Ludwigia sect. Jussiaea

(Linnaeus) Baillon

Hist. Pl. 6: 463. 1876.

Basionym: Jussiaea Linnaeus Sp. Pl. 1: 388. 1753
Synonyms: Gen. Adenola Rafinesque Cubospermum Loureiro Jussiaea sect. Oligospermum Micheli Ludwigia sect. Oligospermum (Micheli) H. Hara Ludwigia sect. Oocarpon (Micheli) P. H. Raven Oocarpon Micheli
Treatment appears in FNA Volume 10.

Herbs, perennial, subshrubs, or emergent aquatics, creeping, floating, or emergent and ascend­ing, rooting at nodes, when floating often forming spongy, white pneumatophores at nodes, when erect with spongy base. Stems decumbent to erect or ascending, terete, sometimes angled distally. Leaves alternate or fascicled. Flowers 5 (or 6) -merous; petals present, yellow [white]; stamens 2 times as many as sepals, [rarely as many as]; pollen shed as monads. Capsules cylindric, subcylindric, or subclavate, terete, subterete, or obscurely angled, often upcurved, with thick, woody walls, irregularly and tardily dehiscent. Seeds in 1 row per locule, pendulous and firmly embedded in woody, coherent segment of endocarp, raphe inconspicuous. 2n = 16, 32, 48, 80, 96.

Distribution

United States, Mexico, West Indies, Central America, South America, s Asia, Africa, in Europe, Pacific Islands, Australia

Discussion

Species 9 (3 in the flora).

This cosmopolitan polyploid section of nine variable species (11 taxa) includes three diploid species (n = 8), four tetraploids (n = 16), one hexaploid [Ludwigia grandiflora, n = 24; P. H. Raven and W. Tai (1979) reported one anomalous count of n = 48], and one decaploid (L. hexapetala, n = 40; see also G. L. Nesom and J. T. Kartesz 2000). One persistent triploid (2n = 24) hybrid, described as L. ×taiwanensis C. I. Peng [L. adscendens (n = 16) × L. peploides subsp. stipulacea (n = 8); Peng 1990] is widespread in southern China and Taiwan. E. Zardini et al. (1991) reported several other natural hybrids.

Most species of sect. Jussiaea have non-naturalized distributions restricted to the New World. Section Jussiaea differs from most diplostemonous sections by releasing its pollen as monads and having woody, subcylindric capsules with uniseriate, firmly embedded seeds. Most species in sect. Jussiaea are vigorously aquatic, and several (including L. peploides, L. hexapetala, and L. grandiflora) can be invasive weeds in wetlands and wet agricultural areas; the latter two, or all three, species have recently become major invasive species in California, particularly in the Russian and Sacramento river drainages and in the San Diego region, in Arizona (especially Gila and Salt rivers), and in Washington (M. Wood 2006; P. C. Hoch and B. J. Grewell 2012).

Selected References

None.

... more about "Ludwigia sect. Jussiaea"
96 +, 80 +, 48 +, 32 +  and 16 +
3(-5)-aperturate +
valvelike +, conical +  and flat +
Peter C. Hoch +
(Linnaeus) Baillon +
Jussiaea +
indehiscent +  and loculicidal +
lobed +, toothed +  and entire +
deltate +, usually linear +  and lanceolate oblong or obovate +
reduced +
dark red +  and black +
straight +  and slightly curved +
angled +, subterete +, terete +, subclavate +, subcylindric +  and cylindric +
United States +, Mexico +, West Indies +, Central America +, South America +, s Asia +, Africa +, in Europe +, Pacific Islands +  and Australia +
basifixed +  and versatile +
long-pedicellate +  and subsessile +
straight +  and slightly curved +
by a terminal pore +  and dehiscent +
spreading +  and erect +
cylindric +  and clavate turbinate obpyramidal or globose +
perennial +
glandular-puberulent +, hirtellous +, villous +  and strigillose +
fascicled +  and alternate +
deciduous +
entire +, glandular-serrulate +  and serrulate +
numerous +  and 1 +
submerged +
swollen +
5 +  and 4 +
paired +, solitary +  and cluster +
ascending +, decumbent +  and erect +
inconspicuous +
expanded +
basal +  and cauline +
clavate +  and globose +
50 +  and 400 +
pitted +  and smooth +
flushed with red +, cream +  and yellow +
persistent +
post-anthesis +
spreading +  and suberect +
5 +  and 4 +
parenchymatous +
parietal +, axile +  and placentation +
2 +  and 1 +
unequal +  and subequal +
2 times as many as sepals +
aquatic +, amphibious +  and terrestrial +
2 times as many as sepals +
prostrate +  and decumbent +
decumbent +  and erect or ascending +
angled +  and terete +
hemispherical +, capitate +, lobed +  and entire +
sessile +  and petiolate +
green +  and dark reddish +
intrapetiolar +
aquatic +, amphibious +  and terrestrial +
emergent +  and floating +
papillate +
Gen. +, Adenola +, Cubospermum +, Jussiaea sect. Oligospermum +, Ludwigia sect. Oligospermum +, Ludwigia sect. Oocarpon +  and Oocarpon +
Ludwigia sect. Jussiaea +
Ludwigia +
section +
3(-5)-aperturate +