Haynes, R. R. and L. B. Holm-Nielsen. 1994. The Alismataceae. Flora Neotrop. Monogr. 64: 1-112.

Novelo R., A. and A. Lot H. 1994. Alismataceae. Pp. 3-8 in Davidse, G., Sousa, M. and Chater, A. (eds.). Flora Mesoamericana 6: 1-543. Universidad Nacional Autónoma de México: México, D. F.

 

12 genera, ca. 110 spp.; nearly cosmopolitan; 2 genera, 9 spp. in CR.

Perennial, or sometimes annual; aquatic herbs. Rooted, emergent, floating or submersed. Plants monocious (CR), dioecious, or hermaphroditic (CR). Stems short, with leaves basal, often rhizomatous, sometimes producing corms at tips. Juvenile leaves linear-subulate. Adult leaves linear-subulate, to linear and submersed, or petiolate and floating or emergent, blades linear to linear lanceolate to ovate, base sagittate, hastate, cordate or attenuate. Inflorescence often compound with whorls of branches, sometimes simple, rarely umbelliform or solitary flowers. Flowers actinomorphic. Sepals 3, persistent. Petals 3. Stamens 3 or 6-many (CR). Carpels 3 or more, typically numerous (CR), ovary superior. Fruit an achene.

1. Flowers bisexual; inflorescences mostly with more than 3 flowers per whorl, or umbelliform; fruits terete, ribbed, often with glands...Echinodorus

1. Flowers unisexual; inflorescences mostly with only 3 flowers per whorl; fruits laterally flattened, smooth or with 1-2 glands and/or 1-3 lateral wings (sometimes echinate, see fig. ___)...Sagittaria

Rataj. K. 1975. Revizion of the genus Echinodorus Rich. Stud. Ceskoslov. Akad. Ved. 2: 1-156.

 

Plants perennial or annual; hermaphroditic. Rooted, emergent or stranded on wet margins. Roots not septate. Leaves basal, mostly petiolate, blades linear to broadly ovate, attenuate to truncate or cordate at base, in some spp. blades with pellucid marks (short lines or dots, seen when held to light). Inflorescence simple or branched, with several whorls. Flowers bisexual. Sepals 3, persistent. Petals 3, white (rarely pinkish), usually twice as long as sepals. Stamens (6-)9-30, anthers basifixed or versatile. Carpels numerous, usually densely crowded. Fruiting head globose to somewhat longer than broad; achenes terete, ribbed, often with 1-several glands between the ribs, persistent style forming a beak.

Echinodorus macrophyllus (Kunth) Micheli ssp. scaber (Rataj) R.R. Haynes & Holm-Neils., included (as E. scaber Rataj var. scaber) for CR in Flora Mesoamericana (Lot and Novelo, 1994) is based on a misidentified specimen of E. bracteatus (Herrera 1751, CR, MEXU, MO). No other material of this species has been seen for CR, therefore it has been excluded in this treatment. Furthermore, Flora Neotropica (Haynes and Holm-Nielsen, 1994) cite only one collection for Central America, that being a Haynes collection from Nicaragua.

Echinodorus grandiflorus (Cham. & Schldl.) Micheli ssp. grandiflorus, similar to E. bracteatus, but with achenes having a longer beak (0.5-1 mm long) and leaves with pellucid marks represented only as lines, has been recorded from both Nicaragua and Panama and might be expected in CR.

1. Plants small, mostly less than 15(-30) cm tall; carpels/fruits 20 or fewer, in a loose ring-like head; stamens (8-)9, anthers basifixed...E. bolivianus

1. Plants large, mostly much more than 30 cm tall; carpels/fruits numerous, in a dense globose to slightly oblong head; stamens 12-30, anthers versatile.

2. Leaf blades very broad, mostly (7)15-60 cm wide, cordate or truncate to somewhat auriculate at base.

3. Inflorescence simple; fruiting heads large, 10 X 13-15 mm; sepals totally enclosing fruiting head; achenes 2.6-3.2 mm long, beak ca. 0.5-0.7 mm long...E. tunicatus

 

3. Inflorescence branched at lowest or more whorls; fruiting heads smaller, 5-8 X 6-10 mm; sepals not enclosing or partially (at most only half) enclosing fruiting head; achenes 2.2-2.5, beak ca. 0.2-0.3 mm long...E. bracteatus.

 2. Leaf blades more narrow, mostly 2-9 cm wide, attenuate at base.

4. Stamens ca. 20; inflorescence usually branched; achenes lacking glands on lateral face...E. paniculata

 

 4. Stamens 9-12; inflorescence simple (rarely branched at bottom); achenes with 1 or more glands on lateral face.

 

 5. Plants somewhat delicate, flowers distinctly long pedicellate, bracts shorter than pedicels; fruiting heads 3.5-4 X 3.5-4 mm long; achenes 1.2-1.6 mm long, beak 0.2-0.3 mm long, lateral face with 5 or more glands...E. grisebachii

 

 5. Plants robust, flowers short-pedicellate, bracts longer than pedicels; fruiting heads 6-10 X 5-9 mm; achenes 1.8-3, beak 0.5-1.5 mm long, lateral face with 1-2 glands...E. subalatus

 Echinodorus bolivianus (Rusby) Holm-Nielsen, Brittonia 31: 276. 1979. [Alisma bolivianum Rusby, Mem. New York Bot. Gard. 7: 208. 1927; E. latifolius (Seub.) Rataj; E. isthmicus Fassett; E. tenellus (Schult. f. ex Mart.) Buchenau var. latifolius (Seub.) Fassett].

Annuals, small, up to 30 cm tall, mostly less than 15 cm, rhizomatous, fertile plants emergent or more often, stranded on wet margins. Leaves submersed or emergent, linear to linear-lanceolate, petioles mostly 1-7(-25) cm long, blades 1.3-7(22) cm long, without pellucid marks, attenuate at base. Inflorescence simple, with 1-2 whorls, 4-11 flowers. Pedicels long, 0.8-3.5(5) cm long. Sepals 2.8-4.3 mm long. Petals white, about 2 times the length of the sepals. Stamens mostly 9. Carpels few, 20 or less. Fruits a loose, ring-like head, enclosed by the persistent sepals, achenes 1-1.7 mm long, usually with 2-3 well developed facial ribs (sometimes absent).

Mostly wet shores of lakes and lagunas, especially with fluctuating water levels. Valle General [Gómez 19696, CR, MO], Cañas Gordas [Pittier 11126 M, Gr, G, cited in Flora Mesoamericana and Flora Neotropica], fertile Jan.; Eastern U.S. to Bolivia and Paraguay.

The material from Costa Rica fits Fassett's concept of E. latifolia Fassett; Flora Mesoamericana (Lot & Novelo, 1994) treats this taxon within their concept of E. tenellus, while Flora Neotropica (Haynes & Holm-Neilsen, 1994) treats it within their concept of E. bolivianus. After examining material of both E. tennellus and E. bolivianus from South America, it seems appropriate to maintain the two taxa as distinct and include the name E. latifolia in synonomy under E. bolivianus. However, the distinction of these two taxa appears to be based on minor characters and it may be more appropriate to recognize one wide-ranging species with two subspecies.

Echinodorus bracteatus Micheli, in A. DC. & C. DC., Monogr. phan. 3: 59. 1881.

Perennials, emergent. Leaves erect, petioles up to 80 cm long; blades ovate, with pellucid dots and lines, cordate to truncate-auriculate at base, 25-45 cm long, 15-30 cm wide. Inflorescence branching at one or more whorls, whorls 8-20, each with 3-8 flowers. Fruiting heads 5 X 6-7 mm, obovoid, covered to about the middle by sepals; achenes 2.2-2.5 mm long, beak 0.2-0.3 mm long, glands 1-2(-4) on lateral face.

Marshes, open swampy sites. Llanura Guatusos [Burger, Barringer & Gómez-L. 11803, MO, F], fertile Feb. Nicaragua to Ecuador.

Echinodorus grisebachii Small, in Britton, N. Amer. fl. 17(1): 46, fig. 15. 1909.

Short-lived perennials, submersed to emergent. Submersed leaves thin, linear. Leaves erect, petioles 8-20 cm long; blades lanceolate, with pellucid lines, attenuate at base, 8-11 cm long, 2-3 cm wide. Inflorescence simple, rarely branching at base, whorls (4-)5-9(-11), each with 3-9(-11) flowers. Fruiting heads 3.5-4 X 3.5-4 mm, globose-ovoid; achenes 1.8-3 mm long, beak 0.5-1.5 mm long, 1-2 glands on lateral face.

Marshes, open swampy sites. Colorado de Coto [Valerio 1389, F], Llanura Tortuguero [Stevens Herrera & Montiel 24741, MO], fertile Mar. Honduras to Bolivia and Brazil; Cuba.

Echinodorus paniculatus Micheli, in A. DC & C. DC., Monogr. phan. 3:51. 1881.

Annuals or short-lived perennials, emergent. Leaves erect, petioles 15-70 cm long; blades narrowly to broadly lanceolate, lacking pellucid marks, attenuate at base, 9-42 cm long, 2-7.5 cm wide. Inflorescence usually branched at lower whorls, sometimes simple, whorls 4-8, each with 6-16(-35) flowers, flowers pedicellate, bracts mostly shorter than or equalling the pedicels, few exceeding. Fruiting heads 4-5(-8) X 4-5(-9) mm, globose; achenes 1.5-2.2 mm long, beak 0.3-0.5(-0.7) mm long, lacking glands on lateral face.

Sometimes confused with E. subalatus ssp. andrieuxii, E. paniculata can be readily distinguished by it's compound inflorescence and smaller fruiting heads.

Marshes, swampy sites. Llanura Guatusos, Valle Tempisque [Crow & Rivera 6059, CR, MO, NHA], fertile Apr., May, Jun., Aug., Sept. S. Mex. to Paraguay and n. Argentina.

Echinodorus subalatus (Schult. f. ex Mart.) Griseb., Cat. pl. Cub. 218. 1866. [Alisma subalatum Schult. f. ex Mart. in Roem. & Schult., Syst. Veg. 7: 1609. 1830.].

Short-lived perennials, emergent. Leaves erect, petioles 5-35 cm long; blades elliptic to ovate, lacking pellucid marks, attenuate at base, 5-35 cm long, 2.3-9 cm wide. Inflorescence simple, rarely branching at base, whorls 3-20, each with 3-20 flowers, flowers short-pedicellate, with bracts longer than the pedicels. Fruiting heads 6-10 X 5-9 mm, globose to ovoid; achenes 1.2-1-6 mm long, beak 0.2-0.3 mm long, 5 or more glands on lateral face.

Although typically with unbranched inflorescences, specimens with branching may be confused with E. paniculata, however the latter has flowers conspicuously pedicellate and smaller fruiting heads (mostly 4-5 X 4-5 mm, globose).

Our taxon is ssp. andrieuxii (Hook. & Arn.) R.R. Haynes & Holm-Niels. Flora Mesoamericana (Lot and Novelo, 1994) treats this taxon as a distinct species, E. andrieuxii, while Flora Neotropica (Haynes and Holm-Nielsen, 1994) treats it as conspecific with E. subalatus, but distinct at subspecific rank. However, after examining Central and South American specimens of both of these taxa, it is questionable if even subspecific distinction is warranted.

Marshes and swampy sites. Guanacaste lowlands (Santa Rosa Nat. Park) [Sousa et al. 12697, MO], fertile Jan., Nov. Mex. to CR; Venezuela, se. Brazil.

Echinodorus tunicatus Small, in Britton, N. Amer. fl. 17(1): 48, fig. 32. 1909.

Perennials, emergent. Leaves erect, petioles 15-90 cm long; blades ovate, with pellucid dots and lines, cordate to somewhat auriculate at base, 10-40 cm long, 7-28 cm wide. Inflorescence simple, whorls 2-10, each with 6-20 flowers. Fruiting heads 10 X 13-15 mm, oblong, totally covered by sepals; achenes 2.6-3.2 mm long, beak 0.5-0.7 mm long, glands 3(-5) on lateral face.

Marshes and open swampy sites. Llanura Tortuguero, Limón [Grayum & Flores 9120, CR, MO], fertile Jun., Nov. CR to Bolivia.

Rataj, K. 1972. Revision of the genus Sagittaria. Part II. (The species of the West Indies, Central and South America). Annot. Zool. Bot. 78: 1-61.

 

Ca. 25 spp.; mostly New World, with ca. 4 spp. in Old World; 3 spp. in CR.

Plants perennial or sometimes annual, arising from corms or rhizomes; monoecious or rarely dioecious. Rooted, emergent or stranded on wet margins. Roots septate. Stems short, leaves basal, spreading by rhizomes, rhizomes sometimes terminated by perennating tubers. Leaves submersed, floating, or often emergent, with or sometimes without petioles. Blades linear to linear-lanceolate to ovate to elliptic, bases attenuate, sagittate, hastate, or somewhat cordate; lacking pellucide marks. Inflorescences racemose or paniculate, rarely umbelliform, with 1-12 whorls, 2-3 flowers per whorl. Flowers unisexual, 3-merous, sepals green, petals white. Staminate flowers with stamens 7-many. Pistillate flowers with numerous carpels. Fruiting head globose to slightly wider than long; achenes laterally flattened, lateral surface smooth, or with 1-few glands and/or 1-3 lateral wings (sometimes echinate), persistent style forming a beak.

1. Plants with leaves and inflorescence floating...S. guayanensis

1. Plants with leaves and inflorescence emergent.

2. Leaf blades very narrow, 0.1-0.3 cm wide; sepals appressed around fruiting head; pedicels spreading to recurved and thickened, in fruit...S. rhombifolia

 

2. Leaf blades wider, 0.7-20 cm wide; sepals reflexed from fruiting head; pedicels ascending, not thickened in fruit.

3. Leaves with basal lobes lacking, tapering to base; plants always monoecious...S. lancifolia

 

3. Leaves with basal lobes, sagittate at base; plants often dioecious...S. latifolia

Sagittaria guayanensis Kunth, in Humb., Bonpl. & Kunth, Nov. gen. sp. 1: 250. 1816. [Lophotocarpus guayanensis (Kunth) J. G. Sm.].

Perennials, submersed or floating, arising from corms, monoecious. Submersed leaves sessile, phyllodial. Floating leaves petiolate, blades elliptic to nearly orbicular, cordate (with lobes ending in tips similar to Nymphaea) to broadly sagittate at base. Inflorescence simple, with 1-7 whorls, usually floating. Flowers 3 per whorl. Staminate flowers in upper whorls; stamens 9-12, sterile carpels present. Pistillate flowers in lower whorls; carpels numerous, with ring of sterile stamens. Fruiting heads 0.6-0.7 X 1-1.5 cm, wider than long, pedicels spreading or recurved, sepals appressed around fruiting head.; achenes 1.7-2.2 mm long, beak erect, 0.2-0.5 mm long, 1-3 lateral wings with margins echinate, glands absent.

The New World taxon is ssp. guayanensis.

Lagunas and temporary ponds. Llanura Guatusos, Valle Tempisque, Guanacaste lowland (Santa Rosa Park) [Crow & Rivera 6279 CR, MO, NHA], fertile Sept., Nov. Mex. to Paraguay and n. Argentina.

Sagittaria lancifolia L., Syst. nat. ed. 10 1270. 1759.

Perennials, emergent, arising from rhizomes, monoecious. Emergent leaves petiolate, blades linear to ovate to elliptic, attenuate at base. Inflorescence simple or paniculate, with 6-13 whorls, emergent. Flowers 3 per whorl. Staminate flowers in upper whorls; stamens 20 or more, with sterile carpels absent. Pistillate flowers in lower whorls; carpels numerous, without a ring of sterile stamens. Fruiting heads 0.8-1.1 X 1.1-1.5 cm, globose to slightly wider than long, pedicels ascending, sepals reflexed; achenes 1.6-2.5 mm long, beak erect 0.3-0.7 mm long, lateral surface with 1 gland.

Open swampy sites, river margins, marshes. Subspecies media (Micheli) Bogin, with bracts and sepals papillose is known from only from Barra del Colorado [Davidse & Herrera 30895 CR, MO; Stevens 24161, MO], fertile Jan., Sept.; ssp. lancifolia, with bracts and sepals lacking papillae, is included by Flora Mesoamericana (Lot and Novelo, 1994), citing Pittier 6822 (CR). Mex. to Ecuador, Venezuela and Brazil.

Sagittaria latifolia Willd., Sp. pl. 4: 409. 1805. [S. latifolia var. pubescens (Muhl.) J. G. Sm.].

Perennials, from rhizomes or corms, monoecious or dioecious. Emergent leaves petiolate, blades linear to broadly ovate, lobed at base, sagittate. Inflorescence simple, rarely paniculate, with 3-9 whorls, emergent; staminate flowers in upper whorls, or frequently the inflorescences unisexual. Flowers 3 per whorl. Staminate flowers without sterile carpels; stamens 16-18. Pistillate flowers with carpels numerous, without a ring of sterile stamens. Fruiting heads 1-1.3 X 1-1.5 cm, slightly wider than long; pedicels ascending, sepals reflexed; achenes 2.5-3.5 mm long, beak lateral, horizontal, 1-2 mm long, lateral surface smooth or with 1(-2) glands.

Although varieties have been recognized based on the presence or absence of pubescence, Haynes and Holm-Nielsen (1994) do not believe that this character alone is worthy of taxonomic recognition.

Open swampy sites, river margins, marshes. Reported only from Marais de Matina [Pittier 10304, G, cited in Fl. Mesoamer.]. Canada to N. S. Am.; Antilles.

Sagittaria rhombifolia Cham., Linnaea 10: 219. 1835. [Echinodorus botanicorum L. D. Gómez & Gómez-Laur.].

Perennials, from rhizomes or corms, submersed or emergent, monoecious. Submersed leaves sessile, linear, ribbon-like, 10-50 cm long, 1-3 mm wide. Emergent leaves peltiolate, the blades linear to linear-lanceolate, lance-ovate to rhombiform, to rarely sub-cordate, typically tapering to base, basal lobes absent. Inflorescence simple, with 2-10 whorls. Flowers 2-3 per whorl. Staminate flowers in upper whorls; stamens 9-12, sterile carpels present. Pistillate flowers only in lowermost whorl, without ring of sterile stamens. Fruiting head (1-)2.5-3 X 1 cm, wider than long, pedicels spreading to recurved, thickened, sepals appressed around fruit; achenes (3.2)5-7 mm, beak lateral, 0.7-1.2 mm long, lateral surface smooth.

Lagunas. Known only from laguna at Buenos Aires, Valle General [Crow & Rivera 6255, CR, MO, NHA], fertile Jan., Sept., Nov. CR to Paraguay and n. Argentina.