Cremastosperma R.E.Fr.

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

Cremastosperma R.E.Fr. Fig. 4 (Map 1)

Cremastosperma R.E.Fr., Acta Horti Bergiani 10: 46, f. 6 a–c. 1930.

Type.

Cremastosperma pedunculatum (Diels) R.E.Fr.

Description.

Trees or shrubs (0.5 –)1.5– 20 m tall; young twigs and petioles glabrous to densely covered with appressed or erect, simple, whitish to golden, up to 1 mm long hairs. Leaves distichous, simple, entire, petiolate, exstipulate; lamina elliptic to obovate or narrowly so, index 1.6-5, chartaceous to coriaceous, glabrous (rarely sparsely covered with appressed or erect, simple, up to 1 mm long hairs) above, glabrous to densely hairy (particularly at the base and on veins) below, base acute, obtuse or rounded, rarely subcordate to cordate, apex acuminate, sometimes caudate, rarely obtuse to acute, extreme tip rounded, venation brochidodromous, primary vein raised over entire leaf length above with an often conspicuous longitudinal groove particularly in the basal half, secondary veins 5 –20(– 30) on either side of the primary vein, often with 1-6 intersecondary veins, running parallel to primary vein for a short distance, thereafter angles with primary vein either increasing or decreasing towards the apex (or consistent), sometimes branching, often forming distinct loops, smallest distance between loops and margin 1-7 mm, tertiary veins percurrent (or reticulate). Inflorescence of single flowers or occasionally up to 8 in a rhipidium, pendant, clustered in groups of up to 7, terminal on short axillary shoots (i.e. peduncles) on leafy or leafless twigs, older branches or on the main trunk (then often on brachyblasts); 1-several lower bracts, deltate to depressed ovate, rarely narrowly elliptic, leafy, rounded to acute, soon falling off or persistent; single upper bract attached to pedicel, ovate to deltate, acute to obtuse; flower buds open or closed in development, when closed (ovoid to triangular) broadly to depressed ovoid; peduncles, pedicels, outer sides of bracts, sepals and petals glabrous to densely covered with appressed or erect, simple, up to 1 mm long hairs, bracts, sepals and petals ciliate. Flowers actinomorphic, bisexual, with one whorl of free or slightly connate, imbricate, sepals and two whorls of free, imbricate, petals, green, creamy or yellow in vivo, often black in sicco; sepals and petals thin at margins, occasionally with prominent venation; sepals three, much smaller than petals; petals six, the outer ones ovate, elliptic or broadly so, the inner ones elliptic to obovate or narrowly so, stamens numerous (ca. 100), spirally arranged, extrorse, inserted on and below a ventral ridge encircling a central depression in the receptacle in which the carpels are inserted, 1-2 mm long, connective appendage transversely rhombic-hexagonal; carpels 20-40, spirally arranged, free, ovary 1-locular, glabrous or hairy, with 1 basal, lateral or apical ovule (reported by Van Heusden 1992), stigma sessile. Fruit apocarpous, monocarps 5-40, stipitate, mostly asymmetrical, sometimes strongly so, sometimes with an (often excentric) apicule, green maturing mostly through red to brown or black in vivo, light brown to black in sicco. Seeds 1, lateral or apical (reported by Van Setten & Koek-Noorman 1992), ellipsoid to globose, yellow to reddish-brown, surface deeply to shallowly pitted, lacking an aril, with a raised or sunken raphe encircling seed longitudinally (diagonally), regularly (or more sinuously), ruminations spiniform.

Distribution.

34 species in the Neotropics: from southern Costa Rica in the north to Bolivia in the south. Most species are distributed in regions surrounding the Andean mountain range, two in coastal Venezuela ( Cremastosperma macrocarpum Maas and C. venezuelanum Pirie), one in French Guiana ( C. brevipes (DC.) R.E.Fr.) and one widespread across Brazil, south of the Amazon River ( C. monospermum (Rusby) R.E.Fr.).

Habitat and ecology.

Lowland to premontane tropical wet forest, inundated areas and terra firme. At elevations of 0-2000 m. Flowers and fruit of species of Cremastosperma appear similar in overall morphology and ontology to those of other Annonaceae demonstrated or presumed to be beetle-pollinated and/or bird-dispersed. We have observed in various species that the inner petals form a loose pollination chamber when mature, similar to that observed in, for example, Guatteria ( Gottsberger 1970); and flowers of Malmeoideae genera in general are visited at least predominantly by small beetles ( Saunders 2012). Similarly, we have observed in various species that the fruits become fleshy at maturity and often present a colour contrast between, for example, black monocarps and bright red stipes, representing a classic bird/monkey dispersal syndrome ( Gautier-Hion et al. 1985). However, we are unaware of detailed studies of either pollination biology or seed dispersal in species of Cremastosperma .

Figures

Figure 4. Distribution map of Cremastosperma showing the four disjunct areas of the distribution: 1 the Choco / Darien / western Ecuador region north into Central America 2 the tropical Andes (including a rough demarcation between areas occupied by northern / lowland and southern / montane clades) 3 coastal Venezuela 4 French Guiana.