Coffea sambavensis

Davis, Aaron P. & Rakotonasolo, Franck, 2001, Two new species of Coffea L. (Rubiaceae) from northern Madagascar, Adansonia (3) 23 (2), pp. 337-345 : 340-344

Coffea sambavensis J.-F. Leroy ex A.P. Davis & Rakotonas., sp. nov.

Coffeae millotii J.-F. Leroy affinis sed ramulis apicem versus albidis (nec brunneis), venis lateralibus (venis secundariis) foliorum 6-8-jugis [nec (6-)8-10- jugis], lamina in superficie abaxiali laevi (nec rugosicoriacea), domatiis in superficie abaxiali prominentibus (nec obscuris) etiam in superficie adaxiali manifestis (nec invisibilibus), a costa distantibus 2.5-8 mm (nec juxta costam) positis, distinguenda.

TYPUS. — Capuron 27706-SF, Madagascar, Est ( Nord ): forêt littorale , au Sud de Sambava , 1-10 Apr. 1967, fr. (holo-, P!; iso-, K!, TEF!) .

Small tree, 4-8 m high, dbh 4-16 cm. Bark whitish to grey, slightly rough to rough and peeling in patches c. 7 cm in diam. Branches terete to 4-angled, 5-8 mm in diam., grey to whitish, or brown, smooth, sometimes soft and peeling. Branchlets terete to 4-angled, 2.5-5 mm in diam., white to brown, usually soft and spongy with freely peeling bark, sometimes with many small, black dots (?lenticels or?asci). Stipules caducous, ovate to broadly ovate or ± deltate, 2.2-3 × 3.5- 4.2 mm, subcoriaceous, glabrous, margin glabrous; apex obtuse to acute.

Leaves: petioles 0.9-1.5 cm long; leaf-blades broadly ovate to ovate-orbicular, obovate-orbicular, broadly obovate, or oblong-obovate, (5.2-)8- 9.7(-10.5) × (2.2-) 3.5-7.7 cm, subcoriaceous; base attenuate; margins subrevolute to revolute; apex rounded to obtuse, often subacuminate; abaxial surface: midrib prominent; secondary veins prominent, 6-8 pairs, ascending at an angle of 30° to 45°, straight to curved, joining to form a hooped intramarginal vein, with a second intramarginal nearer the margin; tertiary venation manifest to prominent, ± reticulate; higher order venation obscure, ramified; adaxial surface: venation manifest more clearly than that of the abaxial surface; domatia crypt type, few but conspicuous, located 2.5-8 mm from the midrib usually along the secondary veins, orifice 0.1- 0.3 mm in diam., or domatia becoming necrotic and orifice 0.4-10 mm in diam., margin slightly raised, or swollen and chartaceous, glabrous; prominent on adaxial surface, manifest as small, elliptic pustules, 1.5-3.5 × 1-1.2 mm, these sometimes darker than leaf surface.

Inflorescence 1 per leaf axil, 2-4(-6)-flowered, ± umbellate, very shortly branched, with 1 short branch at base (0.2-0.3 mm long), 5-6 mm long, elongating considerably during fruit development, often slightly covered with exudate; inflorescence axis (bearing calyculi) 4.5-6.5 mm long. Calyculi 3, the basal and lower calyculus often falling or broken, ± sessile, subcoriaceous, glabrous to puberulous, margins glabrous or with few hairs (0.2-0.3 mm long); basal (1 st) calyculus 1.8-2.2 × 2.4-3.6 mm, stipular lobes 1.7-2 × 1.6- 2.7 mm, foliar lobes not seen; middle and upper (2 nd and 3 rd) calyculi (2.5-)4.3-5.5 × (3.2-) 4.9- 12 mm, stipular lobes broadly ovate to ± deltate, (2-)3-5.2 × 3-5 mm, foliar lobes elliptic to obovate, distinctly smaller than stipular lobes, 1-1.5 × 0.3-0.5 mm; internal surfaces of calyculi and with many colleters, particularly at the base, intermixed with numerous fine hairs (0.2- 0.3 mm long); colleters narrowly conical to very narrowly ellipsoid, c. 0.2 mm long, white.

Flowers 5-merous; pedicel 2-5.5 mm long, without bractlets. Calyx (hypanthium) ± obconical to campanulate, 1.8-2.3 × 1.8-2.4 mm, glabrous, smooth; calyx limb very shallowly 5- lobed to truncate, shorter than the disc; disc rather prominent, ± discoid. Corolla 15-17 × 11- 14 mm, corolla tube slightly longer than corolla lobes, smooth; corolla tube ± broadly funnelshaped, 9-11 mm long; corolla lobes 6-8 × 4.7- 6 mm. Stamens: filaments infradorsifixed, 4-4.5 mm long; anthers narrowly elliptic to linear, c. 6 mm long. Style 15-16 mm long; stigma lobes 2.5-3 mm long.

Fruit (immature), shortly obovoid to ± turbinate, 17-22 × 14-18 mm, slightly bilobed to bilobed (upon drying), shrinking considerably upon drying, green; fruit wall 3.5-4 mm thick; pedicel (6-) 9-13 mm long; calyx limb inconspicuous. Seeds (immature) ± ellipsoid to ellipsoidobovoid, 14-16 × 9-12 mm, c. 7 mm thick, white (fresh) to light brown (when dry). — Fig. 3.

DISTRIBUTION. — Endemic to north-eastern Madagascar, in the Antsiranana Province; between Sambava and Vohimarina (Vohémar). — Fig. 2.

HABITAT & ECOLOGY. — Lowland humid evergreen forest, including the littoral zone. On loose sands, basement rocks and lavas. Altitude 0-200 m.

PHENOLOGY. — Flowering in November; probably fruiting in April. Phenology of cultivated material not included.

CONSERVATION STATUS. — IUCN Red List Category: Endangered (EN B1 a,b). B1 — total extent of occurrence less than 1000 km 2 (c. 350 km 2); a. — severely fragmented, and possibly existing at no more than five locations; b(i-v). — continuing decline inferred. There are no populations of C. sambavensis within the current scheme of protected areas. Fieldwork in areas of remaining primary forest (including degraded primary forest) near Sambava, and along the coast of north-eastern Madagascar, is required for a more confident assessment of extinction risk.

PARATYPES. — NE MADAGASCAR, Antsiranana: Capuron 24928-SF, district Est ( Nord ): forêt littorale , au Sud de Sambava , 20 Oct. 1966, fl. bud ( K, P, TEF); Davis & Rakotonasolo 2346 (Kianjavato acc. no. 955), Sambava , recollected from the Coffee Research Station at Kianjavato (FOFIFA), recollected 28 Nov. 1999, fl. ( K, P, TAN); Davis & Rakotonasolo 2323 (Kianjavato acc. no. A. 950), ibid., recollected 27 Nov. 1999, fl., fr. ( BR, K, P, MO, TEF); Rakotonasolo RNF 270, Vohémar , Fanambana , 190 m, 24 Nov. 2000, fl. bud. ( K, P, MO, TAN, TEF); Rakotonasolo RNF 274, Sambava , Anjangoveratra , Ambodisambalahy , 26 Nov. 2000, fl. ( K, TAN, TEF) .

Coffea sambavensis is an easily recognized species due to following combination of features. The branches are normally whitish, usually with a soft, peeling bark. The leaves are broad (length to width ration 3:2, or greater), subcoriaceous, and have prominent domatia. The domatia are not located against the midrib but several millimetres away from it, along the secondary veins, and they are often visible on the adaxial surface (see Fig. 3A,B ). The fruit is rather large, thickwalled (mostly mesocarp), and born on long pedicels. The pedicels are short in flower but lengthen significantly during fruit development. See description for all measurements.

Coffea sambavensis most closely resembles C. millotii J.-F. Leroy, another species from the humid forests of eastern Madagascar. Coffea millotii is similar to C. sambavensis in fruit and inflorescence morphology, but is easily separated because the domatia are located against the midrib, and the abaxial surface of each leaf is rough and wrinkled (smooth in C. sambavensis ). The colour of the branchlet bark, and the number of pairs of secondary veins are other features that can be used to separate these species, as given in the diagnosis above. The distribution of C. millotii does not overlap with C. sambavensis , as its northern limit of distribution is in the Masoala Peninsula, which is some distance south of Sambava.

Figures

Fig. 3. — Coffea sambavensis J.-F. Leroy ex A.P. Davis & Rakotonas.: A, habit; B, domatia (adaxial view); C, inflorescence, with calyculi (corollas and styles fallen); D, flower; E, flower dissection; F, fruit; G, transverse section of fruit. A, B, Capuron 27706-SF; C-G, Davis & Rakotonasolo 2323.