Siparunaceae

References: TULASNE, L. R., Monographia Monimiacearum primum tentata. Arch. Mus. Hist. Nat. 8: 273-436, pl. 25-34 (1855);

Monographia Monimiacearum. In: C. F. P. VON MARTIUS (ed.), Flora brasiliensis 4(1): 289-328, pl. 82-86 (1857). - PERKINS, J. R., Beiträge zur Kenntnis der Monimiaceae. III. Monographie der Gattung Siparuna. Bot. Jahrb. 28: 660-705, t. 12-14 (1901); Monimiaceae (Nachträge). Pflanzenreich, Suppl. IV, 101: 1-67 (1911). - ENDRESS, P. K., Ontogeny, function and evolution of extreme floral construction in Monimiaceae. Pl. Syst. Evol. 134: 79-120 (1980). - FEIL, J. P., Reproductive ecology of dioecious Siparuna (Monimiaceae) in Ecuador - a case of gall midge pollination. Bot. J. Linn. Soc. 110: 171-203 (1992). - RENNER, S. S., SCHWARZBACH, A. E., & LOHMANN, L., Phylogenetic position and floral function of Siparuna (Siparunaceae: Laurales). Intern. J. Plant Science 158: S89-S98 (1997). - RENNER, S. S., Circumscription and phylogeny of the Laurales: evidence from molecular and morphological data.  Am. J. Bot. 86: 1301-1315.

Evergreen, often sarmentose shrubs, treelets, or trees with spherical oil cells in all parts of the plants. Leaves decussate or in whorls of 3-6, simple, exstipulate, those of a pair occasionally unequal in size, with stellate, lepidote, or simple hairs, the margin variously serrate, dentate, or entire. Inflorescences axillary or cauliflorous, cymose, sometimes fasciculate. Flowers typically radial, strictly unisexual, plants dioecious or more rarely monoecious, floral cup (receptacle) well developed (the perigon perigynous), subglobose or cup-shaped, tepals 4-6 (rarely 7), usually minute or fused to a rim encircling the floral cup, rarely one tepal much longer than the others (in the African Glossocalyx) or tepals forming a calyptra, the flower centre more or less covered by a membrane (called floral roof or velum) except for a central pore through which stamens or styles may emerge; stamens (1-) 2-70, dispersed irregularly in the floral cup, filaments lacking appendages, anthers with 2 closely adjacent apical pollen sacs opening by a single flap (valve) or very rarely by two flaps; carpels free but the styles sometimes postgenitally fused, 3-30, sessile and completely immersed in the floral cup, ovules solitary, basally attached and anatropous, unitegmic, crassinucellate. Fruit consisting of the fleshy receptacle which at maturity splits irregularly to expose (1-) 3-25 small drupelets with a conspicuous red or orange aril (in the neotropical species), the endocarp stony.

The Siparunaceae comprise 2 genera, the neotropical Siparuna with at least 70 species from Mexico and the West Indies to Paraguay and Argentina and the West African Glossocalyx, with one species, G. longicuspis Benth., in Cameroon, Gabon, and the island of Fernando Pó. The family is sometimes included in the Monimiaceae but is more closely related to other lauralean lineages, especially the Gomortegaceae and Atherospermataceae, than it is to the Monimiaceae sensu stricto, a group of 22 poorly circumscribed genera, including Monimia, Tambourissa, Hedycarya, Peumus, and - in Ecuador - Mollinedia. Siparuna is readily distinguished from Mollinedia by having pollen sacs opening by valves (vs. longicidally), drupelets enclosed in the fleshy floral cup until maturity (vs. drupes exposed throughout their maturation), a conspicuous orange or red aril atop each drupelet (vs. drupes lacking an aril), and several embryological features, such as basally attached ovules (vs. pendant ovules) and integuments with one integument (vs. ovules with two integuments).

Siparuna AUBLET

Hist. Pl. Guiane Française: 864 (1775). - Type: Siparuna guianensis AUBLET.

Citrosma RUIZ & PAVÓN, Fl. Peruv. Chil. Prodr. 134 (1794); Citriosma TUL., orth. var.

Conuleum A. RICH., Mém. Soc. Hist. Nat. Paris 1: 391 [name], 406 [descr.], pl. 25 (1824).

Dioecious or monoecious sarmentose shrubs, treelets, or trees to 40 m high, aromatic due to abundant quantities of volatile oil in oil cells throughout the plant, sparsely or densely pubescent, the hairs stellate, stellate-lepidote, lepidote, or simple, older leaves sometimes glabrous. Leaves decussate or in whorls of 3, 4, or 6, petiolate, the margin dentate, serrate, or entire. Cymes unisexual or bisexual, axillary and/or on leafless nodes. Flowers radial, strictly unisexual, pedicellate, the floral cup subglobose or cup-shaped, rarely urceolate or flask-shaped, completely enclosing the stamens or carpels except for a variably-sized pore in the centre through which the styles or stamens may protrude, the 4-6(-7) tepals minute, triangular, rounded, or spatulate, or forming a rim encircling the floral cup or a calyptra (S. decipiens), the flower centre covered by a slightly or strongly raised and variously differentiated floral roof (velum); stamens usually 5-9, occasionally 1 or up to 70, free, rarely concrescent, dispersed irregularly in the floral cup, with 2 closely adjacent apical pollen sacs opening by a single flap, rarely opening by two flaps, filaments short, stout, and flattened; carpels 3-30, free but the styles sometimes postgenitally fused, the stigmas papillose and decurrent. Mature floral cups fleshy and 1.5-3.5 cm in diam. (when dry), globose, smooth, spiny, or with short tubercles, rarely almond-shaped or with longitudinal ribs, often crowned by the persistent tepals, when fresh and mature reddish or rarely yellow and with a strong pungent scent, splitting irregularly from the apex and spreading to reveal 3-25 drupelets; the drupelets fresh bluish-grey and with an apical and/or lateral orange or red aril (Pls. 1, 3); the testa black and verrucose.

A genus of at least 70 species, distributed from Central America and the West Indies throughout northern South America to Paraguay and Argentina; 36 species are currently known from Ecuador, including two species awaiting description when complete material becomes awailable (Siparuna sp. A and B at the end of the present treatment). Sterile material of Siparuna can rarely be identified with certainty. Nine [10 are keyed out as monoecious in the key] of the Ecuadorean species are monoecious, and this breeding system in Ecuador is highly correlated with entire leaf margins.


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