Cistus horrens
# Cistus horrens

Cistus horrens is a shrubby species of flowering plant in the family Cistaceae, with purple to pink flowers. It is endemic to Gran Canaria in the Canary Islands. First described as a species in 2004, it was previously identified as Cistus symphytifolius, which it resembles.

## Description

Cistus horrens generally resembles the more widespread Cistus symphytifolius. Differences include young branches covered with simple hairs; leaf blades grayer and shorter, densely covered with simple, glandular and stellate hairs on the upper surface and with longer simple hairs on the lower surface, with glandular hairs only on the nerves; sepals densely covered with simple hairs; and smaller fruiting capsules with fewer seeds. The leaves are elliptical to lanceolate, stalked (petiolate) and have netted (reticulate) veins. The stigmas are longer than the stamens.

## Taxonomy and phylogeny

Cistus horrens was first described as a new species by Jean-Pierre Demoly in 2004; it had previously been treated as C. symphytifolius. The specific epithet horrens is Latin for "standing erect, bristling".

A 2011 molecular phylogenetic study placed C. horrens as a member of the purple and pink flowered clade (PPC) of Cistus species, along with some other Canary Island endemics (Cistus asper, Cistus chinamadensis, Cistus ocreatus, and Cistus symphytifolius).

Species-level cladogram of Cistus species. :

| Halimium spp.    PPC     Cistus crispus       Cistus asper   Cistus chinamadensis   Cistus horrens   Cistus ocreatus   Cistus osbeckiifolius   Cistus palmensis   Cistus symphytifolius     Cistus heterophyllus     Cistus albidus   Cistus creticus   Halimium spp.   WWPC       Cistus clusii   Cistus munbyi     Cistus inflatus   Cistus ladanifer   Cistus laurifolius   Cistus libanotis   Cistus monspeliensis   Cistus parviflorus   Cistus populifolius   Cistus pouzolzii   Cistus salviifolius   Cistus sintenisii | Purple Pink Clade  White Whitish Pink Clade |
| - | - |

Species-level cladogram of Cistus species, based on plastid and nuclear DNA sequences. :

## Distribution and habitat

Cistus horrens is endemic to Gran Canaria in the Canary Islands, being found in the south-west sector of the island. It is typically found at elevations of 300–1,500 metres (1,000–4,900 ft) in pine forests, in semiarid conditions.

