Bonamia

Accepted name/Authority/Place of publication: 

Bonamia Dupetit-Thouars, Hist. Veg. Isl. France Reunion, Madagascar 1: 33, pl. 8. 1804, nom. cons.

Tribe: 
Cresseae
Synonyms: 

Breweria R. Br., Prodr. Fl. Nov. Holl. 487. 1810. Type species: Bonamia linearis (R. Br.) Hallier f. (as Breweria linearis R. Br. 1810)

Trichantha Karst. &Triana, Linnaea 28: 437. 1856. Type species: Bonamia trichantha Hallier f. (as Trichantha ferruginea Karst. &Triana, 1856); not Trichantha Hooker, Icon. Pl. plates 666, 667. 1844.

Perispermum Degener, Flora Hawaiiensis, Fam. 307. 1932. Type species: Bonamia menziesii A.Gray (as Perispermum albiflorum Degener, 1932)

Breweriopsis G. Roberty, Candollea 14: 31. 1952. Type species: Bonamia elegans (Wall.) Hallier f. (as Breweriopsis elegans (Wall.) Roberty, 1952).

Type Species: 

B. madagascariensis Poiret in Lamarck, Encycl. Meth. Bot. suppl. 1: 677. 1810, nom. illeg. (B. alternifolia J. St. Hilaire, Expos. Fam. 2: 349. 1805.)

Habit: 
Perennial, herbaceous, suffrutescent or woody, twining, prostrate or trailing, occasionally procumbent or suberect, shubby vines or erect subshrubs; shoots a few to several, simple or branched, growing all year around or arising annually from old shoots, bases of previous shoots, crowns, horizontally spreading subterranean stems, or from roots. Roots deep-penetrating, often becoming thick in some, frequently with pulpy bark, never bulbous nor fleshy. Steams at the base, as long as a few decimetres to several meters in height, smooth or lenticellate, glabrous to densely pubescent, villous, sericeous or ferrugineous.
Leaves: 
Leaves petiolate, subsessile or sessile, estipulate, herbaceous or subcoriaceous, occasionally leathery; blades simple, entire, occasionally undulate or slightly wavy, ovate, ovate-cordate, elliptic, ovate-elliptic, oblong-ovate, lanceolate, oblong, linear or linear-lanceolate, often large, acute, obtuse, acuminate, acute-mucronate, obtuse-mucronate or slightly emarginated at the apex, acute, attenuate, cordate, rounded or truncate at the base; veins prominent to inconspicuous except the midribs, mostly impressed above, often with distinct intercostals veins; hairs appressed, two-armed, straight or crisped, very fine to distinctly long, scattered or dense, silvery grey, greyish white, pale brown or grey, often becoming rusty brown when dry.
Inflorescences: 
Inflorescence axillary or terminal, pedunculate or subsessile, simple or compound dichasial cymes of few to several flowers, often solitary or terminal panicles composed of several dichasial cymes; peduncles short or elongate, usually shorter than leaves, or absent; pedicels usually short, occasionally elongate (becoming as long as 2 cm.); bracts small and linear or distinctly foliaceous, mostly two for each individual flower, opposite or slightly alternate, sometimes crowded in congested clusters.
Flowers: 
Sepals five, quincuncially imbricate, free or rarely united at the extreme base, mostly ovate, ovate-lanceolate, broadly lanceolate orbicular, or oblong-orbicular, equal or unequal, acute, acuminate, obtuse, rounded or slightly emarginated at the apex, sericeous, tomentose, pilose, velutinous, ferrugineous or glabrous on the inner surface, persistent in capsules. Corolla white, blue, bluish purple, pink or red, yellow, yellowish white or greenish white, funnel-shaped, petalous with entire, subentire, lobed or lobulate limb, outside sparsely or densely pilose on interplicae (midpetaline bands), glabrous on plicae (infolded areas); individual hairs on interplicae with two unequal arms (long arms directed toward apices of petals). Stamens five, alternate with petals, inserted or rarely exserted, all fertile; filaments epipetalous (being adnate to the lower, narrow part of the corolla), straight, filiform or somewhat dilated below, dorsiventrally flattened, unequal, subequal or equal in length, glabrous or thinly to densely villous or glandular-villous (with crisped or curly hairs), frequently villous only on the basal dilated portions; anthers two-celled, oblong or oblong-lanceolate, dorsifixed or apparently basifixed, frequently sagittate or cordate at the base, introrse or partially extrorse by vertically dehiscing slits; pollen colpate and punctitegillate, not spiniferous. Ovary superior, bi carpellate, bilocular, long-pilose or hirsute with two-armed hairs (both arms of each hair directing toward the mouth of the corolla) or glabrous, surrounded by annular disc at the base; ovules two in each loculus, erect, anatropous, in axile placentation, appearing to be basal; styles terminal, two, almost free to partially united, included in the corolla to partially exserted; stylar branches (or stylodia) equal to unequal, filiform, mostly glabrous, occasionally with scattered hairs; stigmas large or small, globose, subglobose, capitate, reniform, bilobed conical or rarely peltate, smooth or rugose, occasionally lobulate.
Pollen: 
Pollen colpate and punctitegillate, not spiniferous.
Fruits: 
Fruit 1- to 4-seeded, 4- to 8- valvular, rarely 2-valvular capsules with thin and chartaceous or thick and ligneous walls, ovoid, globose or conical-ovoid, apiculate at the apex, glabrous or with scattered hairs, two-celled with thin or thick septum, with persistent sepals, dehiscing by valves, occasionally dehiscing by circumcision, rarely remaining indehiscent for a long time after ripeness.
Seeds: 
Seeds brown, dark brown or black, smooth or punctuate, glabrous or lanate, oval and plano-convex or roughly three-angled, with hard or rarely soft seedcoat, covered with thin transparent persisperm; endosperm thin, foliaceous, ovate, obovate, ovate-cordate or orbicular, corrugate-plicate and folded against radicle or simply flat or slightly folded along central line and folded against radicle; cotyledonary petioles free or fused.
Chemical Data: 

In principal to date there are reports on secondary metabolites of 5 species, Bonamia brevifolia, Bonamia dietrichiana, Bonamia semidigyna, Bonamia spectabilis, Bonamia trichantha :

Simple pyrrolidine alkaloids: constituents of all 5 spp.

Tropane alkaloids: constituents of 4 spp. (absent in B. dietrichiana).

Calystegines: constituents of B. semidigyna, B. spectabilis; absent in B. dietrichiana, B. trichantha (B. brevifolia not checked).

Nicotine: constituent of B. semidigyna, B. spectabilis, B. trichantha; absent in B. brevifolia, B. dietrichiana.

Different phenylpropanoids: B. semidigyna (remaining species not checked).

Moreover, novel metabolites unique in the plant kingdom were discovered in the following species:

Bonamia semidigyna: benzofurans substituted by a hemiterpenoid (bonaseminols).

Bonamia spectabilis: (i) esters of 3α-hydroxytropane with monoterpenoid acids (bonabilines); (ii) sesquilignans/sesquineolignans (bonaspectins/neobonaspectins).

Bonamia trichantha: long chain alkyl esters of hydroxycinnamic acids (trichanthins).

For details including chemical structures and references see the corresponding species sites.

Eckart Eich

Distribution: 

Pantropical. map

Number of Species: 
56
Other information: 
Flowering from summer to winter.

Author/Editor

Author: 
T. Myint & D.B. Ward
Editor: 
G.W. Staples
Publication: 

MYINT, T., & WARD, D.B., 1968. A taxonomic revision of the genus Bonamia (Convolvulaceae). Phytologia 17: 121-239.

Contributors: 
Classification: 
Bonamia

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