Cathetus fasciculata de Loureiro, 1790

Kemprai, Kapil Kumar, Basumatary, Kshiprativ & Borah, Souravjyoti, 2025, Synonymization of the name Cathetus roeperianus (Phyllanthaceae) with an emended description and lectotypification of Cathetus fasciculata from the collections of India, Phytotaxa 706 (2), pp. 139-147 : 141-145

Cathetus fasciculata de Loureiro in Fl. Cochinch (1790: 608).

Lectotype (designated here):─ VIETNAM, Cochinchina : s.d. J. de Loureiro s.n . Lectotype here designated: BM, barcode BM000951422 (digital image!) . Isolectotype: BM000951421 (digital image!).

≡ Phyllanthus cochinchinensis Spreng (1826: 21)

= Cathetus roeperianus (Wall. ex Müll.Arg.) Chakrab. & N.P. Balakr. (2022: 43) in JETB 46(1–2): 42–45. 2022, syn. nov.

Description: — Shrub, upto 2.5 m tall; stem yellowish-green, yellowish-brown in young ones, dark maroon/reddish brown in mature ones; branchlets 10 cm to about 27 cm, branched, striated angled towards the tip, glabrous. Leaves narrowly oblong to linear-oblong, also oblong-elliptic and/or ovate-elliptic, somewhat rounded cordate, cuneate or acute at base, apiculate, acute, sub-acute or mucronate, sometimes obtuse or rounded at apex, 06–29×02–09 mm; midrib slightly raised on both the surfaces; lateral nerves in leaf 4–9 pairs; petioles very minute, a little less than 1 mm upto 2 mm long glabrous; stipules subulate, deltoid-acuminate, 1–1.5× 0.5–1 mm, peltate; leaf margin narrowly revolute when dried. Inflorescence axillary, cymules bisexual, 1–2(–4) flowered; bracts dense, tufts, brown-hairy, 0.5–1× 0.4–0.8 mm, fimbriate margins. Male flowers: pedicels ca. 3 mm long; sepals 6, obovate, spathulate, ca. 1× 0.4– 0.6 mm, obtuse; disc glands 6, very small, orbiculate; stamens 3; filaments 0.4–0.6 mm long, connate below into a column; anthers orbicular. Female flowers: pedicels 5–10 mm long; sepals 6, oblong elliptic, obovate, obovate-oblong, 1–1.5× 0.5–1.3 mm, undulate; disc annular; ovary ovate/globose, ca. 0.5–1.0 mm in diameter, 3-lobed; styles 3, 0.5–1 mm long, connate below into column, bifid at the apex. Fruit sub-globose, 2–3 mm in diameter, capsules oblate, 3- lobed, smooth; seeds tawny in colour, wedged-shape, trigonous, with ca. 1–1.2 mm long.

Specimens examined: — India, Assam, Dima Hasao District, Bendao Baiglai waterfalls (25 ⁰14′26″ N; 92 ⁰58′50″ E), 29 September 2023, K. K. Kemprai & S. Borah GUBH-020631 ; Rani Reserve Forest (26 ⁰03′43″N; 91 ⁰41′01″E), 09 January 2024, K. Basumatary & K. K. Kemprai in GUBH-020630 ( Figure 3 ) .

Distribution: — Native to Assam (erstwhile), Bangladesh and Myanmar ( POWO, 2024); In India, along the edges of forests, wastelands, rocky crevices or near streams, between 1000–1800 m altitudes, Meghalaya and Manipur ( Balakrishnan et al. 2012); presently in Dima Hasao (Bendao Baiglai waterfalls) Assam and Rani Reserve Forest of Assam.

Flowering and Fruiting: — Mid of August to February.

Notes: — Spreng (1826) while describing the name P. cochinchinensis for the first time mentions the leaves to be bundled up or compact, minute in structure, ovate and glabrous, with much smaller capsules. But on comparison with the specimens collected from Assam, India, it was found that, the specimens represent morphological affinities to the specimens housed at the herbarium of Botanical Survey of India, Eastern Regional Centre(ASSAM!), which are collections from Meghalaya and erstwhile Assam state of India and to the available literature description from the specimens of China. Moreover, it was found that the size of the capsules was in range of about 2–3 mm long in both the distinctly described species from India and China with oblate nature of the capsules. Through Scanning Electron Microscopy (SEM) observations, it is found that the trigonous seeds had a wart-like, longitudinally verrucate ornamentation in the seed coat. Bouman et al. (2022) mentions the verrucate nature of the seeds as a diagnostic character for the genus itself.

According to Bouman et al. (2022), the reinstated genus Cathetus is the oldest name at the generic level, even though it was earlier only a section within Phyllanthus , thus the name Cathetus has priority in naming. On observing and examining the descriptions of both P. cochinchinensis and the Indian species of C. roeperianus , it was found that the diagnostic characters presented for each are well within the limits and range of similarity and is rather not contrasting for its consideration to uphold at the species level. The specimen studied was collected from Dima Hasao district, Assam, India, 2023 and Rani Reserve Forest, Assam in 2024. It was upto about 2m tall, in full bloom and fruiting condition with shiny glabrous leaves and reddish-brown stems and branchlets, growing along the stretch of the BendaoBaiglai waterfalls near Sampharidisa village. C. fasciculata is reported in 2 (two) states from India i.e. Meghalaya and Manipur ( Balakrishnan et al. 2012). Hence, the present collection and description of the specimen from Dima Hasao district of Assam, India constitutes a new record to the Assam Flora.

On searching for the type specimens of C. fasciculata , two sheets i.e BM000951421 & BM000951422 were located at the herbarium of the Natural History Museum (BM) which were collections from Cochinchina ( Vietnam), the latter having labels with annotation that reads “ Cochinchina-Loureiro ” by Loureiro and both as such are original materials ( GBIF 2025). The sheet BM000951422 is selected as the lectotype as per Art. 9.3 of ICN ( Turland et al. 2018), since the locality of the collection and collectors name is mentioned on the sheet label and hence deemed appropriate to be designated as type ( Figure 4 ) and the other (BM000951421) is designated as the isolectotype. Bouman et al. (2022) has had correctly cited P. cochinchinensis as a homotypic synonym of C. fasciculata but however erred in the use of symbol (‘=’ was used instead of ‘≡’) for citation of the synonym ( P. cochinchinensis ) while designating C. fasciculata as the type of the resurrected genus Cathetus .

Figures

FIGURE 3. Cathetus fasciculata de Loureiro—Distribution map (A–D). showing the collection sites for the purpose of study.

FIGURE 4. Lectotype of Cathetus fasciculata (designated here). Source: Natural History Museum (2025). Natural History Museum (London) Collection Specimens. Occurrence dataset https://doi.org/10.5519/qd.x8gq8f5t accessed via GBIF.org on 2025- 05-02. https://www.gbif.org/occurrence/1057063963.