Hypericum undulatum

Hypericum undulatum
	Hypericum undulatum var. undulatum, collected in Europe in 1910
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Malpighiales
Family:	Hypericaceae
Genus:	Hypericum
Section:	Hypericum sect. Hypericum
Species:	H. undulatum
Binomial name
	Hypericum undulatum; Willd.

Hypericum undulatum, the wavy St Johns Wort, is a herbaceous perennial

diploid number

of 16 or 32.

Description

Hypericum undulatum grows 1.5–12 cm (0.59–4.72 in) tall, typically erect or

midrib, as well as a dense tertiary reticulation. Leaves have pale, dense laminar glands and black, close intramarginal glands that are irregular in size.^[1]

The

ovaries are 2–3.5 mm (0.079–0.138 in) long and 1–1.5 mm (0.039–0.059 in) wide. The ovoid capsules are 5–8 mm (0.20–0.31 in) long and 3.5–4 mm (0.14–0.16 in) wide. The cylindrical, yellow-brown seeds are 0.6–0.8 mm (0.024–0.031 in) long.^[1]

The plant flowers in August and September and seeds germinate in the spring.[2]

Taxonomy

Hypericum undulatum occurs in two principal varieties: H. undulatum var. undulatum and H. undulatum var. boeticum. The majority of the species, H. undulatum var. undulatum, has narrow, undulated leaf margins and reddish flower buds, but a population in Sierra Nevada has flat leaf margins and untinged leaves. This population, named H. boeticum by Pierre Edmond Boissier, has intermediate characteristics between H. undulatum and H. tetrapterum. However, the broad leaves and inflorescence resembling H. tetrapterum in H. boeticum is interpreted as parallel development between the two species; the petals and leaves of the species represent a reversion rather than an intermediate condition. The species H. boeticum is now treated as a variety of H. undulatum rather than a separate species, but certain scattered populations of true hybrids do occur in the Iberian Peninsula.^[1]

Distribution and habitat

Hypericum undulatum grows in non-calcareous fields and marshes, stream banks, fens, and acidic bogs at elevations from sea level to 2,700 m (8,900 ft). The plant prefers wet areas with lateral water movement.^[2]

Hypericum undulatum occurs in far western Europe and northern Africa. In the

Merioneth, and in Ireland it can be found in western Cork. In continental Europe it occurs in Brittany, central and western Spain, and Portugal. In Africa it occurs in western Algeria, northern Morocco, Madeira, and Azores. The variety boeticum occurs only in extreme southern Spain with the variety undulatum occurring throughout the rest of the distribution.^[1]

Ecology

Hypericum undulatum typically grows in vegetation dominated by mixtures of

Senecio aquaticus

.

Population sizes of the herb can vary greatly, increasing especially following reinstatement of grazing or burning in overgrown sites. Decline of H. undulatum in localities is mostly due to habitat loss, typically resulting from agricultural intensification. Managing populations of the herb in grasslands involves grazing in the summer and occasional burning in the winter.[2]

References

^ ^a ^b ^c ^d Robson, Norman KB (1996). "Studies in the genus Hypericum L.(Guttiferae) 6. Sections 20. Myriandra to 28. Elodes". Bulletin of the Natural History Museum, Botany Series: 78.
^ ^a ^b ^c "Hypericum undulatum". Online Atlas of the British and Irish Flora. Botanical Society of Britain and Ireland. Retrieved 10 October 2018.

[Study-1] Robson, Norman KB (1996). "Studies in the genus Hypericum L.(Guttiferae) 6. Sections 20. Myriandra to 28. Elodes". Bulletin of the Natural History Museum, Botany Series: 78.

[Online-2] "Hypericum undulatum". Online Atlas of the British and Irish Flora. Botanical Society of Britain and Ireland. Retrieved 10 October 2018.

[1]

[2]