Hypericum decaisneanum

Hypericum decaisneanum is a perennial herb that grows mostly upright and can be tall. The base of the plant can have visible roots, and its taproot is woody. It has many stems, but has no branches below its flower clusters. The flower clusters have between three and twenty flowers out of 1–4 distinct nodes. There are no flowering branches on the lower parts of the stem; all flowers are in a narrow pyramid-shaped or corymb-like cluster at the end of the stem. The bracts and bracteoles range in shape from stretched ovals to triangular lances, and have dense black glands. Individual flowers are around wide, and are an egg shape when budding. The sepals are long and , but are usually around the same size on a flower. They range in shape from narrow and oblong to wide and elliptic, with a rounded end. They have pale glands in linear patterns, and sometimes several black dots near their end. The petals are bright yellow with red veins, and measure long and wide, or roughly 2.5 times the size of the sepals. They are oblong and have a rounded tip, rather than a pointed tip or apiculus. There may or may not be scattered pale and black glands on the petals. Each flower has around 40 stamens, the longest of which are , or just shorter than the petals, and have a black anther gland. The ovary has the shape of a narrow, egg-like pyramid, with styles that are around long and curve inwards. The seed capsule is egg-shaped, and can be larger than the sepals. While the seed capsule is immature, it is enclosed by the petals which twist around each other. In general, because of its dense and hairy leaves and the black glands on its petals, the species resembles a smaller form of Hypericum annulatum subsp. afromontanum. == Etymology ==

One origin of the genus name Hypericum is that it is derived from the Greek words (above) and (picture), in reference to the tradition of hanging the plant over religious icons in the home. The specific epithet decaisneanum is in honor of French botanist Joseph Decaisne, who was a supporter of an expedition to collect the species. == Taxonomy ==

The species was originally described by Ernest Cosson and Jules Alexandre Daveau in 1899 as Hypericum decaisneanum. Cosson and Daveau placed H. decaisneanum in section Taeniocarpium based on their morphological observations. While most species of the genus Hypericum were included in a monographic study by Norman Robson in the 20th century, H. decaisneanum was not mentioned. Furthermore, its closest relatives were later addended to the monograph, and their infrageneric relationships were discussed. However, H. decaisneanum was neglected from the later editions of the monograph as well. In an online edition of the monograph published in 2013, the species was included by Norman Robson and his colleague David Pattinson within a "Huber-morathii group" inside sect. Adenosepalum. Under that classification, the placement of Hypericum decaisneanum was summarized as follows: Hypericum : 'Hypericum sect. Adenosepalum' :: '''Huber-morathii group''' ::: H. decaisneanum – H. formosissimum – H. huber-morathii – H. minutum – H. sechmenii == Distribution and habitat ==

Hypericum decaisneanum is native to the Jebel al Akhdar province of Libya. It is found in the crevices of limestone rocks at elevations of . In particular, it is found on the north-facing slopes of major escarpments. == Ecology and propagation ==

Hypericum decaisneanum belongs to plant communities that have been the subject of several research endeavors. It has been noted to be part of an association of chasmophytes that centers around Micromeria conferta and Reaumuria mucronata. It is also a part of one species association called "Athamantion dellae-cellae", and is a key species in another alliance called "Sedo micranthi-Hypericetum decaisneani" along with Sedum album and other chasmophytes. Like other species in the Huber-morathii group, H. decaisneanum can be cultivated in dry, rocky crevices with poor soil and protection against winter wetness. It can be propagated by seeding in spring under a thin layer of soil, and has a germination period of 1–3 months. Cuttings are taken in the late summer. == Notes ==