Trithrinax Martius (1837: 149)

Cano, Ángela, Perret, Mathieu & Stauffer, Fred W., 2013, A revision of the genus Trithrinax (Cryosophileae, Coryphoideae, Arecaceae), Phytotaxa 136 (1), pp. 1-53 : 16-24

Trithrinax Martius (1837: 149) . Type:— Trithrinax brasiliensis Mart.

Diodosperma Wendland (1878: 36) . Type:— Diodosperma burity H. Wendl. (Incertae Sedis)

Chamaethrinax H. Wendl. ex Pfister (1892: 46 , treated as Chamathrinax ). Type:— Chamaethrinax hookeriana H. Wendl. ex Pfister (Incertae Sedis) .

Palms solitary to clustered, pleonanthic, hermaphroditic. Stem greyish, frequently covered with spiny leaf sheaths, leaf scars prominent; aerial roots forming a basal cone, the roots rather smooth to rugose, light brown or greyish. Leaves palmate; leaf sheath tubular, smooth at the base, reticulate with spiny margins towards the apex, leaf sheath spines woody, square to rectangular in cross section; petiole flat to convex adaxially and convex abaxially, smooth, light yellow-green or green, occasionally bearing a whitish indumentum; hastula prominent, acute adaxially and inconspicuous, fragile and caducous abaxially; leaf blade coriaceous, lax to rigid, loosely covered with a white-waxy indumentum, regularly segmented or biflabellate; leaf segments pendant to erect, with a bifid, acute, sometimes lignified and spiny apex, plication induplicate. Inflorescences interfoliar, branched into two (rarely three) orders, shorter than the leaves, erect at anthesis, pendant when fruiting; peduncle dorsi-ventrally compressed in cross section, covered with a light brown-waxy indumentum, frequently tightly enveloped by numerous layers of the persistent spiny leaf sheaths; prophyll covered with a white-waxy indumentum towards the apex, coriaceous, reddish, opening laterally; peduncular bracts opening laterally or bilaterally, slightly keeled, reddish, coriaceous, smooth towards the base and covered with a whitewaxy indumentum towards the acute apex; rachis similar to the peduncle at its basal portion, medial and apical portions terete in cross section, smooth, the apical portion bearing several spirally arranged rachillae and ending in a fertile rachilla; rachis-bracts subtending individual branches, basal rachis bracts similar to the peduncular bracts, medial and apical rachis bracts smaller, weakly keeled, opening laterally, reddish, fragile, smooth or with a white-waxy indumentum, their apices disintegrating late in the development of the inflorescence; branches smooth, yellow (at flowering) or pale green (at fruiting), dorsi-ventrally compressed and slightly channelled to terete in cross section, alternating or spirally inserted in the rachis; branches ending in a fertile rachilla; rachillae whorled to spirally arranged, terete in cross section, smooth, pale yellow at anthesis becoming green at fruiting stage, subtended by individual bracts, the latter small, inconspicuous, deltoid, falling off at fruiting stage, occasionally one or two basal rachillae of the basal branches exhibiting additional branching. Flowers apparently sessile, spirally arranged on the rachilla, pale yellow at full anthesis, fragrant, each flower subtended by a small, inconspicuous, deltoid floral bract, which falls off at fruiting stage; sepals 3, ovate, slightly keeled, acute, basally connate, margins entire; petals 3, ovate, slightly keeled, imbricate, free, margins entire; stamens 6, free, basally adnate to the inner side of the petals; filaments longer than the perianth and the gynoecium, clearly wider towards the base, much thinner towards the apex; anthers dorsifixed, versatile; dehiscence latrorse; gynoecium 3-carpellate, apocarpous, ovary obovate to oblong, style erect or curved, stigmatic branch papillose on its ventral side. Fruits one-seeded, globose, with an apical stigmatic remain, epicarp smooth, thin, mesocarp fleshy, endocarp thin; seed globose, hilum circular, basal with ascending branches, endosperm homogeneous, the seed detaching from the endocarp at mature stage of the fruit. Eophyll simple, lanceolate.

Etymology: — Tri: three; thrinax : generic name Thrinax Swartz (1788: 4) . Martius (1837) identified in the new genus a 3-carpellate gynoecium, which differed from the gynoecium of the genus Thrinax characterized by its single carpel.

Distribution: —Three species, distributed in subtropical South America, in southeastern Bolivia, northern and central Argentina, western Paraguay, southern Brazil and western Uruguay ( Fig. 5 ).

Taxonomic notes: — Diodosperma was described by Hermann Wendland in 1878, based on seeds from central-southern Brazil. The same year Drude compared Wendland’s description with the seeds of Trithrinax and found them very similar. However, it is only in 1882 that he formally placed Diodosperma as a synonym of Trithrinax , a taxonomic decision that was also adopted by Beccari (1907) and by Dransfield et al. (2008).

Govaerts & Dransfield (2005) and Dransfield et al. (2008) considered Chamaethrinax as an invalid name and cited page 19 of Pfister’s publication. However, we consider that the name is valid because the genus is correctly described on page 46, with further characters included in the key to the genera.

Key to the Species of Trithrinax

1. Peduncular bracts fibrous-reticulate ( Fig. 17-E ) ....................................................................... Trithrinax schizophylla .

- Peduncular bracts not fibrous-reticulate ...................................................................................................................... 2.

2. Leaf blade light to dark green; filaments as long as the anthers ( Fig. 7 ). Brazil and Paraguay..................................... .................................................................................................................................................. Trithrinax brasiliensis .

- Leaf blade pale green to greyish; filaments 2-3 times longer than the anthers ( Fig. 12 ). Argentina and Uruguay........ ................................................................................................................................................... Trithrinax campestris .

Multi-access key to the species of Trithrinax

Numbers refer to the numerical list of taxa (Appendix 1). Numbers in parenthesis indicate that the character is only rarely found in that taxon.

Habitat

1. Geography: Country

a. Argentina (A)

2, 3a, 3b

b. Bolivia (Bo)

3a

c. Brazil (Br)

1a, 1b, (3b)

d. Paraguay (P)

1b, 3b

e. Uruguay (U)

2

2. Geography: Departments, Provinces or States

a. Chaco, Formosa (A), Mato Grosso do Sul (Br), Boquerón, Concepción, Presidente Hayes (P)

3b

b. Chaco, Córdoba, Corrientes, Entre Ríos, San Luis, Santa Fe, Santiago del Estero, Tucumán ( A) , Colonia, Paysandú, Río Negro, San José, Soriano ( U) .

2

c. Jujuy, Salta ( A) , Chuquisaca, Santa Cruz, Tarija (Bo)

3a

d. Rio Grande do Sul (Br)

1a, 1b

e. Santa Catarina, Paraná (Br), Alto Paraná ( P)

1b

Vegetative characters

3. Habit

a. Solitary

1a, 1b

b. Clustering

(1a), (1b), 2, 3a, 3b

4. Marcescent leaves

a. Reaching the ground (covering the stem as a skirt)

2, (3a)

b. Not reaching the ground

1a, 1b, 3a, 3b

5. Stem height

a. ≤ 8m

1a, 1b, 2, 3a, 3b

b.> 8m

1b

6. Segments apex

a. Deeply bifid (as long or longer than ¼ of the total length of the segments)

1a, 3a, 3b

b. Entire to shortly bifid (shorter than ¼ of the total length of the segments)

1b, 2

c. Slightly to clearly spiny

1b, 2, 3a, (3b)

d. Not spiny

1a, (1b), (3a), 3b

Inflorescence

7. Peduncular bracts

a. Not fibrous-reticulate

1a, 1b, 2

b. Fibrous-reticulate

3a, 3b

Flowers

8. Sepals

a. Basal fusion <2/3 of their length

1a, 1b, 2

b. Basal fusion ≥ 2/3 of their length

3a, 3b

9. Petals

a. Loosely imbricate

1a, 1b, 2

b. Strongly contorted

3a. 3b

10. Stamens

a. Filaments length = anthers length (ratio 1:1)

1a, 1b

b. Filaments length> anthers length (ratio 2:1 to 3:1)

2, 3a, 3b

11. Gynoecium a. Ovary length = style length (ratio 1:1) 1a, 1b b. Ovary length <style length (ratio 1:2 to 1:3) 2, 3a, 3b

Fruit

12. Size

a. Small (0.6–1.2 cm)

3a, 3b

b. Medium to large (1.5–4 cm)

1a, 1b, 2

1. Trithrinax brasiliensis Martius (1837: 150) . Type:— BRAZIL. Rio Grande do Sul, Sellow s.n. (holotype M! ( Fig. 8 ), isotypes B, destroyed, G!, P!, fragment ex B at FI!)

Palms solitary (rarely clustered). Stem 1–13 m tall × 13.5–30 cm diameter (irregular in diameter when old), greyish and often with associated lichens, leaf scars, separated 3–5 cm; aerial roots rather smooth, light brown or greyish, 1–20 cm long × 0.2–0.5 cm of diameter. Leaves 15–35, lax to rigid; leaf sheath dark reddish or brown, greyish and smooth towards the apex, leaf sheath spines light brown to dark reddish, 4–18.3 cm long × 1–5 mm wide, rectangular in cross section; petiole 33–108 cm long × 0.9–3.5 cm wide; hastula 1–1.8 cm long × 2–3.5 cm wide adaxially and ca. 1 cm long × 2–3.5 cm wide abaxially; leaf blade, green, loosely covered with a white-waxy indumentum more abundant abaxially than adaxially, leaf blade regularly segmented, palman 0.4–9.5 cm (at the basal segments level) to 12.5–29.5 cm (median-apical segments level); leaf segments 27–46, with a lignified spiny or not lignified apex, basal segments 25.5–46.5 cm long × 0.7–2 cm wide, without or with an apical splitting of 0.9–44.5 cm, median segments 41–101 cm long × 1.5–3.4 cm wide, with an apical splitting of 1.6–47 cm, apical segments 46–113 cm long × 1.5–3.7 cm wide, with an apical splitting of 0.7–49 cm. Inflorescences 2–6, 40– 64 cm long, shorter than the leaves; peduncle 10–20 cm long × 1.7–3.5 cm wide; prophyll up to 22 cm long; peduncular bracts 2 (1–3), 8–26 cm long, at fruiting stage apart from each other 5.7–9.8 cm; rachis 34–67 cm × 0.4–3 cm wide at fruit stage, basal portion similar to the peduncle but pale green, the apical portion bearing about 30 rachillae; basal rachis-bracts 12–21.3 cm long, medial and apical rachis bracts about 7.5–10.5 cm long; branches 5–6 per inflorescence; branches apart from each other 3.2–12 cm, inserted 20–70° with respect to the rachis axis, basal branches up to 39 cm long × 20 cm wide, medial branches up to 31 cm long × 28 cm wide, apical branches up to 27 cm long × 21 cm wide; rachillae 35–52 per branch, inserted every 0.1–2 cm, subtended by bracts up to 0.5 cm long × 0.1–0.2 cm wide, basal rachillae 8.5–17 cm long × 0.1–0.3 cm wide at fruiting stage, inserted at 70–90° with respect to the branches axis, median-apical rachillae 4–9 cm long × 0.1–0.2 cm wide at fruiting stage, inserted at 45–90° with respect to the branches axis. Flowers inserted every 0.1–0.5 cm, each subtended by a 0.1–0.2 cm long × 0.1 cm wide floral bract; sepals 1–2 mm long × 1–2 mm wide; petals 1–3 mm long × 2 mm wide, not imbricate; stamens filaments 3–5 mm long; anthers 3–4 mm long × ca. 1 mm wide; gynoecium, carpels up to 2 mm long, ovary 1 mm long × ca. 0.5 mm wide, obovate, style less than 1 mm long × less than 1 mm wide. Fruits 2.1–4 cm of diameter, pale yellow, epicarp smooth, thin, mesocarp fleshy, endocarp thin; seed 1.1–2.2 cm of diameter.

Etymology: — brasiliensis : meaning Brazil, the home country of the material used by Martius for the original description of this species.

Distribution and ecology: —Distributed in southern Brazil in the states of Paraná, Rio Grande do Sul and Santa Catarina and in Paraguay, in the department of Alto Paraná ( Fig. 6 ). This species grows in lowland, open areas or clear forests in hilly regions from 200-950 m of elevation.

Taxonomic notes: — Trithrinax brasiliensis was the first species described for the genus on the base of a collection made by Sellow in the southern Brazilian state of Rio Grande do Sul (RS). In 1878, Drude described Trithrinax acanthocoma , based on a personal communication by Glaziou, who showed him this ornamental palm cultivated in Rio de Janeiro and in some European parks and for which natural populations were reported to be distributed in southern Brazil. Drude did not designate a type specimen in his publication; however, in his treatment of the palms for the Flora Brasiliensis ( Drude 1882) he complemented the description of T. acanthocoma and designated as type specimen a collection of Glaziou (9014, P). The definition of these two taxa has been controversial and they have been treated in different ways throughout history. Mattos (1977) described the palms of the Brazilian state of Rio Grande do Sul, and presented a new combination for Trithrinax acanthocoma , placing the taxon as a variety of T. brasiliensis . Unfortunately, this important publication has not been cited in the most recent publications dealing with the genus Trithrinax . In 1995, Henderson et al. placed T. acanthocoma as a synonym of T. brasiliensis and the most updated treatment of Brazilian palms by Lorenzi et al. (2010) reopened the debate by recognizing both names as independent specific entities. To clarify this situation, we visited the natural populations of both taxa, we analysed herbarium specimens, and we applied molecular phylogenetic methods ( Cano et al. unpublished). The resulting phylogeny lacked resolution at the specific and infraspecific levels ( Cano et al. unpublished), hindering any taxonomic decision. However, the morphological analysis of the specimens and fieldwork revealed several differences between them, especially regarding the vegetative morphology ( Tab. 1, key to the varieties of the species), and contrasting distribution patterns between the two taxa ( Fig. 6 ). Consequently, we adopt Mattos’ (1977) decision and recognise two varieties within the species: Trithrinax brasiliensis var. brasiliensis and T. brasiliensis var. acanthocoma .

Key to the varieties of Trithrinax brasiliensis

1. Leaf segments flexible and apically non-spiny, deeply bifid (11–49 cm) ..................................... 1a. var. brasiliensis .

- Leaf segments rigid and apically spiny, entire to shortly bifid (0.7–9 cm) .................................1b. var. acanthocoma .

1a. Trithrinax brasiliensis var. brasiliensis ( Fig. 7 ).

Stem 1–6 m tall; aerial roots forming a cone reaching up to 40 cm from the ground; leaves 15–30, lax to slightly rigid; leaf sheath spines 5–10 cm long; petiole 55–108 cm long × 0.9–2.5 cm wide; hastula ca. 1 cm long × ca. 2 cm wide adaxially and ca. 1 cm long × ca. 2 cm wide abaxially; leaf blade thin, light green, palman 0.4–2.0 cm (at the basal segments level) to 12.5–21.5 cm (median-apical segments level); leaf segments 27–43, flexible, with a bifid, acute, non-lignified apex, basal segments 25.5–46.5 cm long × 0.7–1.6 cm wide, with an apical splitting of 11.7–44.5 cm, median segments 44.2–84 cm long × 1.5–2.6 cm wide, with an apical splitting of 12–41 cm, apical segments 46–94 cm long × 2.1–3 cm wide, with an apical splitting of 12–49 cm. Inflorescences 2–6. Flowers 5 mm long; sepals 1 mm long × 1 mm wide, apex slightly acute; petals 1–2 mm long × 2 mm wide; filaments 3 mm long; anthers 3 mm long × ca. 1 mm wide; gynoecium up to 2 mm long, ovary 1 mm long × ca. 0.5 mm wide, style ca. 1 mm long × ca. 0.5 mm wide.

Distribution and ecology: —Restricted to southern Brazil, in the southern region of the state of Rio Grande do Sul ( Fig. 6 ). The palm grows in open areas or poorly dense, up to 8 m high forests, in hilly or rocky spaces. Also reported from riparian forests ( Soares 2009). This variety is present in lowland areas from 200 to 400 m of elevation ( Fig. 6 ).

Taxonomic notes: —The fruits of T. brasiliensis var. brasiliensis observed during our fieldwork were immature and measured 2.1–2.5 cm of diameter ( Fig. 7 ). The seeds measured 1.1–1.2 cm of diameter (obtained from Damazio-Silva s.n. (SP), a specimen with mature fruits). A different fruit size was given by Lorenzi et al. (2010), who reported a diameter of 1.5–2.5 and included a photo in which some fruits are mature, yellow, and measure about 3 cm of diameter.

S pecimens examined: — BRAZIL. Rio Grande do Sul: Sellow s.n. ( FI ex B, M, P); about 70 km N of Bagé on the BR 153, 200 m, Gibbons & Spanner 19964 ( M) ; Caçapava do Sul, Guaritas , 249 m, 30°50'06.4''S, 053°30'37.4''W, 18 February 2011, Reis, Cano et al. 2611 ( HBR) ; 74 km S de Caçapava do Sul ( BR153 , km 84), en Serranía , 7 December 1978, Krapovickas & Cristóbal 34220 ( CTES, G, ICN, K, MBM, NY, SI) ; Caçapava do Sul, 13 km al NW de Minas do Camaqua , 6 December 1978, Krapovickas & Cristóbal 34207 ( G, ICN) ; Quevedos, near Toropi's river , 286 m, 29°23'41.3''S, 054°01'19.9''W, 17 February 2011, Reis, Cano et al. 2607 ( HBR) ; Santo Antão, Santa María , 343 m, 29°37'35.6''S, 053°51'42.9''W, 19 February 2011, Reis, Cano et al. 2613 ( HBR) ; Saint-Hilaire 2764 ( P) . CULTIVATED. Brazil. São Paulo: Campinas , IAC, 5 Nov 2009, Lorenzi & Soares 6765 ( HPL) ; Parque Estadual das Fontes do Ipiranga ( Jardim Botânico ), Perto do hidrofitério, 25 November 1998, Kirizawa 3371 ( SP) ; Jardim Botânico de São Paulo, Perto do portão histórico e de bambuzal, 26 Mar 2001, Damãsio-Silva s.n. ( SP) .

Local names: — Carandá-moroty, carandá piranga, carandá-uba, carandahy ( Glassman 1972). Buriti, buriti-palito, carandaí, carandá ( Lorenzi et al. 2010).

Uses:— The leaves are employed in woven handcrafts ( Lorenzi et al. 2010) and as thatch. The fruits are used to prepare an alcoholic beverage. It is rarely used for ornamental purposes but has potential in this area ( Lorenzi et al. 2010).

Figures

FIGURE 5. Geographic distribution of the species of the genus Trithrinax. T. brasiliensis (green circles); T. campestris (yellow circles) and T. schizophylla (red circles).

FIGURE 6. Geographic distribution of Trithrinax brasiliensis and its two varieties T. brasiliensis var. brasiliensis (red circles) and T. brasiliensis var. acanthocoma (yellow circles).

FIGURE 7. Morphology of Trithrinax brasiliensis var. brasiliensis. A. Habit (Rio Grande do Sul, Brazil), scale bar: 30 cm; B. Leaf bade, scale bar: 10 cm; C. Detail of hastula (adaxial view), scale bar: 2 cm; D. Segment apex, scale bar: 10 cm; E. Inflorescence at full anthesis, scale bar: 10 cm; F. Scanning electronic micrograph of the flower, arrow pointing to the stigma, scale bar: 1 mm; G. Entire infructescence showing immature fruits, scale bar: 10 cm.

FIGURE 8. Holotype of Trithrinax brasiliensis, F. Sellow s.n (M), barcode: M0178215. Credits: herbarium G.

FIGURE 12. Morphology of Trithrinax campestris. A. Habit (Santiago del Estero, Argentina), scale bar: 50 cm; B. Leaf blade, scale bar: 10 cm; C. Detail of hastula (adaxial view), scale bar: 1 cm; D. Segment apex, scale bar: 2 cm; E. Scanning electronic micrograph of anthetic flower, arrow pointing to the stigma, scale bar: 2 mm; F. Flower at full anthesis, arrow pointing to the stigma, scale bar: 2 mm; G.Infructescence showing fruits at different developmental stages, scale bar: 10 cm; H. Ripe fruit showing perianth remnants, scale bar: 1 cm I. CS of the fruit and the seed, scale bar: 1 cm; J. Seed, scale bar: 1 cm; K. LS of seed showing the homogeneous endosperm, scale bar: 1 cm.

FIGURE 17. Morphology of Trithrinax schizophylla var. schizophylla. A. Habit (Salta, Argentina), scale bar: 60 cm B. Leaf blade, scale bar: 10 cm; C. Detail of hastula (adaxial view), scale bar: 1 cm; D. Segment apex, scale bar: 2 cm; E. Inflorescence at full anthesis, note the fibrous-reticulate apex of the peduncular and rachis bracts (Krapovickas 18645, CTES), scale bar: 10 cm; F. Scanning electronic micrograph of the flower, arrow pointing to the stigma, scale bar: 1 mm.