Psychotria palifera C.M. Taylor, 2020

Taylor, Charlotte M., Gereau, Roy E. & Schmidt, Heidi H., 2020, Some distinctive new species of Psychotria (Rubiaceae, Psychotrieae) from Madagascar, Candollea 75 (2), pp. 159-182 : 178-180

Psychotria palifera C.M. Taylor , sp. nov. ( Fig. 5F–K , 7 ).

Holotypus: MADAGASCAR. Reg. Analanjiforo [Prov. Toamasina] : Ambatondrazaka , Réserve Naturelle Intégrale de Zahamena , 15–20 km au SE d’Ambarifotsy, Rivière d’Ihofika , 17 °39'46"S 48°59'05"E, 560 – 630 m, 27.V.2003, Andrianjafy et al. 368 ( MO-5789365 !; isotype: TAN) .

Psychotria palifera C.M. Taylor is distinguished from its congeners by its relatively large stipules with a distinctive shape in bud, along with the combination of its obovate, domatiate leaf blades that are subtruncate to shallowly retuse at the apex, relatively short, fasciculate, rounded inflorescences that often become overtopped by stem growth from both axils, and well developed lobed calyx limbs; the stipules of this new species are fused around the stem in the basal part into a tubular sheath and in the upper portion free, obovate, acute to acuminate or bidenticulate, and with dense longitudinal veins or fibers.

Shrubs and small trees, collected in flower variously at 6–12 m tall, branched; stems weakly flattened becoming terete, glabrous. Leaves opposite; petiole 5–30 mm, glabrous; blade obovate, 5–18 × 2.8–11.5 cm, at base cuneate to obtuse, at apex subtruncate to shallowly retuse then abruptly acuminate with tip 1–3 mm, drying papyraceous to chartaceous, on both surfaces glabrous and weakly shiny; secondary veins 6 to 12 pairs, looping to interconnect near margins at least in apical part of blade, without intersecondary veins or usually with 1 intersecondary vein present between pairs of secondary veins, with regularly developed crypt domatia, adaxially venation plane or costa and sometimes secondary veins prominulous, abaxially costa and secondary veins prominent and remaining venation plane. Stipules fused around stem, caducous, glabrous on both surfaces, sheath portion cylindrical, 3–12 mm, free upper portion ovate, 5–15 mm, with dense longitudinal fibers or veins, acute to acuminate or bidenticulate. Inflorescences terminal, cymose, with cymes borne on fasiculate axes, the group of axes sessile to subsessile, glabrous to densely pilosulous with trichomes 0.1–0.2 mm; flowering-bearing portion rounded-corymbiform, 3–6 × 4–8 cm, branched to 2 or 3 orders, c. 30- to 60-flowered; bracts reduced or broadly triangular, 0.1–0.5 mm, acute; pedicels 0.5–1 mm. Flowers all pedicellate in dichasial cymes of 5 to 9, 5-merous; hypanthium obconic, c. 0.8 mm, glabrous; calyx limb 1–1.2 mm, glabrous, denticulate or lobed to 1/3 of its length, lobes triangular, acute to obtuse; corolla funnelform, yellow, externally glabrous, tube c. 3.5 mm, c. 1.5 mm in diam. near middle, internally densely pilose in upper part with trichomes c. 1 mm, lobes ligulate to triangular, c. 2 mm, obtuse, adaxially shortly galeate, abaxially smooth; stamens inserted in upper part of corolla tube, filaments not seen, anthers c. 0.8 mm, included or partially exserted, positioned with tips at top of corolla tube; style c. 4 mm, stigmas c. 1 mm. Infructescences similar to inflorescences or often markedly overtopped by growth from subtending axils. Fruits subglobose, c. 5 mm diam., glabrous, red, with calyx limb 1.5–4 mm, lobed for 1/4–1/2 of its length; pyrenes 2, hemispherical, adaxially plane, abaxially smooth; endosperm densely deeply ruminate on both surfaces.

Etymology. – The profile shape of the stipules in bud resembles a spade, and the specific epithet refers to that implement.

Habitat, distribution and phenology. – Psychotria palifera has been collected in humid evergreen forest at 560–1100 m in central eastern Madagascar (Toamasina), with flowers in March and with fruits in May and June .

Conservation status. – Psychotria palifera is known from ten specimen collections representing nine unique occurrences in humid evergreen forest at 560–1100 m elevation. The EOO of the species is 2,716 km ², within the limits for “Endangered” under IUCN Red List Criterion B1; and the AOO is 36 km ², also within the limits for “Endangered” under Criterion B2 ( IUCN, 2012). Six of the collection sites are within two protected areas: Zahamena PA (two sites), with a good protection level; and Ankeniheny-Zahamena Corridor PA (4 sites), with the interior of the reserve well protected but parts close to villages seriously impacted by exploitation of timber and, to a lesser extent, shifting cultivation (C. Birkinshaw, pers. comm.). The remaining three collection sites are in unprotected areas: one to the east of Ankeniheny-Zahamena Corridor PA and c. 4 km west of Betampona PA (forêt secondaire de Sondrimaro); one c. 200 m outside Ankeniheny-Zahamena Corridor in secondary forest (Ambodivoromborogna Forest); and the third c. 11 km east of the southernmost parcels of AnkenihenyZahamena Corridor PA. This distant collection is from 1975 in an area with no protection, near a major roadway; it very likely that the population no longer exists at this collection site. The loss of this site would significantly decrease the EOO for this species as well as the AOO. Forested areas without formal protection in the vicinity of these protected areas are subject to degradation by small-scale slash and burn agriculture and fire to create habitat for cattle farming as well as resource exploitation including logging, hunting and mining ( GOODMAN et al., 2018). All three of the unprotected collecting sites would be subject to such threats. The northernmost two collections are within Zahamena PA, and constitute a single “location” (sensu IUCN, 2012, 2019). Three collections are from the northernmost parcel of Ankeniheny-Zahamena Corridor adjacent to Zahamena PA, and constitute a second location. One collection is from forêt d’Ambatoaragnana, AnkenihenyZahamena Corridor PA and constitutes a third location. Each of the three widely separated unprotected sites constitutes a separate location, giving a total of six locations. Three locations are in generally well-protected areas, but the other three are in vulnerable areas, one of which may already be lost, causing a decline in EOO and AOO, extent and/or quality of habitat, number of locations and number of mature individuals. Thus, the Red List status of P. palifera is assessed as “Vulnerable” [VU B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)].

Notes. – Psychotria palifera is characterized by the combination of its relatively robust habit for its genus; glabrous vegetative structures; medium-sized obovate leaf blades with small domatia in the abaxial axils and the apices truncate to shallowly retuse; distinctive large stipules; relatively short, fasciculate, corymbiform inflorescences that often become overtopped by growth from both subtending axils; welldeveloped lobed calyx limbs; medium-sized fruits; pyrenes that are smooth abaxially; and endosperm that is reticulate on both surfaces. The specimens dry with a dark brown color, which is also seen in the sapwood of cut stems. The stipules of P. palifera are unusually well developed and distinctive in form: these are fused in their basal portions into a cylindrical sheath, then the upper parts are ovate, venose or fibrose, and initially pressed flat together with their margins rolling back. These stipules also vary markedly in size, from smaller ones on terminal buds of stems with young leaves to those that are mature and dehiscing. These stipules are similar in form to those of P. hamifera , newly described above. Only one fully developed flower has been seen, and was not dissected in order to preserve it; it agrees with the long-styled form of distylous Psychotria species , but whether P. palifera is distylous cannot be determined. The infructescences are relatively short and have a characteristic form that is commonly seen in Psychotria , with the flowers borne in groups on several axes, and these axes then arising from a node that either bears developed leaves, or bears an internode that is hardly developed (1–2 mm long) and then another node that bears bracts and the axes. This arrangement was analyzed in detail by TAYLOR (2020), who noted that it is part of continuous variation in inflorescence form in this genus, and its interpretation as pedunculate vs. subsessile or fasciculate depends on the degree of development of the leaf-like structures borne from the subtending node: if these are small they are considered bracts and the inflorescence pedunculate, while if they are enlarged and green they are considered leaves and the inflorescence sessile to subsessile and fasciculate. In P. palifera the inflorescences seen are subtended by developed leaves, and are also overtopped or enclosed by leafy stems that develop form one or usually both of the axils of the subtending leaves. The development of a reduced internode just above the leaves that subtend the inflorescence is variable in P. palifera , so it is sometimes evident and sometimes apparently did not develop. The calyx limb appears to enlarge as the fruit develops, to almost twice its size at anthesis, but the flowers are not well enough documented to confirm this. This species agrees with BREMEKAMP (1963) ’s Mapouria Group VII. A fruiting specimen is is chosen as the type because most of the characters that contrast it with the similar species Bremekamp treated are in the fruits and seeds.

Psychotria palifera is similar to P. imerinensis (Bremek.) A.P. Davis & Govaerts and P. manampamihensis (Bremek.) A.P. Davis & Govaerts , which both can be separated by their shorter ligulate to ovate stipules, 2–5 mm long, and their shorter, truncate to denticulate calyx limbs, 0.5–1 mm long, and they also often differ by their narrower leaf blades, 1.2–6 cm wide.

Paratypi. – MADAGASCAR. Reg. Analanjirofo [ Toamasina ]: Ambatondrazaka , RN Zahamena , 17°39'46"S 48°59'05"E, 560– 360 m, 27.V.2003, Andrianjafy et al. 371 ( CNARP, MO, P, TEF); Vavatenina , à 10 km au N d’Anamborano, 17°42'04"S 49°00'48"E –17°42'04"S 49°00'48"E, 620 m, 12.VI.2004, Andrianjafy et al. 436 ( CNARP, MO, P, TEF); PN Zahamena , 17°33'30"S 48°53'35"E, 800 m, 5.V.2003, Rakotonandrasana 688 ( CNARP, MO, TEF); sine loco, 17°41'27"S 48°59'52"E, 13.VI.2001, Randrianjanaka et al. 611 ( CNARP, MO, P, TEF); Miarinarivo-Anamborano , Ambinanisavaharina , 17°41'15"S 49°00'02"E, 580–620 m, 14.VI.2001, Ratovoson et al. 492 ( CNARP, MO, P, TEF); Atsinanana , along rte # 2 , 41 km E of Perinet, [18°55'00"S 48°37'00"E], 600 m, 1.III.1975, Croat 32639 ( MO); Toamasina II , Sahambala , Sahavongo , forêt d’Ambodivoromborogna , 18°01'41"S 49°05'37"E, 608 m, 20.V.2017, Ralaijaona & Syde 159 ( K, MO, P, TAN); forêt d’Ambatoaragnana , 18°01'31"S 49°04'59"E, 675 m, 21.V.2017, Rasoanindriana et al. 169 ( K, MO, P, TAN); Ambodirafia , proche Lohanifotsy , 17°52'54"S 49°09'56"E, 452 m, 20.VI.2017, Rasoanindriana et al. 201 ( BR, K, MO, P, TAN) .

Figures

Fig. 5. – Psychotria hamifera C.M. Taylor: A. Fruiting branch; B. Stipule at stem apex; C. Hypanthium and calyx limb of flower; D. Corolla at anthesis; E. Cross-section of pyrene and seed. Psychotria palifera C.M. Taylor: F. Fruiting branch; G. Stem apex with bases of two petioles and young stipules; H. Stem apex with bases of two petioles and older stipules; I. Portion of inflorescence with two flowers from which corollas have fallen and one flower bud; J. Corolla at anthesis; K. Cross-section of pyrene and seed. [A: Antilahimena 1778; B–D: Antilahimena 1594; E: Antilahimena 2657; F, K: Andrianjafy 368; G: Rasoandriana 169; H: Andrianjafy 371; I–J: Croat 32639]

Fig. 7. – Psychotria palifera C.M. Taylor. [Rasoanindriana et al. 169] [Photo: S.E. Rakotoarisoa]