Chamaecrista (L.) Moench, Methodus: 272. 1794.
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https://dx.doi.org/10.3897/phytokeys.240.101716 |
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https://treatment.plazi.org/id/54DCAE51-3CA1-0177-BD63-6BD990EC34E9 |
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scientific name |
Chamaecrista (L.) Moench, Methodus: 272. 1794. |
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Chamaecrista (L.) Moench, Methodus: 272. 1794. View in CoL
Figs 22 View Figure 22 , 28 View Figure 28 , 29 View Figure 29
Cassia [infragen. unranked] Chamaecrista L., Sp. Pl. 1: 379. 1753. Type: Cassia chamaecrista L., nom. utique rejic. [≡ Cassia fasciculata Michx. (≡ Chamaecrista fasciculata (Michx.) Greene)]
Cassia sect. Chamaecrista (L.) DC., Hist. Nat. Méd. Casses 24, 118.1816. Lectotype (designated by Britton and Rose 1930): Cassia nictitans L. [≡ Chamaecrista nictitans (L.) Moench]
Sooja Siebold, Verh. Batav. Genootsch. Kunst. 12: 56. 1830. Type: Sooja nomame Siebold, nom. inval. (nom. nud.) [≡ Cassia mimosoides var. nomame Makino (≡ Chamaecrista nomame (Makino) H. Ohashi)]
Disterepta Raf., Sylva Tellur.: 126. 1838. Type: Disterepta pilosa (L.) Raf. [≡ Cassia pilosa L. (≡ Chamaecrista pilosa (L.) Greene)]
Hepteireca Raf., Sylva Tellur.: 126. 1838. Type: Hepteireca glandulosa (L.) Raf. [≡ Cassia glandulosa L. (≡ Chamaecrista glandulosa (L.) Greene)]
Dialanthera Raf., Sylva Tellur.: 127. 1838. Type: Dialanthera glandulosa (L.) Raf. [≡ Cassia glandulosa L. (≡ Chamaecrista glandulosa (L.) Greene)]
Xamacrista Raf., Sylva Tellur.: 127. 1838. Type: Xamacrista trifolia Raf. [= Cassia chamaecrista L. (≡ Chamaecrista fasciculata (Michx.) Greene)]
Nictitella Raf., Sylva Tellur.: 128. 1838. Lectotype (designated by Irwin & Barneby, 1982): Nictitella amena Raf. [= Cassia nictitans L. (≡ Chamaecrista nictitans (L.) Moench)]
Ophiocaulon Raf., Sylva Tellur.: 129. 1838. Lectotype (designated by Irwin & Barneby, 1982): Ophiocaulon serpens (L.) Raf. [≡ Cassia serpens L. (≡ Chamaecrista serpens (L.) Greene)]
Cassia subg. Lasiorhegma Vogel ex Benth., Fl. Bras. 15(2): 129. 1870. Type not designated.
Type.
Chamaecrista nictitans (L.) Moench [≡ Cassia nictitans L.]
Description.
Trees, treelets, shrubs and subshrubs, lacking spines or prickles. Stipules diverse in shape and size, persistent or caducous. Leaves distichous or spiral, bifoliolate or paripinnate; extrafloral nectaries when present on petiole, generally on the rachis between the pairs of leaflets or in the axis of the inflorescence, sessile or stipitate, the secretory surface concave, rarely convex; leaflets 1-65 pairs. Inflorescence a fascicle, raceme or panicle; bract 1, caducous or persistent, bracteoles 2, alternate, located at mid-length or slightly above the pedicels, persistent. Flowers hypogynous, asymmetrical, hypanthium absent; sepals 5, free; petals 5, free, yellow, or yellow with red base, sometimes red, orange or pink; stamens 5-10, homomorphic, filaments glabrous, anthers dehiscent by apical pores, pubescent laterally, rarely with the indumentum covering the entire anther; pollen subprolate to prolate, syncopate, fused at the poles; ovary stipitate. Fruit a compressed legume, valves papyraceous or coriaceous, elastically dehiscent through both margins, becoming twisted after dehiscence. Seeds variable in shape and colour.
Chromosome number.
Haploid numbers n = 7, 8, 14, 16, 24 ( Goldblatt and Johnson 1979 -; Souza 2004).
Included species and geographic distribution.
368 species, pantropical with a few species reaching temperate areas (Fig. 28 View Figure 28 ).
Ecology.
Chamaecrista species typically occur in open environments. Although several species are widespread, such as C. rotundifolia (Pers.) Greene, C. mimosoides (L.) Greene and C. flexuosa (L.) Greene, a high diversity is concentrated in Brazilian savannas and in the "campos rupestres’’ vegetation ( Irwin and Barneby 1978, 1982; Rando et al. 2020b). In these centers of diversity, several species have evolved underground systems that allow survival after fire and during long dry periods ( Rando et al. 2016). One clade of arborescent Chamaecrista species is mostly restricted in the Amazon and Atlantic tropical rainforests.
Human uses.
Some species are used in traditional African medicine. For example, C. absus (L.) H.S. Irwin & Barneby is used as a purgative, for treating wounds and sores, and also against syphilis ( Lewis 2005a). In China and Japan, C. mimosoides is used as a tea, and in Tanzania, against snake bites and scorpion stings ( Lewis 2005a). In Brazil, dried leaflets and branches of some species [ C. choriophylla (Vogel) H.S. Irwin & Barneby, C. cotinifolia (G.Don) H.S. Irwin & Barneby, C. orbiculata (Benth.) H.S. Irwin & Barneby and C. rotundata (Vogel) H.S. Irwin & Barneby] are used as decorative objects ( Cota et al. 2020).
Etymology.
A composite name from the Greek Chamae (= small, of little growth), and the Latin crista, referring to the crest ( Rizzini and Rizzini 1983; Radcliffe-Smith 1998). The name was applied in reference to the very short filaments of stamens forming a crest ( Greene 1905).
Notes.
The largest genus of the tribe can be easily recognised by a set of features: the presence of two bracteoles on the pedicels, stamens generally homomorphic, poricidal anthers (Fig. 22 View Figure 22 ) and elastically dehiscent fruits. Since the segregation of Chamaecrista from Cassia , the infrageneric classification of the genus remains the subject of intensive studies, changing the rank, expanding, restricting, or combining the names within the genus (e.g., Bentham 1871; Irwin 1964; Irwin and Rogers 1967; Irwin and Barneby 1976a, 1976b, 1977, 1978, 1982; Rando et al. 2016; Souza et al. 2021). In short, three highly supported clades with strong correlation in habit and habitat variation are currently well established in Chamaecrista : (i) a clade of arborescent species, with ramiflorous inflorescences and extrafloral nectaries; (ii) a clade of shrubs, with axillary and reduced racemes, distichous phyllotaxy, and with extrafloral nectaries; and (iii) the most diverse clade, embracing shrubs with terminal racemes or panicles, spiral phyllotaxy, without extrafloral nectaries, and commonly with glandular trichomes on branches, leaves and inflorescences ( Conceição et al. 2009; Souza et al. 2021). Within these groups there are also some highly supported clades, consistent with morphology, and the trend has been to improve their circumscription to arrive at a stable and practical infrageneric classification. However, more molecular phylogenetic studies are needed to clarify relationships in the most diverse clades (ca. 200 species in savannas and rocky fields), in which recent diversification (ca. 5 Ma; Rando et al. 2016; Vasconcelos et al. 2020) complicates the understanding of relationships among species.
Taxonomic references.
Bentham (1871); Buril et al. (2011); Cota et al. (2020); Irwin (1964); Irwin and Barneby (1976a, 1976b, 1977, 1978, 1981, 1982); Irwin and Rogers (1967); Rando et al. (2016, 2020b); Souza et al. (2021).
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