731 |
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treatment provided by |
Felipe |
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scientific name |
Senecio series Culcitium |
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Morphology of Senecio series Culcitium
Habit. Perennial, mostly scapiform or acaule rosulate ( Senecio expansus and S. hyoseridis ) herbs, from 6–9 cm ( Senecio cajonensis , S. ferrugineus ) to more than 1 m tall (e.g. 0.45–1.5 m Senecio canescens , 0.4– 1 m S. mojandensis ). Some species originally described under Lasiocephalus or Aetheolaena are scandent subshrubs up to 3 m tall, growing on other plants (e.g. Senecio campanulatus , S. cuencanus , S. involucratus , S. otophorus , S. patens , and S. subinvolucratus ) ( Fig. 1 View FIGURE 1 ).
Stems. The stems of most species are single (rarely basally branched, e.g. Senecio lingulatus , S. longepenicillatus , S. superparamensis ), ribbed, and flexuose in scandent species (e.g. S. campanulatus , S. patens ). They are unifomly leafy (e.g. Senecio imbaburensis and S. superandinus ), densely leafy at the base and scapiform in the upper part (e.g. S. cocuyanus , S. nivalis ), or densely leafy towards the apex (e.g. S. rhizomatus ) ( Fig. 1 View FIGURE 1 ).
Pubescence. Typical pubescence consists of long uniseriate aseptate flagellate trichomes ( Fig. 2 View FIGURE 2 ). This type of trichome is composed of one or two foot cells, one-two (three)-celled stalks or stipes, and a single very long, flagellate, aseptate apical cell. This basic trichome type is present on stems, leaves, and phyllaries.The thickness of the pubescence on leaves is often variable, ranging from tight to loose wool even in the same species (e.g. Senecio keshua ). Glandular trichomes can be found (e.g. Senecio rhizomatus ).
Leaves. Mostly entire (pinnatipartite in Senecio hyoseridis ), margins crenate ( S. expansus ), serrulate (i.e. S. serratifolius , S.violaefolius ),dentate or denticulate(e.g. S.campanulatus , candollei , S.involucratus , S.longepenicillatus , S. mojandensis , S. patens , S. praeruptorum , S. theprosioides ); sessile (e.g. S. josei , S. lingulatus ), petiolate (e.g. S. involucratus , S. longepenicillatus , S. mojandensis , S. praeruptorum , S. superparamensis ) or more commonly attenuate into a pseudopetiole.
Capitulescences. Capitula are solitary or 2–30, arranged in a corymbiform cymose capitulescence. Although the number of capitula is variable, Cuatrecasas (1951) attempted to use this feature to separate infraspecific level taxa within S. canescens , i.e. var. monocephalum Wedd. ; var. boyacensis ; var. macrocephalus Cuatrec. ; var. ecuadoriensis Cuatrec. ; var. elongatus Cuatrec. ; f. magnificus Cuatrec. , all with a similar geographical distribution. Nevertheless, in the present treatment as well as in Hind (2011), all of Cuatrecasas’s infraspecific taxa are not recognised in Senecio canescens .
Capitula. The capitula of all the species are discoid and nodding (except S. expansus and S. hyoseridis with sessile capitula).
Involucres. Campanulate or hemispherical involucres are characteristic of all species, with uniseriate phyllaries and one or more series of calycular bracts. In most species the calyculus can be easily distinguished from the phyllaries, but it is poorly differentiated in S. canescens , S. cocuyanus , S. hypsobates , S. keshua , S. nivalis , S. serratifolius , S. superandinus , and S. superparamensis .
Corollas. The corollas are tubular, 5-lobed, with lobes generally acute ranging from 0.5 to 2 mm long. Aetheolaena was characterized by having dirty white to greenish-yellow corollas and yellow corolla, or yellow creams corollas were mentioned for Lasiocephalus and Culcitium , respectively ( Nordenstam 2007). However, this is a variable feature throughout the range of S. series Culcitium . In fact, they can be yellowish (e.g. S. cajonensis , S. candollei , S. canescens , S. cocuyanus , S. diemii , S. expansus , S. ferrugineus , S. hypsobates , S. imbaburensis , S. keshua , S. leucophorbius , S. nivalis , S. patens , S. hyoseridis , S. serratifolius and S. superandinus ), or greenish yellow (e.g. S. campanulatus , S. cuencanus , S. gargantanus , S. involucratus , S. lingulatus , S. longepenicillatus , S. mojandensis , S. otophorus , S. subinvolucratus , S. josei and S. superparamensis ).
Style Arms. All forty three species have style arms truncate or convex, with an apical (sometimes incomplete) crown of papillae ( Fig. 3 A View FIGURE 3 ). Only the species previously assigned to Aetheolaena or Lasiocephalus , i.e. S. campanulatus , S. cuencanus , S. decipiens , S. doryphyllus , S. gargantanus , S. imbaburensis , S. involucratus , S. lingulatus , S. longepenicillatus , S. mojandensis , S. otophorus , S. patens , S. pindilicensis , S. subinvolucratus , S. superandinus , and S. cocuyanus , S. josei , S. piedrahitae and S. superparamensis have penicillate apex or tuft ( Fig. 3 B–C View FIGURE 3 ).
Stamens. As in most South American species of Senecio s.str. ( Salomón et al. 2016), all species of S. ser. Culcitium have basally auriculate anthers, with ovate or oblong apical anther appendages, whereas the filament collar of the stamens is usually balusterform (only cylindrical in S. burkartii ).
Pollen. The pollen grains are tricolporate, oblate spheroidal to prolate spheroidal in equatorial view, radially symmetrical and isopolar (terminology according to Erdtman 1969). The sculpture of the grains ( Salomón et al. 2016) is principally microechinate with spinules 1–3 μm long ( Fig. 4 View FIGURE 4 ).
Achenes. All species have glabrous achenes with 10 vascular bundles.
Carpopodium. The carpopodium is differentiated, annular in all species of S. ser. Culcitium .
Pappus. In all species the pappus bristles are barbellate, white and persistent.
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