Dorstenia

  • Authority

    Berg, Cornelius C. 2001. Moreae, Artocarpeae, and (Moraceae): With introductions to the family and and with additions and corrections to Flora Neotropica Monograph 7. Fl. Neotrop. Monogr. 83: 1-346. (Published by NYBG Press)

  • Family

    Moraceae

  • Scientific Name

    Dorstenia

  • Type

    Lectotype, Britton & Wilson, Bot. Porto Rico 5:242. 1924. Dorstenia contrajerva Linnaeus.

  • Synonyms

    Sychinium, Dorstenia contrajerva L., Sychinium ramosum Desv., Dorstenia ramosa (Desv.) Carauta, C.Valente & Sucre, Dorstenia turnerifolia Fisch. & C.A.Mey., Dorstenia brasiliensis Lam.

  • Description

    Genus Description - Plants herbaceous or suffrutescent, monoecious, to l(-2) m tall, unbranched or sparsely branched; stems mainly supraterranean to entirely subterranean; internodes elongate, short, or both short and elongate; uncinate hairs often present. Leaves alternate and in spirals (or almost), often subrosulate; lamina basally attached or peltate, entire or pinnately to palmately or pedately lobed to parted; venation pinnate to subpalmate or (in peltate leaves) almost radiate, brochidodromous to reticulate; margin usually dentate to crenate; stipules subfoliaceous to subulate, plurinervate to uninervate, (subpersistent, mostly firmly coriaceous. Inflorescences bisexual (but in D. cayapia usually unisexual), usually solitary in the leaf axils, pedunculate; receptacle discoid to turbinate to cup-shaped, orbicular, elliptic, quadrangular, (irregularly) stellate, lingulate, or bifurcate, green, (partly) yellow, (partly) purplish, or (partly) reddish-brown, entire to (irregularly) lobed to cren(ul)ate, usually with 1-5 rows of small to minute marginal or submarginal bracts, sometimes on short to rather long marginal or submarginal appendages, or occasionally without bracts and with only filiform (sub)marginal appendages; interfloral bracts lacking or occasionally rudimentary; a (narrow) fringe often present between the flowering face and the edge of the receptacle; flowers connate; hairs often present on the perianths, among the flowers, and on the fringe, minute and globose to club-shaped or to conical, hyaline or purplish. Staminate flowers among the pistillate ones or concentrated in or confined to the periphery of the flowering face, pedicellate (pedicels connate and adnate to the perianth of the sessile pistillate flowers); tepals 2 or 3 (-4), (almost) free; stamens 2 or 3, inflexed in the bud; pistillode occasionally present. Pistillate flowers sessile; perianth tubular, only the upper part free, entire, 2- or 3-lobed; ovary free; stigmas 2, shortly filiform, often unequal in length. Fruit a dehiscent drupelet, exocarp white and turgid-fleshy, at maturity ejecting the crustaceous, mostly tuberculate endocarp body; seed small; testa thin, with a small, slightly thickened, vascularized part below the hilum, endosperm present; embryo small, curved; cotyledons flat and equal in size; radicle relatively long.

  • Discussion

    History

    The genus was established by the description of Dorstenia contrajerva and its variety houstonii from Mexico (Linnaeus 1753). In the 18th century a few tropical American species were added, such as D. drakena by Linnaeus (1759), D. brasiliensis and D. cordifolia by Lamarck (1786), and D. tubicina by Ruiz & Pavon (1798). In the beginning of the 19th century the genus attracted horticultural and botanical interest based on the remarkable features of the inflorescences of material collected in eastern Brazil (e.g., Fischer & Meyer, 1846; Hooker, 1840, 1841). It has been in cultivation in greenhouses, and many species were illustrated in botanical magazines in Europe.

    In the first comprehesive treatment of the genus for the Neotropics by Miquel (1853), 16 species were recognized, the majority South American. For a while interest moved to the Greater Antilles where many species were discovered (Britton, 1908,1924; Grisebach, 1860, 1866; Urban & Ekman, 1929). Rossberg (1934) provided a survey of the species of the Greater Antilles. The interest in the Brazilian species was renewed by studies carried out by Carauta and his collaborators resulting in numerous publications (Carauta, 1972, 1974a, b, 1976; Carauta et al., 1973a,b, 1974a, b, 1975, 1976a,b; Valente & Carauta, 1974, 1975, 1977;Valente et al., 1977), and many new species were described. A study of the taxa in the northwestern part of the Neotropics, as a precursory study for the present revision, was taken up by Berg and van Leeuwen (1982) and was followed by a precursory study of the species of the southeastern part of the Neotropics (Berg, 1985), the latter carried out in collaboration with Carauta (Berg & Carauta, 1985).

    Although the African Dorstenia flora is more speciose than the neotropical one, it was for a long time known only by a species described by Forsskål (1775) as Kosaria foetida, based on material from Yemen. In the end of the 19th and the beginning of the 20th century, numerous new species were described, many of them by Engler between 1894 and 1914.

    Parallel to the study on neotropical representatives of the genus, revisional studies of the Paleotropical species have been carried out by Berg (1978c) and Hijman, resulting in several papers and treatments for African floras (Berg et al. 1977, 1984, 1985; Hijman, 1980, 1989, 1990, 1991). This situation created a unique opportunity to compare the neotropical and Paleotropical Dorstenia floras on the basis of current taxonomic work. This resulted in a proposal for the subdivision of the genus (Berg & Hijman, 1997).

    Morphology

    The genus shows considerable variation in habit and life forms and a diversity in reproductive structures (inflorescences), matched only by a few other angiospermous genera.

    Habit: The genus is a predominantly herbaceous one in a family of woody plants. The woody habit is only found in 11 African species in two sections of the genus. In contrast to the Neotropics, various types of succulence have developed in some of the African sections of the genus.

    All neotropical species are (basically) herbaceous, although a few species, like Dorstenia appendiculata, D. colombiana, and D. turnerifolia, can be suffrutescent, as the rhizomatous and lower part the (leafy) stem can become more or less woody. These species and many others have (rather) slender, erect (to ascending) stems with long internodes and usually rather short rhizomatous parts. They are more or less distinctly phanerophytic. As a rule the leaves have relatively short petioles in these caulescent taxa.

    Another group of species has stems with at least some of the intemodes short. The stems are often for the greater part or entirely subterranean. The leaves are more or less distinctly rosulate and usually have relatively long petioles. Subterranean parts of the stem with short intemodes can be more or less tuberous. These species are hemicryptophytic to geophytic. The two categories of habit forms are not well separated. In Dorstenia ramosa, one of the subspecies has long intemodes, the other subspecies has only short intemodes.

    In the majority of the specimens of D. contrajerva, at least some of the internodes are short, but occasionally all intemodes are long. Young specimens of D. bahiensis are subacaulescent with the leaves rosulate; older specimens have elongate intemodes and the leaves distinctly spaced. Two species with a procumbent habit and long, more or less repent (and more or less rhizomatous) stems, D. flagellifera and D. belizensis, have most or all intemodes long, respectively.

    The suffrutescent habit can be regarded as a primitive state and the shortening of the intemodes as derived, with the possible exception of Dorstenia belizensis and D. flagellifera, in which the long intemodes and the procumbent habit could be regarded as derived. Thus, general trends seem to be from a phanerophytic to a hemicryptophytic to a geophytic life form and from a caulescent to subcanescent to an almost acaulescent habit. In the neotropical Dorstenia species, monocauly is a distinct tendency. Sometimes, e.g., in D. turnerifolia, the (supraterranean parts of the) stems are branched.

    Most species occur in humid and shaded places in forest undergrowth. Only a few subcaulescent to acaulescent and geophytic species, Dorstenia brasiliensis and D. cayapia, have (partly) "escaped" from this habitat to more open and dry vegetation, such as savanna and cerrado; both can behave as weeds.

    The neotropical Dorstenia flora differs from the Old World one in lacking truly woody frutescent to almost arborescent forms, in lacking forms with distinctly and often much-branched stems, and in lacking distinct succulence in supraterranean or subterranean stem parts, a feature connected with occurrence in dry habitats (cf. Engler, 1898; Berg, 1977b, 1978c; Berg & Hijman, 1977, 1999; Hijman, 1989).

    Leaf: The genus shows considerable variation in the leaves. The caulescent species usually have elliptic to oblong leaves, mostly with short petioles. The lamina is entire, often lobed to parted only in Dorstenia choconiana. The other caulescent species with lobed to parted leaves, D. ramosa and D. grazielae, have relatively long petioles and are related to a group of subcaulescent species with long petioles and often incised laminas. In the group of subcaulescent to (sub)acaulescent species, one can roughly recognize two groups. One group, including, e.g., D. contrajerva and/), arifolia, has relatively large leaves, these being often lobed to parted. The other group, including, e.g.) D. brasiliensis and the group of Antillean species, have relatively small and entire leaves, with the exception of D. cayapia p.p., in which the lamina may be palmately lobed to parted.

    In the group of caulescent and in the group of largeleaved, subcaulescent species, the venation is usually more or less distinctly brochidodromous, thus with loop-connected lateral veins. In the subcaulescent to acaulescent, small-leaved species, the venation passes into the craspedodromous type (with lateral veins, often after branching terminating at the margin). In laminas with brochidodromous venation, part of the tertiary venation can be scalariform (with many or some of tertiary veins running parallel, perpendicular to the lateral veins). In the group of Antillean species, peltate leaves are common. Basally attached and peltate leaves can occur in the same species. In distinctly peltate leaves, the venation passes from pinnate into (almost) radiate. The venation is mostly pinnate, but subpalmate in some of the specimens of D. cayapia and D. contrajerva. The margin of the lamina is usually crenate to dentate.

    The stipules are coriaceous and persistent in all species. In Dorstenia elata, the stipules are mostly distinctly foliaceous and plurinervate. Large stipules, either indistinctly plurinervate or uninervate, are found in several species, e.g., D. urceolata and D. arifolia. In the majority of the species, the stipules are small, mostly triangular or subulate, and uninervate. In some of the caulescent species, the small stipules can become patent to deflexed.

    The (subacaulescent form with long-petiolate leaves and forms with lobed to parted laminas are rarer in the Old World Dorstenia flora, represented by, e.g., D. barnimiana Schweinfurth and D. letestui Pellegrin. Broad stipules are found only in woody species and in one of the herbaceous species, D. picta Bureau (cf. Berg, 1978c; Berg & Hijman, 1977).

    Inflorescence: The inflorescences are usually solitary and borne in the axils of the leaves, in some species on more or less distinct short-shoots with reduced stipules.

    The receptacle varies in shape; it can be orbicular, elliptic, obovate, more or less distinctly (quadrangular, stellate, or furcate. The most extreme shape of receptacle, the furcate one of Dorstenia ramosa, can be regarded as derived from the quadrangular one, such as in D. contrajerva (Fig. 33C).

    The receptacle is centrally to eccentrically attached to the peduncle. Its margin can be entire, dentate, crenate, more or less deeply lobed, or appendiculate. The receptacle and/or the structure of the margin of the receptacle is often shaped according to the position and the size of the bracts; e.g, the larger bracts are found on the comers of quadrangular receptacles or on the lobes of stellate receptacles.

    In almost all neotropical species, the receptacle bears small bracts, mostly arranged in several rows. They are found on the margin, (just) below the margin, and on the fringe (the narrow area between the edge of the receptacle and the flower-bearing part of the flowering surface of the receptacle; see Fig. 33D). The bracts differ in dimensions and shape. Especially in inflorescences with a single row of bracts, the larger and the smaller bracts are alternating. The bracts are mostly appressed, but in several species, especially the marginal bracts are patent and radiating, which often accentuates the stellate shape of the receptacle. The bracts on the fringe are often minute.

    In some species, teeth and appendages may arise on or just below the margin, at places where the bracts, especially the larger bracts, are situated. In Dorstenia appendiculata, the larger bracts are born by semiorbicular to linear, to 1.2 cm long appendages, which arise below or also at the margin. In D. grazielae, the marginal bracts (or also those below the margin) are sometimes bom on to 2.5 cm long filiform appendages. Filiform appendages on (or below) the margin are found in all specimens of D. ramosa. As in many Paleotropical species, bracts are usually not formed in D. ramosa, and, thus, the margin of the receptacle is rather appendiculate than bracteate (see Fig. 33B). Interfloral bracts are only found in the (primitive) West African species, D. djettii Guillaumet(cf. Berg, 1978c); they are peltate and the upper part caducous (see Fig. 33 A). However, vestigal interfloral bracts sometimes occur in D. turnerifolia from Brazil. The flowering (sur)face of the receptacle may be turned downwards, sideways, or it can change from downwards to sideways or from sideways to upwards in the course of the development of the inflorescence or during anthesis.

    The neotropical Dorstenia species show much less variation in the shape of the receptacle than the Paleotropical ones, partly due to the fact that the majority of the Paleotropical species have receptacles with well-developed (sub)marginal appendages and lack bracts. Moreover, the fringe of the receptacle can be very broad in African species (see Fig. 33D). The inflorescences are always bisexual, except in D. cayapia. The small staminate and pistillate flowers are intermingled, although the pistillate ones are often more or less concentrated in the central part of the flowering face. In a few species (e.g., D. turnerifolia), the staminate flowers are (almost) confined to the peripheral part of the flowering face. Anthesis of the pistillate flowers mostly preceeds that of the staminate ones in the same inflorescence. D. cayapia is the only species of the genus in which unisexual inflorescences are usual. The staminate inflorescences appear first on the plant, and when they have withered the pistillate ones appear (Hoen, unpubl, thesis Utrecht). However, bisexual inflorescences sometimes occur, but they show clear differences in the proportions of staminate and pistillate flowers.

    Just as in. the inflorescence of the related African genus Scyphosyce (cf. Berg, 1977a), the pistillate flowers are sessile and the staminate ones pedicellate. In the saucer-shaped to cup-shaped receptacle, the perianths of the pistillate flowers are connate and/or adnate to the (fused) pedicels of the staminate flowers (and in some cases also with the stalks of interfloral bracts), thus forming a layer of tissue with cavities, containing the (free) pistils (see Fig. 33 A).

    The inflorescence or parts of the inflorescence are green, yellowish, red-brown, or purplish (to blackish). In some species, the peduncle and all parts of the receptacle are colored, in other species only the peduncle, only the margin, or only the flowering face. Sometimes only the stigmas are (purplish) colored. The colors and the parts that are colored often vary within the species.

    Flowers: The flowers are rather uniform in the genus. The perianth of the pistillate flower is tubular and the apex is sometimes minutely 3-lobed (e.g., in Dorstenia turnerifolia). The pistil is free. The stigmas are small, filiform, and equal or unequal in length.

    The staminate flowers of neotropical species have sometimes three, mostly two, small, almost free tepals and three or two, small stamens, respectively. The stamens are small. The filament is often swollen at the base and inflexed before anthesis, becoming gradually straight at anthesis, and often elongating. A minute pistillode can sometimes be found.

    The minute hairs on the perianths and also those among the flowers are often globose to clavate. They are hyaline and purplish or red-brown and may cause glistening of (parts of) the flowering face.

    Features of the ovules vary. In some of the species, the nucellus is surrounded by two integuments; in others, the side of the cover of the nucellus towards the funicle consists of more or less swollen tissue instead of two distinct integument layers. The embryo sac shows differences in the number of synergids, antipodes, and polar nuclei.

    In African species, both types of integuments also occur; polar nuclei can be two or four; synergids can be occasionally absent, and the number of antipodes varies from 0 to 25.

    Pollen: A study by Hoen and Punt (1989) on pollen of Dorstenia and other genera of the tribe Dorstenieae reveals a considerable differentiation. Nine types of Dorstenia pollen could be recognized, some rare ones and some more common. On the basis of 18 trends in differentiation, the pollen types could be be arranged in two groups. The classification of pollen matches only partly the grouping of species as proposed here.

    Fruit: The fruit of Dorstenia is a dehiscent drupe(let), stipitate and with a white exocarp. The fruit is initially enclosed, but by enlargement of the fruit and elongation of the stipe it breaks through the upper surface (= flowering face) of the receptacle. The upper part of the turgid-fleshy exocarp splits and keeps the crustaceous endocarp body between the two halves, which can be released when the vascular bundle connecting the tops of two halves over the top of the endocarp body breaks. In the small fruits, as found in all neotropical Dorstenia species, the endocarp body is usually tuberculate and is ejected. The tuberculate surface of the endocarp body is related to the ejecting mechanism (cf. Overbeck, 1924; Schleuss, 1958). In the macrospermous woody African species, the endocarp body is smooth and is simply squeezed out. In a few neotropical species, the surface of the endocarp is (almost) smooth, as in D. cayapia with its relatively large endocarp bodies. The small fruit contains a seed with a thin testa, with a slightly thickened and with a (poorly) vascularized part below the small hilum. Endosperm is present and the embryo has small, flat, and equal cotyledons and a relatively long radicle.

    In the macrospermous African species, the seeds do not contain endosperm and the embryo is large, with thick and often unequal cotyledons and a small radicle. In the West African epiphytic species D. astyanactis Ake Assi, the drupe is indehiscent and is expelled by elongation of the stipitate base of the fruit (cf. de Granville, 1971).

    Cytology

    The chromosome numbers range from 2n = 24 to 2n = 72 (Krause, 1931;LeCoq, 1963,1964; Federov, 1969; Hoen, unpubl, thesis 1983), with x = 12 and 13 as basic numbers for African species and x = 14, 15, and 16 for American species, and include diploids, triploids, tetraploids, pentaploids, hexaploids, and aneuploids, as listed below. The most common basic numbers in the family are x = 13 and 14 (cf. Federov, 1969).

    Reproduction: Pollination and Dispersal

    Nothing is known about the pollination of Dorstenia. Several features, such as shape of the inflorescence, appendages, colors, glistening surfaces caused by the characteristic hairs on the perianths and often elsewhere on the upper surface of the receptacle, and, in several cases, fragrance, can be associated with myophily; there are no records confirming it. Visits of beetles have been observed in some species in Cameroun and Gabon (pers, comm. Hijman). One may wonder whether the differentiation and variation in the inflorescence has any adaptive significance at all (cf. Berg 1977a).

    As the staminate and pistillate flowers occur mixed and crowded, so that stigmas can get in touch with pollen, one may assume that geitonogamous self-pollination will often happen. There is a tendency for anthesis of pistillate flowers to preceed that of staminate flowers. In several species, there is a distinct time lapse between anthesis of pistillate and staminate flowers, but in others, there is no or minimal lapse.

    Several species kept in greenhouses produce seeds profusely, others not. This difference cannot be explained by differences in position of the flowers and possibilities for “autogamous” pollination. However, some species produce seeds even after the stigmas have been removed (Hoen, unpubl, thesis), and the pistillate inflorescences of (the functionally dioecious) Dorstenia cayapia produce seeds without the presence of pollen vectors. These data suggest the occurrence of some type of agamospermy. Both autogamy and agamospermy could explain variation patterns, as a high degree of local morphological uniformity and striking differences between populations, even over short distances. De Granville (1971) has observed normal fertilization in D. contrajerva and D. embergeri G. Mangenot, but did not find seed production after removal of the stigmas, and suggested that pollination is needed for reproduction. Hoen (unpubl, thesis, 1983) found that differences in greenhouse conditions, probably largely light levels, did influence (“spontaneous”) seed production.

    Vegetative reproduction, which occurs in some (semi)succulent African species (by arrested branchlets that may become small tubers and get detached) is not found in the neotropical species.

    Autochory appears to be a common phenomenon in Dorstenia species. As the species often grow along stream(let)s, further transport of ejected endocarp bodies may occur by running water. The genus does not have obvious means of long-distance-dispersal. Moreover, the seeds appear to be viable for only a short time. The Sudanian annual species, D. annua Friis & Vollesen (1982), is presumedly exceptional with regard to the longevity of the seeds, normally viable for a short time.

    Conservation

    Small or very small ranges of distribution, some species being known only from a single locality (as Dorstenia belizensis and D. conceptionis), and rather strict ecological requirements, mostly suitable places in primary forest, mean that a good number of Dorstenia species are seriously threatened by extinction (cf. Carauta & de Castro, 1982). One of these species, D. brevipetiolata, may be extinct already.

    Subdivision of the Genus

    The first subdivision of the genus was proposed by Sprengel (1826). At that time, the species known were neotropical, except for Dorstenia radiata (Forssk&l) Lamarck (= Kosaria radiata Forssk&l) from Yemen. Sprengel’s subdivision was based on the growth habit:

    1. Scapigerae, comprising the neotropical species;

    and

    2. Caulescens, with Dorstenia radiata.

    Endlicher’s subdivision (1842) was based on the shape of the inflorescence:

    1. Dorstenia, comprising all species except for one; and

    2. Sychinium, with only Dorstenia ramosa (= Sychinium ramosum Desvaux, 1826), a species with a furcate receptacle. Fischer and Meyer (1846) designed a subdivision based on the growth habit and characters (mainly the shape) of the receptacle:

    1. Sychinium, with only Dorstenia ceratosanthes

    (= D. ramosa);

    2. Lecanium, comprising the caulescent neotropical species;

    3. Dorstenia, comprising the subacaulescent neo-

    tropical species; and

    4. Kosaria, comprising the caulescent and acaules-

    cent Paleotropical species, all with a radiate

    receptacle.

    This subdivision was adopted by Walpers (1848-1849) and, recently, largely so by Carauta (1976, 1978a).

    Carauta recognized sect. Lecania and sect. Sychinia, and divided Fischer & Meyer’s "section" Dorstenia into sect. Dorstenia (with D. contrajerva and several related species) and sect. Emygdioa (with D. brasiliensis and several related species). Carauta’s subdivision was based on the growth habit and life form and on characters of the inflorescence and the leaf.

    It is surprising that Miquel (1853) neglected the previous subdivisions based on characters of the inflorescence by combining species with a furcate receptacle (Dorstenia ramosa and D. ceratosanthes) and species with an orbicular to elliptic receptacle (D. arifolia) into a single species D. multiformis. In the treatment of Dorstenia for Flora Brasiliensis (1853), Miquel grouped species according to the growth habit in three groups:

    1. frutescent to suffrutescent plants with stems with

    long intemodes;

    2. suffrutescent plants with stems with short

    intemodes; and

    3. subacaulescent plants.

    In 1863 Lemaire proposed to subdivide Dorstenia into:

    1. Furcatae, comprising the species with a furcate

    receptacle;

    2. Quadratae, comprising the neotropical species

    with quadrangular to orbicular receptacle; and

    3. Radiatae, comprising the Paleotropical species

    with a radiate receptacle.

    When Bureau made his important revision of Dorstenia (1873), the rich Dorstenia flora of Africa became better known. Bureau, however, did not propose a formal subdivision, but only grouped the species based on key characters. After separating the New World and Old World species, he keyed out groups of species, based on: stems caulescent or acaulescent; base of the stem (for the caulescent Old World taxa) rhizomatous, tubiferous, or tuberous; inflorescences orbicular or elliptical to (!) furcate; laminas peltate or basally attached; and stipules foliaceous and plurinervate or triangular and pungent to subulate.

    In a treatment of the African representatives of the genus, Engler (1898) subdivided Dorstenia into three (African) sections: (1) Nothodorstenia, (2) Eudorstenia, and (3) Kosaria. This subdivision was based on the presence and arrangement of bracts on the receptacle, the number of stigmata, and partly on characters of the stem and growth habit.

    It is clear that the subdivisions proposed were mainly based on the growth habit (and the life form) and characters of the inflorescence. The weakness of the basis for the subdivisions is clear, as they lack consistency in the use of characters and are largely based on material from only one of the major areas of distribution.

    A classification of Dorstenia, based on floristic and revisional studies for both the New and Old World, is proposed by Berg and Hijman (1999). In the whole genus, nine sections can be recognized:

    1. section Nothodorstenia Engler, with five woody

    species in Africa (mainly West Africa);

    2. section Xylodorstenia Hijman, with six woody

    species in Africa (most of them in West Africa);

    3. section Lecanium, with 22 non-succulent

    caulescent herbaceous species, 20 in the Neotropics, and two in (West) Africa;

    4. section Lomatophora Hijman, with 26 non-

    succulent caulescent herbaceous species in Africa (most of them in West and Central Africa);

    5. section Dorstenia, with eight non-succulent,

    partly acaulescent herbaceous species in the Neotropics;

    6. section Kosaria (Forsskål) Fischer & Meyer,

    with 16 (semi)succulent caulescent species, including an annual one and an epiphytic one, in Africa (mainly East Africa), with extensions to Madagascar, Yemen, Saudi Arabia, Socotra, Sri Lanka, and India;

    7. section Bazzemia Hijman, with one non-succulent

    acaulescent species in Africa (Mozambique);

    8. section Emygdioa, 18 non-succulent, partly

    acaulescent species in the Neotropics; and

    9. section Acauloma Hijman, three succulent

    acaulescent tubiferous species in East Africa and Socotra.

    In most cases, the delimitations of these infrageneric subdivisions are not very clear-cut. Six sections are entirely Paleotropical and include two sections of woody to suffrutescent taxa, two sections with succulent or semisucculent taxa, and two with herbaceous non-succulent taxa. One of these, the monotypic section Bazzemia, resembles in habit members of the neotropical section Emygdioa. Two African species belong to the largely neotropical section Lecanium.

    The three neotropical sections cannot be sharply delimited because of the lack of very clear discontinuities in morphological (and ecological) variation.

    1. Section Lecanium comprises distinctly caulescent (suffrutescent to herbaceous) species, with spaced, mostly shortly petiolate leaves. All members of this group are components of the undergrowth of rain forest. The species of this group occur in eastern Brazil, the Andes region, and Central America. The group comprises species like Dorstenia appendiculata and D. turnerifolia, which can be regarded as the most primitive ones among the neotropical species, due to the suffrutescent stem, the presence of three stamens, and the occasional occurrence of interfloral bracts.

    This section also comprises the species which show distinct relations with African species: Dorstenia appendiculata shows similarities to the frutescent African species, D. dorsteniodes (Engler) Hijman & C. C. Berg; D. turnerifolia shows similarities to African D. subdentata Hijman & C. C. Berg; and D. urceolata resembles African D. picta. Thus, the transatlantic affinities are closest between eastern Brazilian species and species occuring in Cameroun and Gabon.

    Within section Lecanium one can recognize a group of species with small, triangular to subulate, uninervate stipules and a group of species with relatively large, (broadly to narrowly) ovate (in Dorstenia elata almost foliaceous) stipules, often with (distinct to faint) plurinervate venation. The group with small stipules comprises the caulescent species of Central America and the Andean region (the species numbered 10 to 17) and several of the eastern Brazilian species (the species numbered 1 to 9); they mostly have hirsute to hirtellous indumentum on the upper leaf surface. The group with large stipules comprises the eastern Brazilian species, D. elata, D. hildegardis, and D. urceolata. This group show distinct relations with the (partly) sub-caulescent species included in section Dorstenia.

    2. Section Dorstenia comprises subcaulescent (to caulescent) species with large, often lobed to parted leaves with long petioles. Some species pairs of this group show remarkable similarities and parallel variation. When sterile, Dorstenia arifolia can hardly be separated from D. ramosa ssp. ramosa, nor D. contrajerva from D. drakena. Dorstenia arifolia and D. drakena have inflorescences with an elliptic receptacle. In D. contrajerva, the receptacle is basically quadrangular; the furcate receptacle of D. ramosa can be regarded as derived from a quadrangular one. Especially depauperate specimens of D. drakena and D. contrajerva show similarities to representatives of the following section. The group does not show resemblances to any of the African species.

    3. Section Emygdioa comprises species with relatively small leaves and long petioles and stems with mostly all or many intemodes short. Dorstenia belizensis and D. flagellifera are exceptional because of the presence of only long intemodes. Several species of this section have a geophytic life form and are adapted to more or less dry and open vegetation (D. brasiliensis and D. cayapia p.p.). Within this third section, the 13 species of the Greater Antilles (including D. belizensis from Belize) constitute a more or less distinct group of species, being closely related, partly in a rather complex way. Except for their habitat preference, they are characterized by often having very small leaves and by peltate laminas. One of the members of this group, D. fawcettii, shows remarkable similarities to D. tenuis, occuring in the southernmost part of geographic range of the genus. The Mexican D. excentrica shows close resemblances to D. brasiliensis. In section Emygdioa, the rare D. conceptions is morphologically rather isolated. This section does not show distinct relations with the African Dorstenia flora. However, one of the African species, D. zambesiaca Hijman (from Moçambique) is in habit similar to the prevalent one in section Emygdioa.

    Systematics

    The present study is almost entirely based on morphological characters, a rather unsatisfactory approach, as it leaves many taxonomic problems (related to the peculiar variation patterns) unsolved. The still scarce data about the variation in chromosome numbers and the (probable) occurrence of agamospermy points to the necessity of biosystematic studies, which may solve, at least partly, the problems and the questions indicated by the present study, in particular those regarding Dorstenia drakena. In Africa, many more complex situations exist (cf. Berg & Hijman, 1999).

    Local Names and Use

    In Mexico and Central America, the common vernacular name for Dorstenia contrajerva and/), drakena is contra hierba or contrahierba (or variants contra yerba or contrayerba). In these regions, this name is (sometimes?) used also for other Dorstenia species, such as D. lindeniana. Dorstenia drakena is also known by the names barbodillo or barboria in Jalisco and Sonora, Mexico, respectively. In Panama (San Blas), D. contrajerva is known by the Kuna name nanduli and in Puerto Ricoa as tusilla.

    In Brazil the most common name for all species, but in particular for the acaulescent or geophytic species (e.g., Dorstenia brasiliensis and D. cayapia), is caiapiá or variants such as caapiá, capiá, Carapá, carapiá, caripá, carpales, caxapiá; some variant is also used in adjacent countries (Argentina and Paraguay). Other vernacular names used in Brazil are apii, chupa-chupa, contra-erva, figueira terrestre,figueirilha,figueirilho, liga-liga, liga osso, taropé, teiú (or teiú-açu), and tiú (or tiú-açu).

    The subterranean parts of the plant are used to prepare concoctions applied for many medicinal purposes, e.g., against snake bites (cf. Peckolt & Peckolt, 1890).

    Distribution and Ecology: The distribution of the neotropical Dorstenia flora shows some pecularities. The Neotropics can be divided into two (almost exclusive) domains, of which the boundaries are defined by the distributions of D. brasiliensis and D. contrajerva (see maps, Fig. 80.6 & 81.8). The areas of these two species hardly overlap. The southeastern domain has its center in eastern Brazil, the northwestern domain has its center in northern Central America and the Greater Antilles.

  • Common Names

    contra hierba, contrahierba, contra yerba, contrayerba, nanduli, tusilla, caiapiá, caapiá, capiá, Carapa, carapiá, caripá, carpales, caxapiá, apii, chupa-chupa, contra-erva, figueira terrestre, figueirilha, figueirilho, liga-liga, liga osso, taropé, teiú (or teiú-açu), tiú (or tiú-açu)

  • Distribution

    Brazil South America|