The World Flora Online

1. Crassula L.

Tillaea L.

Por F.R. Barrie.

Hierbas perennes o subarbustos, rara vez hierbas anuales; tallos típicamente suculentos, en Mesoamérica, cuando hierbas acuáticas o subacuáticas anuales, entonces glabras con tallos delgados no suculentos. Hojas opuestas, simples, las bases connatas y más o menos envainadoras; pecíolo ausente. Inflorescencias axilares, cimosas, las flores 2 o 3 o solitarias; brácteas 2, connatas basalmente. Flores sésiles, subsésiles o pediceladas, los pedicelos 1-4 mm; el cáliz de 3-5 sépalos, connatos basalmente; corola de 3-5 pétalos, libres; estambres 3-5; escamas del receptáculo 0.5-0.8 mm, filamentosas; carpelos 3-5, libres; óvulos 1-numerosos. Semillas 1-numerosas, las superficies lisas, estriadas y/o papilosas. Aprox. 200 spp. Continente americano, Europa, Asia, pero en su mayoría de Sudáfrica; 3 spp. en Mesoamérica.

Las aprox. 15 spp. americanas pertenecen a un grupo de hierbas anuales efímeras creciendo en ciénagas, acuáticas y subacuáticas, antes formalmente segregadas bajo el nombre de Tillaea. Sin embargo, estudios moleculares indican que el grupo está anidado dentro de Crassula (Thiede y Eggli, 2006). Las especies tienen extensas áreas de distribución pero solo han sido colectadas esporádicamente.

Bibliografía: Bywater, M. y Wickens, G.E. Kew Bull. 39: 699-728 (1984).

Source: [
• 1
• 10
]. 

Herbs [shrubs], annual or perennial, aquatic or terrestrial, not viviparous, 0.1-5 dm, glabrous [pubescent]. Stems erect, decumbent, or spreading, simple or branching, succulent. Leaves persistent or deciduous, cauline, opposite, sessile, connate basally; blade ovate, oblong, triangular to lanceolate or oblanceolate, or linear, laminar, 0.1-7 cm, fleshy, base not spurred, margins entire, with glands (hydathodes) in submarginal rows [scattered]; veins not conspicuous. Inflorescences thyrses or panicles [solitary flowers] in axils of leaves (flowers clustered when distal leaves smaller and crowded). Pedicels present. Flowers erect, 3-4(-5)-merous; sepals connate basally, all alike; petals spreading or recurved, distinct [connate], whitish; calyx and corolla not circumscissile in fruit; nectaries linear [various]; stamens as many as sepals; filaments free; pistils spreading to erect, distinct; ovary base rounded; styles 2+ times shorter than ovary. Fruits slightly recurved or ascending to erect. Seeds oblong or ellipsoid to reniform, ridged, sometimes also papillate. x = 8 (secondarily 7).

Source: [
• 11
]. 

Stamens equal in number to the petals, episepalous, or in gamopetalous corollas affixed to the tube; filaments often subulate, sometimes flattened; anthers ovate or oblong, sometimes with conspicuous connective

Source: [
• 8
]. 

Nectary scales usually very small, narrowly to broadly spathulate to obcuneate or square, rounded and slightly emarginate at the apex, rarely stipitate

Source: [
• 8
]. 

Carpels free or slightly united at the base; ovules numerous, rarely 1–2; styles often subulate, narrowly cylindrical or filamentous, often as long as the ovaries, or short and relatively thick; stigmata small, terminal or more rarely subdorsal.

Source: [
• 8
]. 

Annual or perennial herbs, rarely shrubs, frequently fleshy

Source: [
• 8
]. 

Petals usually slightly united at the base, white or red, rarely yellow or bluish; lobes stellate, erect, patent or connivent, apex often dorsally mucronate, the mucro small, hemispherical or cylindrical, usually blunt or conspicuous, ovoid or subglobular

Source: [
• 8
]. 

Sepals free or slightly united at the base

Source: [
• 8
]. 

Calyx usually much shorter than the corolla

Source: [
• 8
]. 

Flowers isomerous, 3–4- or 5-merous, rarely 6- or 9-merous

Source: [
• 8
]. 

Inflorescence usually corymbose, subumbellate, capitate or thyrsoid, sometimes an axillary fascicle or flowers rarely solitary

Source: [
• 8
]. 

Leaves very rarely absent, decussate, free or ± connate at the base to form a sheath around the stem, usually sessile, almost always entire, flattish, semiterete or subterete, glabrous, pubescent papillose or scabrid, margin smooth, ciliate or papillate

Source: [
• 8
]. 

Scales shorter than the carpels, hyaline or reddish-brown or rose, thin, narrowly to broadly spathulate or obovate or cuneate.

Source: [
• 9
]. 

Carpels free or connate at the base, oblong or obovoid, attenuate towards or contracted into a ± short usually terminal style, sometimes the styles nearly absent and stigmas subdorsal, completely glabrous or papillose along the suture; ovules numerous or sometimes 1-4.

Source: [
• 9
]. 

Stamens free or with the lower part of the filaments connate with the corolla-tube, alternipetalous; anthers ovate or oblong, sometimes nearly circular.

Source: [
• 9
]. 

Corolla usually white or whitish turning orange or brownish-red when dry, sometimes red or carmine, rarely bright yellow, persistent; petals erect or stellate, connate at the base into a ± short tube.

Source: [
• 9
]. 

Flowers (3-4)5(6-9)-merous, isomerous, usually small and not showy, in cymes arranged either in dense subsessile or pedunculate axillary clusters sometimes forming thyrsoid inflorescences, or in corymb-like axillary or terminal loose or ± dense inflorescences, sometimes 1(2) flowers in the leaf-axils.

Source: [
• 9
]. 

Calyx usually shorter than the corolla, with the sepals free or slightly connate at the base, appressed to the corolla, ± succulent.

Source: [
• 9
]. 

Annual or perennial succulent herbs, sometimes with a tuber-like root, or undershrubs or shrubs with ± woody root-stock and succulent usually ± fleshy leaves.

Source: [
• 9
]. 

Leaves opposite, usually decussate, the lowermost frequently rosulate, free or ± connate in a sheath, usually simple, undivided and entire, thin to ± thick, flat, terete, semiterete, ovoid, etc.

Source: [
• 9
]. 

Plantes'herbacées, annuelles ou vivaces, à tiges charnues ou plantes semi-arbustives.'Tiges'± ligneuses; racines fréquemment tubéreuses.'Feuilles'décussées, libres ou ± connées à la base, ordinairement sessiles, presque toujours entières, planes, semi-cylindriques ou cylindriques, glabres, papilleuses ou scabres, à marge lisse, ciliée ou papilleuse.'Fleurs ordinairement disposées en inflorescences corymbeuses subombellées, capitées ou thyrsoïdes, rarement solitaires, isomères, haplostémones, le plus souvent 5-mères, rarement 3-4-mères, plus rarement 6-9-mères; calice en général plus court que la corolle, à sépales libres ou légèrement soudés à la base; pétales presque toujours soudés à la base, étalés ou érigés, récurvés ou confluents au sommet, le plus souvent mucronulés ou pourvus d'un appendice épaissi ± globuleux ou capité; étamines épisépales à filet inséré sur le court tube corollin (chez les espèces gamopétales) filiformes ou légèrement cunéées; anthère sovales ou oblongues; carpelles libres ou un peu soudés à la base, rétrécis en un style subulé aussi long ou plus court que l'ovaire; ovules nombreux, rarement 1-2; squamules nectarifères, plus petites que l'ovaire, obcu-néées, arrondies et légèrement émarginées.\n\t\t\t\tCe genre renferme environ 300 espèces, la plupart (230) réparties en Afrique du Sud, les autres en Afrique orientale, en Arabie, à Mada-gascar, en Europe et en Amérique.\n\t\t\t\tLa révision systématique de la section des'Tillaeoideae infirmera ou confirmera les larges répartitions de certaines espèces.

Source: [
• 13
]. 

SELECTED REFERENCES Bywater, M. and G. E. Wickens. 1984. New World species of the genus Crassula. Kew Bull. 39: 699-728. Merxmüller, H., H. C. Friedrich, and J. Grau. 1971. Cytotaxonomische Untersuchungen zur Gattungsstruktur von Crassula. Ann. Naturhist. Mus. Wien 75: 111-119. Moran, R. V. 1992b. Pygmyweed (Crassula connata) etc. in western North America. Cact. Succ. J. (Los Angeles) 64: 223-231. Toelken, H. R. 1977. A revision of the genus Crassula in southern Africa. Contr. Bolus Herb. 8. Van Jaarsveld, E. J. 2003. Crassula. In: U. Eggli, ed. 2003. Illustrated Handbook of Succulent Plants. Crassulaceae. New York. Pp. 32-84.

Source: [
• 11
].