Launaea

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Description

Perennial to pauciennial herbs, small rosette shrubs, subshrubs, spinescent shrubs or annuals, all taprooted and roots often shootbearing. Leaves sessile, commonly rosetted at least in juvenile plants, sometimes leaf development preceded by anthesis; adult herbaceous plants often with sessile and frequently clasping to auriculate cauline leaves, aging subfrutescent or frutescent plants sometimes leafless; lamina of saladlike consistency or somewhat leathery, more rarely somewhat succulent, rarely ±entire, usually sinuate-dentate to variously pinnatifid, more rarely bipinnatifid, often denticulate, teeth frequently white-cartilagineous. Synflorescence mostly with inconspicuous bracts only, sometimes with smaller, cauline leaves; either (sub)acaulescent and tufted or glomerate, rarely subscapose, or, more frequently, caulescent; caulescent synflorescences either few-capitulate or ±many-capitulate and divaricate, herbaceous, or indurate and ±spinescent, or virgate or glomerate. Peduncles sometimes greatly reduced, usually little differentiated from preceding branches and with few to several bracts grading into the outer involucral bracts, usually spreading erect, rarely nodding in bud or at fruiting time; in indurate synflorescences usually subulate and persisting as spinelike segments after the shedding of the capitula. Capitula mostly slender and with c. 7-40 flowers, sometimes (sub)globose with up to > 100 flowers. Receptacle flat to slightly convex, epaleate, glabrous, very indistinctly areolate and pitted. Involucre with ±imbricate, usually ovate-acute to lanceolate outer bracts and a single row of linear-lanceolate inner bracts of ±equal length at anthesis. Inner bracts either being 5 or 8 and ±constant in number, or varying between either (3)4- c. 8 or c. 8-12(14); either prolonged after anthesis and then becoming ±unequal in length, or not prolonged. Fruiting involucre (6-)1o-16(-25) mm long. Flowers with a narrowly spathulate to linear, (4-)6-12(-20) mm long ligule of some shade of yellow, sometimes ±tinged red or violet on fading. Corolla tube pubescent with unicellular trichomes in upper part, shorter than the ligule or equalling the ligule in length, rarely little longer. Anther tube proper (0.8-)2-4(-4.8) mm long, and with rounded apical and sagittate basal appendages. Style branches 0.5-3.0(-4.0) mm long, yellow, with either concolourous or blackish sweeping hairs. Achenes ±cylindric to columnar, ±cuneate in outline or ±subfusiform, either subterete or prismatic, truncate or cuspidate to short- or long-rostrate, (1.6-)3-7(-12) mm long, ±homomorphic to moderately heteromorphic; either all with five main ribs, each usually accompanied by one ±distinct secondary rib on either side, or inner with four and outer with five main ribs, and capitula either with a higher ratio of the first or the second type; marginal achenes often somewhat compressed and curved, glabrous or variously papillose, their ribs smooth or, more commonly, with narrow transverse wrinkles of various shapes, the innermost achenes at the same time often ±smooth, or ±glabrous. Pappus (3.5-)5-9(-14) mm long, white and soft, (sub)homomorphic with only setaceous rays and persistent to cacduous, or dimorphic and usually persistent, with downy outer and setaceous inner rays, or with numerous cottony rays and setaceous rays may or may not be present.

based on: Kilian in Englera 17: 83-84, 1997.

Distribution

Africa: Aldabranative; Algerianative; Angolanative; Beninnative; Burkinanative; Burundinative; Cameroonnative; Canary Is.native; Cape Verdenative; Central African Republicnative; Chadnative; Comorosintroduced; Congonative; Djiboutinative; Egyptnative; Eritreanative; Ethiopianative; Gambia, Theintroduced; Ghananative; Guineanative; Gulf of Guinea Is.native: doubtfully native; Ivory Coastnative; Kenyanative; KwaZulu-Natalnative; Libyanative; Madagascarnative; Madeiranative; Malawinative; Malinative; Mauritanianative; Mauritiusnative; Mozambiquenative; Namibianative; Nigernative; Nigerianative; Northern Provincesnative; Rwandanative; Réunionnative; Senegalnative; Seychellesnative; Sierra Leonenative; Socotranative; Somalianative; Sudannative; Tanzanianative; Togonative; Tunisianative; Ugandanative; Western Saharanative; Zairenative; Zambianative; Zimbabwenative Asia-Temperate: Afghanistannative; China North-Centralnative; China South-Centralnative; China Southeastnative; Cyprusnative; Gulf Statesnative; Hainannative; Inner Mongolianative; Irannative; Iraqnative; Kazakhstannative; Kuwaitnative; Lebanon-Syrianative; Omannative; Palestinenative; Saudi Arabianative; Sinainative; Tadzhikistannative; Turkmenistannative; Uzbekistannative; Xinjiangnative; Yemennative Asia-Tropical: Andaman Is.native; Assamnative; Bangladeshnative; East Himalayanative; Indianative; Jawanative; Laosnative; Maldivesnative; Myanmarnative; Nepalnative; Pakistannative; Sri Lankanative; Thailandnative; Vietnamnative; West Himalayanative Australasia: Western Australianative Europe: Balearesnative; Sicilynative; Spainnative Northern America: Floridaintroduced; Mexico Northeastintroduced; Mexico Northwestintroduced; Mexico Southeastintroduced; Mexico Southwestintroduced; Texasintroduced Southern America: Arubaintroduced; Bahamasintroduced; Cayman Is.introduced; Colombiaintroduced; Cubaintroduced; Dominican Republicintroduced; Guatemalaintroduced; Haitiintroduced; Jamaicaintroduced; Leeward Is.introduced; Netherlands Antillesintroduced; Peruintroduced; Puerto Ricointroduced; Trinidad-Tobagointroduced; Turks-Caicos Is.introduced; Venezuelaintroduced; Venezuelan Antillesintroduced; Windward Is.introduced

Common names

Arabic (Lebanon): لونييَةA,1; Arabic (Syria): لونييَةB,1; Chinese (China): 栓果菊属 shuan guo ju shuC; Hebrew (Israel): לוֹנֵאָהD,1, לוניאהD,1; Italian (Italy): LauneaE,1; Vietnamese (Vietnam): Hải cúcF
1. recommended

Chromosome numbers

Diploids, more rarely tetraploids or hexaploids, x = 9, 8, 7, 6 and 5 (Kilian 1997: 80-81; Watanabe 2018).

The ancestral basic chromosome number of Launaea has been assumed by Stebbins & al. (1953: 415) to be x = 9 and can be confirmed on the basis of the much larger number of species studied today for two reasons: (1) the genus exhibits a consecutive series from x = 9 to 5; (2) the highest basic number (x = 9) is correlated with a higher caryotype symmetry, which is indicative of an original caryotype, compared with the lower numbers x = 8 and 7 (see, e.g., Mejias 1993) and particularly with the lowest number of x = 5 (L. cornuta with no metacentric chromosomes at all) (Kilian 1997: 80-81).

The members of Launaea sect. Cervicornes, Launaea, Microrhynchus and Pseudosonchus so far investigated, all show x = 9. Reduction from the ancestral basic number of x = 9 can be observed in three sections the genus: all members of L. sect. Zollikoferia so far cytologically investigated, show a basic number of x = 8; the lowest numbers x = 7, 6 and 5 are found in L. sect. Acanthosonchus and Cornutae, which are closely related with each other (Kilian 1997: 80-81).

Polyploidy has been found in Launaea sect. Launaea, Microrhynchus and Zollikoferia: in species of L. sect. Launaea (L. procumbens), in Microrhynchus (L. nudicaulis, L. petitiana) and Zollikoferia (L. fragilis), tetraploid, and in one case also hexaploid cytotypes (L. petitiana) occur beside the diploid cytotype, whereas of two species of L. sect. Microrhynchus (L. gorgadensis and L. thalassica) only the tetraploid cytotype is known (Kilian 1997: 80-81).
G,H,I,J

Bibliography

A. Nehmé, M., Dictionnaire Etymologique de la Flore du Liban. 2000
B. Nehmé, M., Etymological Dictionary of Syrian Flora. 2008
C. Wu & al., Flora of China 20-21. 2011
D. Avinoam Danin, Flora of Israel Online - http://flora.huji.ac.il
E. Pignatti, S., Flora d'Italia 3. 1982
F. Lê Kim Biên, Thục-vât-chí-Viêt-Nam / Flora of Vietnam 7. Họ cúc / Asteraceae. 2007
G. Kilian N., Revision of Launaea Cass. (Compositae, Lactuceae, Sonchinae) in Englera 17. 1997
H. Mejías J. A., Estudio cariologico del genero Launaea Cass. en la Peninsula Iberica in Lagascalia 17: 135-149. 1993
I. Stebbins G. L. & al., Chromosomes and phylogeny in the Compositae, tribe Cichorieae in Univ. Calif. Publ. Bot. 26: 401-430. 1953
J. Watanabe K., Index to chromosome numbers in Asteraceae.