Talinella bosseri Appleq., 2005

Applequist, Wendy L., 2005, A revision of the Malagasy endemic Talinella (Portulacaceae), Adansonia (3) 27 (1), pp. 47-80 : 58

4. Talinella bosseri Appleq. , sp. nov.

Haec species Talinellae humbertii Appleq. affinis, sed ab ea foliis (2.5-)5.0-10.0 cm longis anguste lanceolatis vel lanceolatis glabris nervis secundariis bene manifestis apice saepissime asymmetricis, inflorescentiis majoribus, squamis gemmae foliaris inconspicuis fuscatis deltoideis, sepalis (2.5-)3.0- 3.6 mm longis atque florum masculinorum petalis 3.5-5.0 mm longis bene convexis ac filamentis 2.5-3.0 mm longis differt.

TYPUS. — Bosser 17406bis, Prov. Fianarantsoa, route de Ranotsara, district d’Ihosy, vestige de forêt tropophile, c. 22°38’S, 046°30’E, fl., Feb. 1963 (holo-, P!).

Subshrub to 1 m high. Twigs straight, tan mottled with brown, papillose; papillae white and brown. Leaves narrowly lanceolate to lanceolate, (2.5-)5.5-10.0 cm long, (0.8-) 1.2-2.2 cm broad; apex narrowly acute, usually asymmetrical; base tapering, often somewhat rounded; margins entire; midrib fairly prominent, secondary venation visible but inconspicuous; both surfaces glabrous. Inflorescence terminal, loose, paniculiform; peduncle and rachis slender, glabrate; bud scales on subtending twigs few, deltoid, <1 mm long, mottled, usually not recurved; bracts 0.3-0.8(-1.4) mm long, narrowly triangular, red-brownish with or without pale margin, or pale with mottled brown. Probably dioecious. Pedicel 3-6 mm long. Sepals (2.5-)3.0- 3.6 mm long, broadly elliptical to broadly ovate, pale; apex obtuse. Petals 2, 3.5- 5 mm long, obovate, strongly hooded. Stamens up to 20; filaments pink, 2.5-3 mm long, the lower 40% of those of the inner whorl flattenedciliate; anthers yellow, 0.35-0.6 mm long; pollen yellow, released before flower is open. Female flowers and fruits unknown. — Fig. 5 .

Bosser 17406bis, the type of Talinella bosseri , collected southeast of Ihosy, was included within T. dauphinensis by EGGLI (1997), but it differs both by its unusual long, narrowly lanceolate leaves, often with an asymmetrical, narrowly acute apex, and by its flowers with two petals, equal sepals and stamens not reduced in number. It seems likely that this material is more closely related to T. humbertii , which also has two petals and frequently equal sepals. T. humbertii has smaller flowers with fewer stamens; its leaves are usually smaller and, if large, are not shaped like those of T. bosseri .

DISTRIBUTION. — Talinella bosseri is known only from a single locality in south-central Madagascar ( Fig. 6 ); the type was collected from a patch of forest on sand to the north of Ranotsara ( BOSSER pers. comm.) .

CONSERVATION STATUS. — Provisional IUCN Red List Category: Critically Endangered (CR B1ab(iii)+2ab(iii)). The area around Ranotsara and Ihosy is wholly unprotected and has suffered serious ecological degradation, so that only small patches of natural vegetation remain; a decline in area or quality of habitat has certainly occurred in the past and may be expected to continue in future. Efforts to relocate T. bosseri in the field were unsuccessful, although its vegetative appearance is distinctive.

Figures

FIG. 5. — Talinella bosseri Appleq.: A, habit; B, diagram of inflorescence; C, leaf (abaxial surface); D, male flower. Bosser 17406bis.

FIG. 6. — Distributions of Talinella dauphinensis and segregate species: T. bosseri ($), T. dauphinensis (N), T. humbertii (▲), T. latifolia (★), T. tsitondroinensis (✚).