﻿A taxonomic revision of Thai Fernandoa Welw. ex Seem. (Bignoniaceae)

﻿Abstract A taxonomic revision of Fernandoa Welw. ex Seem. (Bignoniaceae) in Thailand is presented. Two species, F.adenophylla (Wall. ex G. Don) Steenis and F.collignonii (Dop) Steenis, are enumerated with updated morphological descriptions, illustrations and a taxonomic identification key, together with notes on distributions, distribution maps, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. The collection of Wallich Cat. 6502A from Myanmar, Ava at G [G00133642] is designated here as the lectotype of F.adenophylla in a second step lectotypification. F.collignonii has a conservation status of Endangered [EN]. The leaf, stem, and wood anatomy and pollen morphology of F.adenophylla are also reported in this study.

Morphologically, Fernandoa is similar to Radermachera Zoll.& Moritzi and Stereospermum Cham. in having decussate leaves, leaf rachises not keeled above, leaflets less than seven pairs, and septum of the ovary flat and without pseudoseptum.Fernandoa differs from Radermachera and Stereospermum based on lower surface of the leaflets with hairy domatia, fruits with longitudinal ribs, septum flat (vs lower surface of the leaflets without hairy domatia, fruits without longitudinal ribs, septum terete in Radermachera and Stereospermum) (Santisuk 1987;Fischer et al. 2004).
In Thailand, a taxonomic revision of the genus Fernandoa was published by Santisuk (1987) and two species were recognized, F. adenophylla and F. collignonii.In this paper, we had extensively examined Thai specimens of Fernandoa in various local and international herbaria including digital herbarium repositories.As a result, we hereby provide a comprehensive update to species descriptions, habitats and vernacular names, in addition to phenological observations, uses, IUCN conservation status, illustrations and distribution maps in Thailand for each species.Besides that, leaf, stem and wood anatomical characters and pollen morphology of F. adenophylla are presented, excluding F. collignonii because we did not collect specimens of this species.

A key to the species of Fernandoa in Thailand
Distribution.India (Assam, Andaman and Nicobar Islands), Pakistan, Bangladesh, Myanmar, Vietnam, Laos, Cambodia, Thailand, Peninsular Malaysia.Phenology.Flowering and fruiting nearly all year round.Conservation status.Fernandoa adenophylla is widely distributed from India to Indochina and Peninsular Malaysia, and has a large extent of occurrence (EOO of 3,353,755.49km 2 ) and area of occupancy (AOO of 352 km 2 ).Also, considering it grows in secondary forests, disturbed open areas, and along roadsides, it is considered here as Least Concern (LC).
Uses.Flowers and young fruits are consumed as boiled or grilled vegetables and required cooking.Cultivated as shade and ornamental trees (the author's observations).The wood is locally used in construction and used for making farming utensils.Bark, leaves, and seeds are used as medicinal purposes (Widodo 1998;Biodiversity-Based Economy Development Office (Public Organization) [BEDO] 2021).
Notes.Bignonia adenophylla was named by Wallich based on Wallich Cat.6502 collected from Myanmar: 6502A from Irrawaddy River, Yenangheum (Yenangyaung), Prome, Sagaen (Sagaing), and Ava and 6502B from Taong Dong but unpublished, and then this name was described by Don (1838: 221).van Steenis (1976: 135)  van Steenis (1976) cited Wallich Cat.6502 from Ava and Prome at G as the holotype with isotypes in K and P.However, Wallich's collection numbers are known to be curated by species generally from multiple collections (Noltie and Watson 2021); therefore, his erroneous designation of holotype effectively selected a) a collection for the lectotype if the collection consists of multiple sheets or b) the lectotype if it is a unicate gathering.van Steenis (1976) did not mention the number of specimens, and following Art.9.6 of the ICN (Turland et al. 2018), they constitute syntypes.Therefore, the name Fernandoa adenophylla has been lectotypified in a first step by van Steenis (1976) using specimen Wallich Cat.6502A at G [without barcode] with isolectotypes at K [without barcode] and P [without barcode].We located three sheets of the specimen Wallich 6502A from Ava at G [G00133642, G00134691, and G00134695] and two sheets of the specimen Wallich 6502A from Prome at G [G00133632 and G00134708]; The G [G00133642] specimen is better preserved and more complete than the others, and hence is selected here in a second step lectotypification.We also traced isolectotypes at K-W [K001124064] and P [P00609736].Santisuk (1987) reported that the leaves, calyx, and ovary have a stellate tomentum, but in this study the calyx, corolla, ovary, and fruits only exhibited dendroid trichomes, whereas the leaves bear both stellate and dendroid trichomes.
Phenology.Flowering April to July; fruiting July to December.Conservation status.Endangered (EN) (Santisuk et al. 2006;Chamchumroon et al. 2017).This species is known only from Indochina (Vietnam, Laos, and Thailand), and has a small extent of occurrence (EOO of 14,250.11km 2 ) and area of occupancy (AOO of 20 km 2 ).In Thailand it is known only from Northern Thailand, Nan Province, and has a small extent of occurrence (EOO of 1,378.75km 2 ) and area of occupancy (AOO of 16 km 2 ).It is appropriate to consider its status as Endangered [EN B2ab(ii,iv)].
Etymology.The specific epithet of Fernandoa collignonii honours L. Collignon, the collector of the type specimen.Uses.No data recorded in Thailand.In Vietnam, Tonkin, Hoa Binh, the specimen Poilane 13012 (P [P02862885]) noted that its timber is good for all purposes, not being attacked by termites.
Notes.In addition to the key to the species, Fernandoa collignonii differs from F. adenophylla in its petioles 3.5-9 cm long (vs very short or up to 1.5 cm long because the lowest pair of leaflets near the base of petiole much reduced, resembling foliaceous pseudostipules), rachises terete (vs 4-angular), petioles and rachises sparsely hairy or glabrous (vs densely stellate and dendroid tomentose), the longest leaflets up to 17 cm (vs the longest terminal leaflets up to 46.5 cm and lateral leaflets up to 33 cm), leaflets chartaceous, with a few scattered glands below (vs subcoriaceous, with scattered glands on both surfaces).Santisuk (1987) reported that the height of this species ranges from 5-12 m tall, but the specimens Srisanga et al.The flowers were mentioned by the specimens from Vietnam, Evrard 515 (L [L2815229]) to be reddish orange (rouge ochre), and Poilane 6055 (L [L2815228]) described them as white, but were recorded here as creamy white to pale yellow in this study.

Leaves, stems (branches) and wood anatomy of Fernandoa adenophylla
This species has branched eglandular trichomes, and are uniseriate, unicellular.The unicellular trichomes have only one cell but are quite variable in length.Branched eglandular trichomes can be divided into two types: stellate (starshaped, with many branches radiating outwards) and dendroid (have a tree-like branching form).Both trichomes are also found on the petioles, rachises, and inflorescences (peduncles, axes, and pedicels), except on the calyx, corolla, ovary, and fruits where is only found a dendroid trichome.(Fig. 6A-C) Peltate glandular trichomes that are sunken into epidermal cells on both surfaces.The cuticular ornamentation is deposited on the outer wall of the epidermal cells.The epidermal cells are arranged in a single layer on both surfaces, and are larger on the upper surface than on the lower one.The epidermal cells on the upper surface are polygonal in shape with straight anticlinal walls, and on the lower surface are irregular in shape with undulate (wavy) anticlinal walls.The stomata are confined to the lower surface and are anomocytic.The mesophyll composed of palisade parenchyma (also called palisade mesophyll) underlying the upper epidermis and spongy parenchyma (also called spongy mesophyll) underlying the lower epidermis (bifacial leaf).The palisade parenchyma exhibits two layers: an upper tall one and a basal layer, about half in height, tightly packed cells and the spongy parenchyma comprised of loosely packed, irregularly shaped cells.In the midrib, the sclerenchymatous sheath of stele is made both by phloem fibers and lignified rays.Stele interpreted as two crescents, almost flat above and arched below, perhaps with two small bundles in the upper corners.The presence of sclerenchyma cells in the midrib is to provide support and protection for the leaf structure.(Fig. 6D-G).
The outline of the rachises in transverse section is 5-angular, it is channeled on the upper side.Stellate and dendroid trichomes are present as in the laminas.The epidermis in transverse section is circular or semicircular, and cells are usually smaller than cells in the ground tissue.The cortex of the young rachises is broader than the mature rachises.Parenchyma predominates in ground tissue, and fiber cells are present.The vascular bundles are completely ensheathed by sclerenchyma cells.The xylem is incompletely surrounded by phloem, interspaced with sclerenchyma cells.(Fig. 6H, I).
Secondary growth of stems (branches): The bark is made up of the periderm (also called outer bark), the cortex, and the phloem (also called inner bark).The periderm is 7-10 layered.The cortical parenchyma is 7-8 layered.The cells of the vascular cambium divide and supply secondary phloem and xylem.Fibers occur both in the primary and the secondary phloem.The pith is only parenchymatous.(Fig. 7A, B).
Fernandoa adenophylla has diffuse-porous wood.Vessels (pores) are solitary and form in groups of 2-4 cells or more, 20-100 µm in diam.Vessel density ranges from 4-20 vessels per mm 2 .Axial parenchyma patterns are confluent.Rays are heterocellular, biseriate, sometimes uniseriate, with the procumbent cells 3-12 cells long, and with one row of the upright cells at both ends, and are sometimes homocellular with only the upright cells 2-3 cells long.The septate fibers are present.(Fig. 7C-E) The result of this study is consistent with Metcalfe and Chalk (1957) which reported wood anatomy of Fernandoa: rays are homocellular, sometimes heterocellular, with 4-11 cells long, and fibers are septate.
A comparison of wood anatomical characteristics of Fernandoa adenophylla with the previous studies of other two genera, Dolichandrone (Boonthasak and Ngernsaengsaruay 2021) and Santisukia (Meeprom et al. 2022) in the tribe Tecomeae of the family Bignoniaceae in Thailand is shown in Table 1.

Pollen morphology of Fernandoa adenophylla
The pollen grains of Fernandoa adenophylla are monads, isopolar, tricolpate, oblate, suboblate to oblate-spheroidal in shape.The size of the pollen grains is medium to large, the polar axis ranges between 29-55 µm, and the equatorial axis ranges between 27-54 µm.The exine sculpturing is reticulate.(Fig. 8) Santanachote (1981) reported that the pollen grains of this species are suboblate in shape, the polar axis ranges between 41-51 µm, and the equatorial axis ranges between 35-41 µm which shows slight differences in shape and size from this study.

Ethical statement
No ethical statement was reported.

Figure 1 .
Figure 1.Fernandoa adenophylla A habitat and habit B bark C branch and leaves D branches, leaves and inflorescences E inflorescences and flowers F branches, leaves, inflorescences and fruits G winged seeds.Photos: Yanatshara Attasook (A, B) Chatchai Ngernsaengsaruay (C-G).

Figure 3 .
Figure 3. Distribution of Fernandoa in Thailand: F. adenophylla occurs in all floristic regions of Thailand and F. collignonii known only from Nan Province, Northern Thailand.[Thailand floristic regions follow Flora of Thailand Volume 16 Part 1 (The Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation 2022)].

Figure 7 .
Figure 7. Stem (branch) and wood anatomy of Fernandoa adenophylla A, B transverse section secondary growth of stem C-E wood anatomy C transverse section D radial longitudinal section E tangential longitudinal section (shown in an oblique orientation) [Ap = axial parenchyma, Ct = cortex, P = pith, Pd = periderm, Pf = phloem fiber, Ph = phloem, Rp = ray parenchyma, V = vessel, Xf = xylem fiber, Xy = xylem], the stain combination safranine and fast green.

Figure 8 .
Figure 8. SEM micrographs of pollen grains of Fernandoa adenophylla A polar view B equatorial view.
; Office of the Forest Herbarium, Forest and Plant Conservation Research Office, Department of National Parks, Wildlife and Plant Conservation 2014).The assessment of conservation status was performed following the IUCN Red List Categories and Criteria (IUCN Standards and Petitions Committee 2022) for a preliminary assessment PhytoKeys 235: 249-270 (2023), DOI: 10.3897/phytokeys.235.112839ChatchaiNgernsaengsaruayet al.: Thai Fernandoa Welw.ex Seem.(Bignoniaceae)
mentioned Wallich Cat.6502 of Ava and Prome as type, when he transferred B. adenophylla under Fernandoa adenophylla.Wallich Cat.6502 represents two gatherings (two different materials collected from two different cites, which are distinguished by Wallich Cat.6502A and Wallich Cat.6502B, respectively).Wallich Cat.6502A is from Ava and Prome and Wallich Cat.6502B is from Taong Dong.Thus, Wallich Cat.6502A could be regarded as the true type specimen, and Wallich Cat.6502B from Taong Dong is not type.

Table 1 .
A comparison of wood anatomical characteristics of Fernandoa adenophylla with other two genera, Dolichandrone and Santisukia in the tribe Tecomeae of the family Bignoniaceae in Thailand.