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Published In: Annales des Sciences Naturelles; Botanique, série 4, 1: 73. 1854. (Feb 1854) (Ann. Sci. Nat., Bot., sér. 4,) Name publication detailView in Biodiversity Heritage Library
 
 

Project Name Data (Last Modified On 10/6/2016)
Acceptance : Accepted
Note : Tribe Condamineeae
Project Data     (Last Modified On 11/28/2020)
Notes:

Schizocalyx is a genus of 9 species of Neotropical trees and shrubs. This genus is characterized by its woody habit; opposite or verticillate, often robust leaves; caducous, calyptrate stipules (i.e., the stipules are fused into a conical cap) that usually split as the leaves emerge; terminal cymose inflorescences with bracts that are often also calyptrate; bisexual, homostylous, protandrous flowers; a calyx limb of various forms; campanulate to funnelform corollas with 5 lobes that are convolute in bud; and fruits that are small, woody, 2-locular capsules that open loculicidally across the top to release numerous small angled seeds. A detailed morphological description along with a key to the species was presented by Taylor et al. (2011). The calyx limb of some species is calyptrate, similarly to the stipules, or in other species it is open and variously truncate to lobed. In one species, S. bracteosus, the calyx limbs of some flowers bear an enlarged white petaloid lobe, or calycophyll, which is also persistent on the fruits. The corollas are mostly white or in a few species pale green to pink or pale purple, and the flowers are described by many collectors as fragrant. The small fruits are distinctive (though not unique) in dehiscing across the top portion, inside the ring of the calyx limb or its scar; seed dispersal is apparently via a "salt shaker" effect.

The identity and circumscription of Schizocalyx have not been clear until recently, when the morphology of the species was better documented and molecular study (Kainulainen et al. 2010) showed that two genera and several species that were classified in another genus, Bathysa, are in fact closely related to each other. In particular the identity and relationships of Phitopis were unclear for many years, due in part to an inaccurate description of its stipule morphology in the protologue; see the Phitopis page of this Rubiaceae project for more details. Schizocalyx was monotypic for many years, and distinguished by its petaloid enlarged calyx lobes; such structures are found in various genera in various tribes and subfamilies, and sometimes only in one or a few species of a genus. Schizocalyx bracteosus was included in the similar genus Bathysa by some authors based on its corolla lobes that are apparently imbricated in bud. However Bathysa, with and without the inclusion of Schizocalyx bracteosus, was heterogeneous morphologically and both morphology and molecular sequence data (Kainulainen et al. 2010) show that Schizocalyx bracteosus as well as several other species described in Bathysa are better separated. When these species are removed, Bathysa can be characterized well morphologically by its imbricate corolla lobes and septicidal capsules, though it retains two problematic species that not seem to belong to Schizocalyx.

The species of Schizocalyx that were included in Bathysa do have convolute corolla lobes, but this arrangement is very hard to discern in many cases because the lobes overlap only very thinly and the corollas of dried specimens often open prematurely and their corolla lobes arrangement is no longer clear. The pollination biology of Schizocalyx cuspidatus was studied by Freitas & Andrich (2013), who found the corolla opens at night and pollination appears to be nocturnal however the stigma is not receptive until morning and the amount of nectar is very small. They proposed that pollination of this species is by stingless bees consuming the pollen.

In a molecular systematic study Kainulainen et al. (2010) found Schizocalyx to belong to their Tribe Condamineeae, and related to Eleagia rather than Bathysa.

Author: C.M. Taylor
The content of this web page was last revised on 20 July 2020.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

Distribution: In wet vegetation or sometimes perhaps gallery forests, in lowland to montane habitats (0-2000 m), from Nicaragua to southeastern Brazil. Most of the species are found in the Andes and its eastern foothills.
References:

 

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Shrubs and trees, unarmed, terrestrial, without raphides in the tissues, often with well developsed hirsute or strigose pubescence. Leaves opposite or verticillate, subsssile or petiolate, with tertiary and quaternary venation not lineolate, without domatia; stipules caducous, fused into a calyptrate, splitting along 1--2 sides. Inflorescences terminal, cymose to thyrsiform, multiflowered, pedunculate or subsessile and tripartite, bracteate. Flowers sessile to pedicellate, bisexual, homostylous, protandrous, fragrant, apparently diurnal; hypanthium obconic to  turbinate; calyx limb developed, calyptrate and splitting irregularly or open, truncate to regularly 4--5-dentate, and sometimes with calycophylls; corolla funnelform to campanulate or tubular, white to pale green or flushed with pink or purple, internally glabrous except with tufted pubescence at stamen insertion that produces a barbate throat, lobes 5, triangular to ligulate, in bud convolute, without appendage; stamens 5, inserted in upper part of corolla tube, anthers narrowly ellipsoid-oblong, dorsifixed, opening by longitudinal slits, exserted, with apical appendage; ovary 2-locular, ovules numerous in each locule, on axile placentas, stigmas 2, ellipsoid to ligulate, exserted. Fruit capsular, subglobose to turbinate, loculiciidally dehiscent across apex, woody to chartaceous, smooth, with calyx limb persistent; seeds numerous, angled, small (0.2--0.5 mm), sometimes thinly winged, seed surface stratie to foveolate, wing when present entire. 

 

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 Key to Species of Schizocalyx; based on Taylor et al., 2011

1. Calyx limb 6-12 mm long, more than 6 mm long on at least sme flowers; corolla lobes 6-10 mm long. 

    2. Leaves subsessile to shortly petiolate, petioles up to 5 mm long; inflorescences congested to subcapitate, flowers subsessile or on pedicels up to 5 mm long.....Schizocalyx multiflora

    2' Leaves petiolate, petioles 4-20 m long; inflorescences lax, flowers all on pedicels 1-20 mm long, and more than 5 mm long on at least some flowers....Schizocalyx sterculioides

1'. Calyx limb 1-7 mm long, on most flowers less than 6 mm long; corolla lobes 2.5-6 mm long. 

    3. One or more flowers on an inflorescence with a petaloid white calycophyll (this sometimes deciduous after anthess); corolla tube more than 2 times as long as the lobes, the tube 7-8 mm long and the lobes 1.5-3.5 mm long... Schizocalyx bracteosus

    3'. Flowers and inflorescences without calycophylls; corolla tube shorter than, equal to, or up to 2 times as long as the lobes, the tube 1-6 mm long and the lobes 3-9 mm long. 

        4. Calyx limb fully fused and calyptrate in bud, as corolla expands splitting irregularly or sometimes more or less regularly, with lobes or segments 0.6-3.5 mm long. 

            5. Flowers arranged in congested to subcapitate groups, all subsessile to shortly pedicellate, the pedicels up to 1 mm long in flower (but sometimes elongating in fruit); calyx becoming regularly to irregularly lobed...... Schizocalyx peruvianus 

             5'. Flowers arranged in rather lax cymes, each cyme with some flowers sessile to subsessile and some pedicellate, the pedicels up to 15 mm long; calyx becoming irregularly lobed or split. 

                 6. Leaves opposite or more often ternate; pedicels 0.4-5 mm long; Ecuador and Peru....Schizocalyx condoricus 

                 6'. Leaves opposite; pedicels 5-15 mm long; Costa Rica and Panama.... Schizocalyx veraguensis

       4. Calyx limb open or imbricate in bud, truncate or regularly denticulate with teeth up to 0.4 mm long, the calyx limb sometimes tardily elongating and splitting in fruit. 

           7. Corolla lobes 6-9 mm long; plants of southeastern Brazil.... Schizocalyx cuspidatus 

           7'. Corolla lobes 4-5 mm long; plants of western South America. 

               8. Leaves acute to obtuse at base, with petioles 5-20 mm long; stems and leaves hirtellous to pilosulous at least abaxially; corolla tube 2-3 mm long..... Schizocalyx obovatus 

               8'. Leaves broadly obtuse to rounded or truncate at base, with petioles 3-13 mm long; stems and leaves pilose to hirsute; corolla tube ca. 1 mm long...... Schizocalyx truncatus

 
 
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