Cuatrecasanthus H. Rob., Revista Acad. Colomb. Ci. Exact. 17(65): 209 (1989).
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https://dx.doi.org/10.3897/phytokeys.14.2520 |
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persistent identifier |
https://treatment.plazi.org/id/53B33120-11D1-5547-8752-6D027B62E3A9 |
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scientific name |
Cuatrecasanthus H. Rob., Revista Acad. Colomb. Ci. Exact. 17(65): 209 (1989). |
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Cuatrecasanthus H. Rob., Revista Acad. Colomb. Ci. Exact. 17(65): 209 (1989).
Type species:
Vernonia sandemanii H. Rob. & B. Kahn (= Cuatrecasanthus sandemanii (H. Rob. & B. Kahn)H. Rob.)
Description.
Erect branching shrubs, scrambling shrubs or trees (rarely vines) to 3.5 m tall; stems terete, striate, minutely pilose (pilosulous) with evanescent simple hairs or thinly tomentose; pith solid. Leaves alternate, petiolate; blades elliptical or lanceolate, base narrowly cuneate to attenuate, subchartaceous, margins entire to remotely subserrulate, narrowly recurved, apex usually sharply acuminate, adaxial surfaces pilosulous with simple non-septate, thick-walled trichomes, with numerous glandular dots, abaxial surfaces covered with thin whitish tomentum of prostrate myceliiform minutely branching trichomes; secondary veins 4-9 on each side of midvein, ascending basally at 45-60° angles. Inflorescence terminal on leafy stems, rounded corymbiform, branching alternate, with large foliaceous bracts only at lower primary nodes. Heads clustered and sessile in glomerules at ends of short branchlets ( Figs 7C View Figure 7 , 9B View Figure 9 ), individual heads cylindrical; involucral bracts ca. 15 in 5-6 gradate series ( Figs 7D View Figure 7 , 9C View Figure 9 ), inner bracts easily deciduous, outer bracts persistent; receptacle glabrous. Florets one per head; corollas lavender, outside minutely gland-dotted, distally sometimes pilosulous, basal tube narrow, ca. 2.5-4.0 mm long, throat lacking, lobes 5, linear, separated to base of limb, with somewhat thickened margins, not or scarcely distorted on drying ( Figs 7E View Figure 7 , 9D View Figure 9 ); anther thecae purple, with short papillose-fimbriate basal appendage, apical appendage ovate-oblong, ca. 0.5 mm long, glabrous; style base with stopper-shaped node, with thick-walled cells, sweeping hairs non-septate, obtuse to short-acute. Achenes prismatic, 10-costate ( Figs 7G View Figure 7 , 9F View Figure 9 ), surface sometimes fleshy, with numerous glandular dots, with few or no eglandular trichomes, with minute short-oblong raphids, base with broad annuliform carpopodium; pappus straw-colored, of 45-65 crowded rather persistent capillary bristles, about as long as corolla, barbellate, mostly some somewhat broadened and flattened distally, a few outer shorter bristles rather indistinct. Pollen ca. 40-45 µm in diam., spinulose, sublophate, tricolporate, with continuous perforated tectum between colpi.
In addition to the diagnostic generic characteristics are features of special interest such as the marginal teeth of the leaves that are incurved and appressed against the abaxial surface in all but one species ( Cuatrecasanthus lanceolatus ; Fig. 1A-B View Figure 1 ) and the finely branching myceliiform hairs on the abaxial surface of the leaves in all the species ( Fig. 1C View Figure 1 ). In addition, there is variation on the leaf surfaces. The surfaces of the leaves have veins that can be exsculpate (above the surface), insculpate (below the surface), or even with the adaxial leaf surface ( Figs 2 View Figure 2 -4 View Figure 4 ). All but one of the species have veins on the adaxial surface that are even with the surface or slightly insculpate; one species has veins that are deeply insculpate ( Cuatrecasanthus giannasii ) and all six species have veins that are exculpate on the abaxial surface. The style branches are reported on one herbarium label as pale pink almost white; there are no additional data on the color of the styles.
The genus occurs in Ecuador and Peru. The six known species can be distinguished using the following key:
| 1 | Leaf margins with numerous obvious antrorse teeth not strongly incurved against abaxial surface (may vary in prominence); leaf tips narrowly acute, not abruptly short-acuminate | 5. Cuatrecasanthus lanceolatus |
| - | Leaf margins entire or with obscure inturned teeth; leaf tips usually abruptly short-acuminate | 2 |
| 2 | Inflorescence with loose clusters of heads, distinctly exceeding the upper leaves | 3 |
| - | Inflorescence with dense clusters of heads, not or scarcely exceeding the upper leaves, with interspersed foliiform bracts | 4 |
| 3 | Leaf blade broadly elliptical or ovate-elliptical; adaxial surface hispidulous with midvein prominently exculpate and otherwise plane | 4. Cuatrecasanthus kingii |
| - | Leaf blade lanceolate-elliptical; adaxial surface sparsely covered with appressed minute tricihomes with at least the midvein insculpate | 6. Cuatrecasanthus sandemanii |
| 4 | Adaxial surface of leaf with all veins distinctly insculpate; adaxial surface with few short trichomes, veins and trichomes all whitish; distal leaf margins with incurved teeth pressed against abaxial leaf surface; tips of pappus bristles distinctly broadened | 2. Cuatrecasanthus giannasii |
| - | Adaxial surface of leaf with major veins not obviously insculpate, secondary and tertiary veins insculpate; adaxial surface with many prominent stiff trichomes, midvein and trichomes dark brown or yellow; leaf margins with few inturned teeth; tips of pappus bristles not or scarcely broadened | 5 |
| 5 | Abaxial surface of midvein of leaf with dense antrorse pubescence mostly on sides; abaxial surface of lamina covered with mostly appressed, stiff, usually brownish trichomes | 1. Cuatrecasanthus flexipappus |
| - | Abaxial surface of midvein of leaf densely hirsute with spreading hairs; abaxial surface of lamina with erect yellowish trichomes | 3. Cuatrecasanthus jelskii |
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