Cuspidaria
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publication ID |
https://doi.org/ 10.5252/adansonia2023v45a12 |
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DOI |
https://doi.org/10.5281/zenodo.8015269 |
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persistent identifier |
https://treatment.plazi.org/id/039687DC-FFD2-9128-8F08-C2B9FA14A8FF |
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treatment provided by |
Felipe |
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scientific name |
Cuspidaria |
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VIII. Cuspidaria View in CoL View at ENA - Tynanthus clade
TAXONOMIC INFORMATION. — This clade contains two genera, Cuspidaria and Tynanthus , both with four phloem wedges in transversal section. While the circumscription of Tynanthus has remained constant in different classification systems, Cuspidaria currently includes species from three previously recognized genera (see Fischer et al. 2004; Table 1 View TABLE ), Cuspidaria, Arrabidaea , and Pyrostegia .
TOTAL NUMBER OF SPECIES IN THIS CLADE. — 35 species belonging to Cuspidaria (21) and Tynanthus (14) ( Lohmann & Taylor 2014; Medeiros & Lohmann 2015; Kaehler et al. 2019).
STUDIED SPECIES. — Four species, Cuspidaria convoluta (Vell.) A.H.Gentry , C. pulchra (Cham.) L.G.Lohmann , Tynanthus cognatus (Cham.) Miers , and T. elegans (Vell.) L.G.Lohmann.
Regular phloem
Thin to thick fiber bands, assemblages present ( Fig. 11D View FIG ). Mostly thin fiber bands in T. cognatus ( Fig. 11D View FIG ).
Variant phloem
General configuration. Fibrous ( Fig. 11 View FIG A-C, E, F), with axial elements in a tangential arrangement of one row of sieve tubes, surrounded by a sieve-tube-centric phloem parenchyma ( Fig. 11 View FIG A-C). A band of parenchyma sometimes present ( Fig. 11F View FIG ).
Sieve-tube elements. As seen in transverse section, each sieve element is associated with 2-3 (sometimes over 4) companion cells that occur at the same side of the sieve element ( Fig. 11B, E View FIG ). The sieve elements generally occur in multiples of 2-3 (up to 5) radially elongated cells ( Fig. 11B View FIG ). Solitary sieve elements are also present in Cuspidaria ( Fig. 11F View FIG ). As seen in transverse section, the sieve elements are of variable length, from 400 µm to approximately 1 mm and their end walls are inclined, bearing compound sieve plates with 12- 30 sieve areas ( Fig. 11G View FIG ).
Axial parenchyma. The phloem parenchyma is typically sieve-tube-centric, surrounding the groups of sieve elements ( Fig. 11B, C, E, F View FIG ). In Cuspidaria convoluta , lignified lines of phloem parenchyma cross the entire phloem wedge ( Fig. 11C View FIG yellow arrows); some non-lignified lines are also found occasionally in this species ( Fig. 11F View FIG ).
Fibers. Fibers are very abundant, forming background tissue ( Fig. 11 View FIG A-C, F).
Rays. The limiting rays are lignified to both xylem and phloem faces ( Fig. 11A View FIG ), with a radial row non-lignified between them. The wedge rays have randomly alternating portions lignified and non-lignified. The lignified portions never bear crystals and are differentiated very close to the cambium.
Crystals. Acicular and navicular crystals are present solely on the non-lignified portions of the phloem and ray parenchyma.
Periderm
A single periderm is formed. The phellem is stratified, composed of thin and thick-walled cells in alternation. The phelloderm is thick, with over three cell layers, non-stratified ( Table 2 View TABLE ). In Tynanthus the lenticels are non-stratified, with unlignified filling tissue ( Table 2 View TABLE ). In Cuspidaria the lenticels are stratified, with a closing layer of lignified cells ( Table 2 View TABLE ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.