Adenocalymma
Creators: name: Pace, Marcelo R.
name: Marcati, Carmen R.
name: Lohmann, Lúcia G.
name: Angyalossy, Veronica
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Lamiales
Bignoniaceae
Adenocalymma

description: XV. Adenocalymma clade
TAXONOMIC INFORMATION. — This clade contains a single genus, Adenocalymma, with four to multiples of four phloem wedges in transversal section. In the most recent circumscription of the genus (Fonseca & Lohmann 2019), Adenocalymma houses four genera recognized in previous classification systems (see Fischer et al. 2004; Table 1), Adenocalymma, Gardnerodoxa Sandwith, Memora, and Neojobertia Baill.
TOTAL NUMBER OF SPECIES IN THIS CLADE. — 76 species (Fonseca & Lohmann 2019).
STUDIED SPECIES. — 13 species, Adenocalymma adenophorum (Sandwith) L.G.Lohmann, A. alboaurantiacum (Faria & Proença) L.H.Fonseca & L.G. Lohmann, A. bracteatum (Cham.) DC., A. acutissimum (Cham.) Miers., A. divaricatum Miers., A. flaviflorum (Miq.) L.G.Lohmann, A. longilineum (A. Samp.) L.G.Lohmann, A. mirabilis (Sandiwth) L.H.Fonseca & L.G.Lohmann, A. nodosum (Silva Manso) L.G.Lohmann, A. peregrinum (Miers.) L.G.Lohmann, A. salmoneum J.C.Gomes, A. tanaeciicarpum (A.H.Gentry) L.G.Lohmann, and A. validum (K.Schum.) L.G.Lohmann.
Regular phloem
Thin to thick fiber bands (Fig. 17A, 18A), assemblages absent or present (present in Adenocalymma bracteatum, A. divaricatum, A. salmoneum, and A. validum).
Variant phloem
The variant phloem of Adenocalymma is by far the most diverse in Bignonieae. In fact, besides from the wedge number, either four or in multiples of four, Adenocalymma species can range from non-fibrous, semi-fibrous (Fig. 17B) to fibrous, with axial elements ranging from radially to tangentially arranged, sometimes with radial groups of 2-3 sieve tiubes (Fig. 17B), sometimes in clusters. Given the high diversity of the secondary phloem of Adenocalymma, we here divide them in three distinct groups based on their phloem structures.
Group 1: Non-fibrous Adenocalymma
Six of the analyzed species were included in this group: Adenocalymma adenophorum, A. bracteatum, A. flaviflorum, A. longilineum, A. nodosum, and A. peregrinum.
General configuration. Non-fibrous (Fig. 18B), with approximately 7-13 rows of sieve tubes and phloem parenchyma between fiber bands. The axial elements present a radial to diffuse arrangement.
Sieve-tube elements. As seen in transverse section, each sieve element is associated with 2 companion cells, one at each corner of the sieve element (Fig. 18C). The sieve elements are generally in multiples of 2-3, sometimes solitary (Fig. 18C). Sieve tubes of narrower radial diameter are present in A. nodosum associated with a tangential parenchyma band. As seen in longitudinal section, the sieve elements are short (<1 mm) and their end walls are inclined, bearing sieve plates with 7-14 sieve areas.
Axial parenchyma. The phloem parenchyma intermingles all other cells (Fig. 18B, C), and form radial rows of 3-5 cells at certain portions. A tangential band is also present in Adenocalymma nodosum.
Fibers. Fiber bands of 2-5 rows of cells are present (Fig. 18B).
Rays. The limiting rays are lignified only to the xylem face. The wedge rays are non-lignified, except when crossing the fiber bands (Fig. 18B) and except in A. longilineum, which present portions of the rays lignified even when not touching the fiber bands.
Crystals. Crystals are absent in Adenocalymma peregrinum. Prismatic crystals are present in A. adenophorum, A. flaviflorum, A. longilineum and A. nodosum, being restricted to the ray cells crossing the fiber bands in A. adenophorum and A. flaviflorum and being scattered and rare in phloem and ray parenchyma cells of A. nodosum.
Group 2: Semi-fibrous Adenocalymma
Three of the analyzed species were included in this group: Adenocalymma comosum, A. mirabilis, and A. salmoneum.
General configuration. Semi-fibrous (Fig. 17B, C, 18E), exhibiting wavy fiber bands (Fig. 17B, 18E). The axial elements show a tangential arrangement (Fig. 18E).
Sieve-tube elements. As seen in transverse section, each sieve element is associated with one companion cell. The sieve elements are generally in multiples of 2-3 (Fig. 17B), rarely solitary, with sieve elements in both radial and tangential rows, sometimes in clusters (Fig. 18E). As seen in longitudinal section, the sieve elements are short (<1 mm) and their end walls are inclined, bearing sieve plates with 7-12 sieve areas.Axial parenchyma.The phloem parenchyma forms the
background tissue (Fig. 17B), it is complete in A. salmoneum,
and without this arrangement in A. comosum. In addition, radial rows of 4-7 cells of phloem parenchyma are present in some places.
Fibers. Fiber bands wavy, in some portions thicker than in others (Fig. 17B, C, 18E).
Rays. The limiting rays are lignified only to the xylem face. The wedge rays can be non-lignified or lignified, especially when crossing the fiber bands (Fig. 17B, C, 18E).Crystals.Crystals are very abundant, being styloid and acicular
in A. comosum, prismatic to styloid in A. mirabile (Fig. 17C), prismatic in A. salmoneum, and prismatic and acicular in A. validum.
Group 3: Fibrous Adenocalymma
Three of the analyzed species were included in this group: Adenocalymma alboaurantiacum, A. divaricatum, and A. validum.
General configuration. Fibrous (Fig. 18D, F, G), presenting a matrix of fibers in which all other cells are embedded (Fig. 18D, F, G). The axial elements show a tangential arrangement (Fig. 18D, F).
Sieve-tube elements. As seen in transverse section, each sieve element is associated with one companion cell, sometimes two in A. validum, one in each corner of the sieve element. The sieve elements occur in multiples of 2-3, sometimes solitary (Fig. 18F). As seen in longitudinal section, the sieve elements are short (<1 mm) and their end walls are inclined, bearing sieve plates with 7-10 sieve areas. Reticulated sieve plates are present in A. divaricatum.
Axial parenchyma. The phloem parenchyma is sieve-tube-centric incomplete in A. validum, complete in A. alboaurantiacum (Fig. 18F), and A. divaricatum. Radial rows of phloem parenchyma can be also detected alternating with sieve elements and near the ray cells.
Fibers. A matrix of fibers is present (Fig. 18D, F, G). Fibers are more abundant in A. divaricatum (Fig. 18D) than in the other species studied.
Rays. The limiting rays are lignified only to the xylem face, but with some portions lignified also to the phloem face (Fig. 18D). The wedge rays have randomly alternating portions lignified and non-lignified (Fig. 18D).Crystals.All species in this group present crystals in the ray
cells (Fig. 18F, G). They are prismatic in A. divaricatum, prismatic in A. salmoneum, and prismatic and acicular in A. validum (Fig. 18F, G).
Periderm
A single periderm is formed (Fig. 17A) in all species, except for Adenocalymma flaviflorum, which also forms a rhytidome. The phellem can be non-stratified and evenly thin-walled in A. bracteatum and A. flaviflorum or non-stratified and evenly thick-walled in A. comosum, A. divaricatum, A. peregrinum, and A. salmoneum (Table 2). The phellem is stratified in A. mirabile and A. validum, with alternating thin and thick-walled cells (Fig.17A). In Adenocalymma validum, there is also an alternation of cells with dark content and cells without any conspicuous content. The phelloderm is non-stratified (Fig. 17A), thin in A. comosum and A. peregrinum, or thick-walled, in A. bracteatum, A. divaricatum, A. flaviflorum, A. mirabile, A. salmoneum, and A. validum (Table 2). Lenticels are stratified in Adenocalymma comosum, A. peregrinum, A. salmoneum, and A. validum and non-stratified, with unlignified filling tissue in A. flaviflorum (Table 2). Lenticels were not observed in A. mirabile.
description: Published as part of Pace, Marcelo R., Marcati, Carmen R., Lohmann, Lúcia G. & Angyalossy, Veronica, 2023, Bark anatomy of lianescent Bignoniaceae: a generic synopsis, pp. 167-210 in Adansonia (3) (3) 45 (12) on pages 195-196, DOI: 10.5252/adansonia2023v45a12, http://zenodo.org/record/8006364