MADAGASCAR – Diana region [Antsiranana prov.] • Montagne des Français, descent of the canyon starting from the ruins of the military camp; 12°19’46”S, 49°20’23”E; 260 m; 6 Apr. 2007; Bardot-Vaucoulon M., Véné G. & Razafindrabelahasy G. 1645; holotype: P [P00643172]; isotypes: K, MO [MO-2966289, accession n° 6120147], TAN (not seen).

Acalypha bardotiana is morphologically close to A. lanceolata Willd. var. glandulosa (Müll.Arg.) Radcl.-Sm. but differs mainly by having a suffruticose habit and unisexual inflorescences (vs herbaceous habit and androgynous inflorescences), conspicuous stipules up to 8 mm long (vs inconspicuous stipules up to 2 mm long), petioles up to 8 mm long and leaf blades up to 9 cm long (vs petioles up to 4.6 mm long and leaf blades up to 6.5 cm long), and papillose-hispid capsules (vs smooth capsules).

Suffruticose herbs, 0.5−0.6 m tall, monoecious. Branches pubescent with short, antrorsely curved, simple trichomes and long, erect trichomes to 1 mm long, glabrescent when mature. Axillary buds inconspicuous. Stipules conspicuous, up to 8 mm long and 3.5 mm wide at base, ovate-lanceolate to triangular-lanceolate, acuminate, sparsely hairy with long, simple trichomes to 1 mm long and minute glandular trichomes at margin. Petioles thin, 6–8 cm long, indumentum similar to that on young branches. Leaf blades 6–9 × 4–6 cm, broadly ovate to elliptic-lanceolate, membranous; base obtuse to subcordate; apex acute to acuminate; margins serrate, teeth rounded, sometimes mucronate; upper surface with sparse, erect, simple trichomes up to 1 mm long; lower surface subglabrous, with appressed simple trichomes on veins; venation actinodromous, basal veins 3(–5), secondary veins 4–5 per side. Stipels absent. Inflorescences spiciform, unisexual, male axillary, female terminal on lateral branches. Male inflorescences up to 3 cm long, flowers glomerate; bracts minute to 0.5 mm long, linear-lanceolate, sparsely hairy. Female inflorescences moderately densely flowered, up to 8 cm long; peduncle up to 1 cm long, indumentum similar to that on young branches; bracts to 30, sessile, enlarging in fruit to 2.5 × 5 mm, sparsely hairy with erect, hyaline, simple trichomes up to 1 mm long and glandular trichomes up to 1 mm long; margin deeply dentate, teeth 10–12, triangular, acute, up to 1.5 mm long, central tooth not prominent; bracteoles absent. Male flowers with pedicel up to 0.5 mm long, glabrous; buds up to 0.5 mm diameter, glabrous. Female flowers 1 per bract, sessile; sepals 3, up to 0.5 mm long, distinct, ovate-lanceolate, ciliate, with minute simple trichomes up to 0.2 mm long; ovary ca 1 mm diameter, 3-lobed, papillose-hispid, each papilla ending in a long, hyaline trichome up to 1 mm long; styles 3, up to 5 mm long, slightly connate, each divided into 5–6 slender segments, with some hyaline erect trichomes up to 1 mm long. Allomorphic flowers not seen. Capsules up to 2.5 mm diameter, papillose-hispid, each papillae ending in a simple, erect trichome up to 1 mm long, surface sparsely hairy with minute, simple trichomes up to 0.2 mm long. Seeds ca 1.7 × 1 mm, pyriform, minutely foveolate.

The epithet honours Mrs Martine Bardot-Vaucoulon, a French botanist who has conducted extensive botanical research in Madagascar. She is also one of the collectors of the type specimens of this species and kindly provided us with some field images included in this paper.

Acalypha bardotiana is known only from the north side of Montagne des Français, at 260 m elevation. Montagne des Français is a limestone massif covered with dry deciduous forest, in the Diana region in the extreme north of Madagascar. Acalypha bardotiana grows on reduced clay soil on outcropping blocks of Eocene limestone, in an area of sparse vegetation on sunny rocks in the canyon (Fig. 4).

Acalypha bardotiana is only known from a single collection and location in the protected area of Montagne des Français. In this location, there were around ten individuals of this species (Martine Bardot-Vaucoulon pers. comm.). The extent of occurrence (EOO) could not be calculated. Its area of occupancy (AOO) is estimated to be 4 km². Montagne des Français has been relatively well collected (Porter P. Lowry II pers. comm.), so the absence of previous collections suggests this species is not common. Acalypha bardotiana is found in only one location, and its habitat is continuing to decline due to woodcutting, primarily for charcoal, and to the slash-and-burn agriculture (Goodman et al. 2018; Wilding et al. 2021). Acalypha bardotiana is assessed provisionally as Critically Endangered: CR B2ab(ii,iii,iv).

MADAGASCAR – Sava region [Antsiranana prov.] • Vohimarina district, Vohemar sub-prefecture, rural municipality of Daraina, Binara forest; 13°15.42’S, 49°36.8’E; 440 m; 22 Dec. 2003; Nusbaumer L. LN875; holotype: G [G00006971]; isotype: P [P04786262].

Acalypha inaequibracteata is morphologically similar to A. ankaranensis I.Montero & Cardiel, but differs mainly by having minute stipules up to 2 mm long, with simple trichomes (vs. stipules up to 5 mm long, with simple and glandular trichomes), petioles 0.5−1(–1.5) cm long (vs petioles 3−5 cm long), ovate to elliptic-lanceolate leaf blades that are rounded to obtuse at the base and lack domatia (vs broadly ovate-lanceolate leaf blades that are subcordate to cordate at the base and have pocket-shaped domatia), and dimorphic female bracts (vs monomorphic female bracts).

Shrubs, probably deciduous, 0.2−0.3 m tall, monoecious. Branches pubescent with short, antrorsely curved, simple, trichomes, glabrescent when mature. Axillary buds inconspicuous. Stipules inconspicuous, up to 1.5−2 mm long and 0.5 mm wide at base, triangular-lanceolate to linear-lanceolate, sparsely hairy with minute simple trichomes up to 0.2 mm long. Petioles thin, 0.5−1(−1.5) cm long, indumentum similar to that on young branches. Leaf blades (3−)4−5(–6) × 1.5−2(−2.7) cm, ovate to elliptic-lanceolate, membranous; base rounded to obtuse; apex acute to acuminate, acumen mucronate; margins crenate to serrate, teeth minute with small, sessile, glandular trichomes at apex; upper surface laxly pubescent with sparse, erect, simple trichomes up to 1 mm long and antrorsely curved trichomes on veins; lower surfaces with indumentum similar to that on the upper surface but less dense; venation actinodromous, basal veins 3(–5), secondary veins 4–5 per side. Stipels absent. Inflorescences spiciform, androgynous, and solitary female bracts, mainly axillary, some androgynous inflorescences terminal in lateral branches. Androgynous inflorescences up to 5.5 cm long; peduncle up to 0.8 cm long, indumentum similar to that on young branches; female segment up to 3 cm long, bracts 2−5, sessile, enlarging in fruit, dimorphic on the same plant (broadly ovate-lanceolate to subtriangular, up to 10 × 10 mm, on some inflorescences and oblate, up to 11 × 6.5 mm, on other inflorescences), both sparsely hairy with simple trichomes on both surfaces, oblate bracts also with minute glandular trichomes on lower surface; margin crenate to subentire, with minute, sessile, glandular trichomes at tooth apices, central tooth not prominent, bracteoles up to 0.6 mm long, triangular, sparsely hairy; usually there are inflorescences with all the bracts of the female segment oblate and other inflorescences with all the bracts of the female segment ovate-lanceolate to subtriangular; male segment persistent, up to 2.5 cm long, flowers glomerulate, bracts up to 0.5 mm long, triangular, sparsely hairy. Solitary female bracts mostly broadly ovate-lanceolate to subtriangular, similar to those found on androgynous inflorescences. Male flowers with pedicel up to 0.5 mm long, glabrous; buds up to 0.5 mm diameter, sparsely hairy, papillose. Female flowers 1 per bract, sessile; sepals 3, up to 0.7 mm long, distinct, triangular, ciliate with minute simple trichomes up to 0.2 mm long; ovary ca 1 mm diameter, 3-lobed, densely papillose-hispid, each papilla ending in a long, hyaline trichome up to 1 mm long; styles 3, up to 6 mm long, distinct, each divided into 6–7 very slender segments, sparsely hairy. Allomorphic flowers not seen. Capsules (immature) up to 2 mm diameter, papillose-hispid, each papilla ending in a simple trichome up to 1 mm long, surface pubescent with simple, minute trichomes. Seeds not seen.

The specific epithet refers to the presence of female bracts showing different shapes.

Acalypha inaequibracteata is known only from the Binara forest, in Daraina commune, Sava region, at 440 m elevation. The Binara forest is located in north-eastern Madagascar. Acalypha inaequibracteata grows on secondary grassland at the edge of the dense humid semi-deciduous forest, on rough boulders. (Fig. 4).

Acalypha inaequibracteata is only known from a single collection and location. The extent of occurrence (EOO) could not be calculated. Its area of occupancy (AOO) is estimated to be 4 km². The Binara forest belongs to the network protected area of Loky-Manambato (Category V; Dudley 2008) and still is relatively well preserved but recently, human activities are affecting the habitat where A. inaequibracteata occurs. The main current threats to the site are subsistence farming and fires to clear land for grazing, logging, and mining (Rakotondravony 2006; Goodman et al. 2018; BirdLife International 2003). Due to these threats, A. inaequibracteata could be affected in the near future and we do not know if this species grows in other nearby areas. The presumably continued degradation of the habitat lead us to assess A. inaequibracteata as Critically Endangered: CR B2ab(ii,iii,iv).

We found a specimen at K labelled L. Nusbaumer LN875, thus belonging to the same collection series at G and P. However, the specimen at K corresponds to Acalypha lamiana (Leandri) I.Montero & Cardiel, a species distinctly different from A. inaequibracteata. The original label is on the specimen at G and the specimens were distributed from there, so the K specimen is most likely mislabelled.