Cremastosperma osicola Pirie & Chatrou, 2018

Pirie, Michael D., Chatrou, Lars W. & Maas, Paul J. M., 2018, A taxonomic revision of the Neotropical genus Cremastosperma (Annonaceae), including five new species, PhytoKeys 112, pp. 1-141 : 1

25. Cremastosperma osicola Pirie & Chatrou sp. nov. Figs 23 , 34 , Map 2

Diagnosis.

Differs from C. megalophyllum , C. pacificum and C. yamayakatense in the fully open bud development; from C. brevipes , C. magdalenae , C. novogranatense , C. pacificum and C. westrae in the stipes being longer than the monocarps and (except C. magdalenae ) in the usually much larger number of monocarps (20-40 as opposed to mostly fewer than 20); from C. westrae and C. novogranatense in the absence of indument on the fruits; from C. panamense in the greater size of the fruits and the shape of the monocarps (ellipsoid, compared to more or less globose in C. panamense ); and from all of the above except C. novograntense in the much larger flowers.

Type.

COSTA RICA, Puntarenas: Cantón Osa, Distr. Sierpe, Los Mogos, Bahia de Chal, Entrada San Juan, 9 Sep 2011, Chatrou, L.W. et al. 707 (holotype: CR!; isotypes: K!, MO!, P!, U!).

Description.

Tree 3-7 m tall, 5-7 cm diam.; young twigs and petioles very sparsely covered with appressed whitish hairs to 0.2 mm long or glabrous. Leaves: petioles 7 –15(– 20) by 2-4 mm; lamina obovate to elliptic or narrowly so, 21-44 by 5-15 cm (index 2.6-3.4), chartaceous, green or brown above and below, veins darker below, glabrous above, very sparsely covered with appressed whitish hairs to 0.2 mm long, especially on veins or glabrous below, base acute or obtuse, apex acuminate (acumen 10-20 mm long), primary vein shallowly grooved near base, 1.5-2 mm wide at widest point, secondary veins 7-10, intersecondary veins 0-1, distance between from 10-13 mm at the base to 25-45 mm closer to the centre, angles with primary vein from 45-60° at the base to 70-80° closer to the centre, sometimes branching, forming distinct loops in apical half of leaf, smallest distance between loops and margin 2-3 mm, tertiary veins mostly percurrent. Inflorescence of single flowers solitary on leafless twigs or clustered in groups on brachyblasts on the main stem; peduncles 4 by 4 mm (in fruit); pedicels 18-23 by 3 mm at the base, 3-4 mm at the apex (in fruit), peduncles and pedicels glabrous; lower bract(s), upper bract and closed flower buds not seen, flowers (observed from photo: Fig. 21 o ) cream in vivo; sepals not seen; petals indument not seen, outer petals elliptic, ca. 31 mm long, inner petals elliptic, ca. 27 by 9 mm; androecium ca. 7 mm diam., stamens not seen; gynoecium ca. 2 mm diam., carpels not seen. Monocarps 20-43, ellipsoid (broadly so in immature specimens), slightly asymmetrical, 11-17 by 11-12 mm, green maturing to yellowish, orange and purple in vivo, black in sicco, with a small excentric apicule, monocarps, stipes and receptacle glabrous; stipes 17-30 by 1.5-2 mm; fruiting receptacle ca. 14 mm diam. Seeds ellipsoid, reddish-brown, shallowly pitted, ca. 12 by 10 mm, raphe sunken, regular.

Distribution.

Costa Rica (Puntarenas, Osa peninsula).

Habitat and ecology.

Tropical wet forest. At elevations of 40-300 m. Fruiting: July and September.

Notes. The distribution of Cremastosperma osicola in Costa Rica is the furthest north into Central America of any species of the genus. The species is most similar to C. pacificum , from the Pacific coast of Colombia, from which it can be discerned with flowering material by the much larger flowers (outer petals ca. 31 mm compared to ca. 16 mm in C. pacificum ) and with fruiting material by the length of the stipes exceeding that of the monocarps.

Preliminary conservation status.

Cremastosperma osicola is known from a small number of populations within a region sufficiently small to qualify it as Endangered, but within a protected area (Golfo Dulce Forest Reserve). Near Threatened [NT] (Table 1 ).

Other specimens examined.

COSTA RICA. Puntarenas: Osa, Golfo Dulce Forest Reserve, 8°40'N, 83°31'W, 40-100 m a.s.l., 25 Sep 1991, R.Aguilar 467 (INB, MO); Cantón de Osa, 8°43'20"N, 83°26'40"W, 20-100 m a.s.l., 13 Nov 1995, R. Aguilar et al. 4371 (INB); Osa, Bahia Chal-La Palma road, 8°44'N, 83°26'W, 80 m a.s.l., 29 Nov 1998, Chatrou et al. 103 (U); Osa, Rancho Quemado, near Rincón, 8°42'N, 83°33'W, 300 m a.s.l., 11 Jan 1993, Gentry et al. 78657 (F, INB, MO); Osa, Parque Nacional Corcovado Cerro Brujo, 8°39'00"N, 83°35'50"W, 617 m a.s.l., 19 Jul 1990, G. Herrera et al. 3972 (INB); Osa, Parque Nacional Corcovado Sirena, 8°28'N, 83°35'W, 1 50 m a.s.l., 20 Jul 1989, Kernan 1224 (U); Osa, Golfo Dulce Forest Reserve, 8°42'N, 83°25'W, 100 m a.s.l., 2 Jul 1984, Schatz et al. 1002 (MO, U, WIS); Osa, Golfo Dulce Forest Reserve, 8°43'N, 83°26'W, 20 m a.s.l., 24 Jul 1995, Zamora & R. Aguilar 2312 (INB, U).

Figures

Map 2. Distribution of Cremastosperma alticola Pirie & Chatrou, C. antioquense Pirie, C. chococola Pirie, C. dolichopodum Pirie & Maas, C. longipes Pirie, C. novogranatense R. E. Fr., C. osicola Pirie & Chatrou, C. panamense Maas and C. stenophyllum Pirie

Figure 21. Cremastosperma gracilipes R. E. Fr. a fruiting specimen b flower (a Hurtado 3019 b Palacios 1651).

Figure 23. a, b Cremastosperma leiophyllum R. E. Fr. a flower b fruit (Pirie et al. 2; photo LWC) c, d Cremastosperma megalophyllum R. E. Fr. c habit (Maas et al. 8577, photo: PJMM), fruit (Maas et al. 8595, photo PJMM) e-g C. microcarpum R. E. Fr. e fruit (Maas et al. 6281; photo PJMM) f, g flower (Maas et al 8222; photo PJMM) h-j C. monospermum (Rusby) R. E. Fr. h habit i leaves j flower bud (Pirie et al. 5; photos LWC) k, l C. oblongum R. E. Fr. k flower l fruit (Maas et al. 9148; photos PJMM) m-o C. osicola. m fruit n flower o leaf and flower with scale bar (photos Reinaldo Aguilar).

Figure 34. Cremastosperma osicola Pirie & Chatrou fruiting specimen (Aguilar 467).