# Hypericum iwatelittorale

Hypericum iwatelittorale, originally styled Hypericum iwate-littorale, is a species of flowering plant in the family Hypericaceae. Named for its habitat in the coastal regions of the Iwate Prefecture in Japan, little is known about the ecology and conservation status of the plant. The species is a small perennial herb with five bright yellow petals on its up to thirty flowers. It has many stamens, and an array of pale and black glands on its leaves, sepals, and petals. Described in 1937 by Hideo Koidzumi, it has at times been considered a synonym of Hypericum pseudopetiolatum. However, it was affirmed to be a valid species in 2003 and was placed into the type section of Hypericum, with its similarities to H. tosaense being noted.

## Description

Hypericum iwatelittorale is a perennial herb that grows upright to a height of 25–32 centimetres (9.8–12.6 inches). The leaves on its lateral branches have petiolules, or leaflet stalks, which have a shape between that of an ellipse and a blunted lance. The flowers are 0.9–1.0 cm (0.35–0.39 in) wide. The sepals are 0.3–0.4 cm (0.12–0.16 in) long and are pointed, with few or no glands on their edges.
The stems grow alone or in small groups, and have branches on their upper parts. They have two visible lines that run laterally and have black point-shaped glands. The internodes, or length of stem between leaf nodes, are usually longer than the leaves themselves. The leaves are directly attached to the main stem, or have a short leaf stalk when attached to the lateral branches. The leaf blade is 1.2–1.4 cm (0.47–0.55 in) long by 0.5–0.8 cm (0.20–0.31 in) wide, and is an oval to stretched-ellipse shape. The blades are a paler color on the undersides and have a papery texture. The leaf tip is rounded, the edges are smooth, and the base is blunt to rounded. There are dense, pale, point-shaped glands on the surface of the leaves, and black or reddish glands around the edges.
Each inflorescence, or flower cluster, has up to thirty flowers from as many as three primary nodes and four lower nodes. The cluster is in the shape of a corymb, with short pedicels and small bracts that are lance-shaped. The flowers are 0.9–1.0 cm (0.35–0.39 in) wide and may be star-shaped. There are five sepals of roughly the same size: 0.3–0.4 cm (0.12–0.16 in) long and 0.1–0.2 cm (0.039–0.079 in) wide. They are pointed and lance-shaped, with pale glands on their surface and few or no black glands on their edges. Each flower has five bright yellow petals that are 0.6–0.9 cm (0.24–0.35 in) long and have pale glands on their surface and very few black glands on their edges. There are around fifty stamens per flower, the longest of which is roughly 0.7 cm (0.28 in) long. The seed capsule is roughly oval-shaped, with oil valves that run longitudinally. The seeds are dark brown, 0.12 cm (0.047 in) long, and cylindric in shape.

## Etymology

Subsection Hypericum
Series Hypericum
H. scouleri
H. momoseanum
H. yezoense
H. attenuatum
H. iwatelittorale
H. tosaense
H. perforatum
H. maculatum
H. tetrapterum
H. triquetrifolium
H. undulatum
Series Senanensia :
Cladogram showing the relationships between species of series Hypericum :
One origin of the genus name Hypericum is that it is derived from the Greek words hyper (above) and eikon (picture), in reference to the tradition of hanging the plant over religious icons in the home. The specific epithet is made up of the combination of iwate, for the species' habitat in the Iwate Prefecture, and littorale, which derives from the Latin word litoralis and means "littoral" or "coastal". Its Japanese name is シオカゼオトギリwhich can be transliterated as shio kaze otogiri.

## Taxonomy

The species was first collected in 1934 by Hideo Koidzumi, a Japanese botanist, and was originally described as Hypericum iwate-littorale in the Journal of Plants of Iwateken in 1937. Arika Kimura later doubted the validity of the species, and placed it as a synonym of Hypericum pseudopetiolatum in subsection Erecta. In 2003, as a part of his monograph of the genus Hypericum, Norman Robson restored it to the status of valid species and placed it in series Hypericum because of its raised stem lines with gland dots. He also standardized the name as Hypericum iwatelittorale. Robson noted the plant's similarities to Hypericum tosaense, but decided that minor differences in appearance and wide separation geographically warranted its inclusion as a separate species. It is also closely related to H. momoseanum and H. yezoense.

## Distribution, habitat, and conservation

Hypericum iwatelittorale is found in temperate coastal regions of the Iwate Prefecture in Honshu, Japan.
The conservation status of H. iwatelittorale is unknown. It was first surveyed by the Japanese government in 2012, and is considered data deficient by the Global Red List of Japanese Threatened Plants. The local Iwate Red Data Book evaluated threats to the species caused by the 2011 Tōhoku earthquake, and concluded that habitat loss due to natural disasters or road construction were the greatest risks.