Shrubby St. John's-wort
Hypericum prolificum
Description 8
This native perennial wildflower is abundantly branched and 2-4' tall. The lower stems are woody with shredded gray-brown bark, while the upper stems are green and slightly winged on opposite sides. The opposite leaves are up to 3" and ¾" across (usually about one-half this size); they are linear-oblong to oblong-elliptic in shape, smooth along their margins, and hairless. The upper surfaces of the leaves are medium green, while their lower surfaces are pale green; they are sessile or taper to short petioles. The upper stems terminates in small clusters of 3-7 flowers; additional clusters of flowers may appear along the 2 upper pairs of opposite leaves. Each flower is ½1" across, consisting of 5 yellow petals, 5 green sepals, a pistil with 3 united styles, and abundant stamens. The petals are much larger than the sepals. The blooming period occurs during the summer and lasts about 2 months. Each flower is replaced by an ovoid-lanceoloid seed capsule about 1/31/2" in length. At the apex of each seed capsule, the tips of the 3 styles persist and become separated. Each seed capsule is divided into 3 cells and divides into 3 parts at maturity to release the seeds. The small seeds are narrowly oblongoid, flattened, and black. The root system is woody and branching.
Faunal associations 9
The flowers are cross-pollinated primarily by bumblebees, which collect pollen for their larvae. Other insect visitors that seek pollen from the flowers include Syrphid flies and Halictid bees, but they are less effective at cross-pollination. Sometimes butterflies and wasps land on the flowers, but they are vainly seeking nectar -- the flowers offer only pollen from the abundant stamens as a floral reward. Insects that feed on Shrubby St. John's Wort and other Hypericum spp. include the aphid Brachysiphum hyperici, several leaf beetles, the caterpillars of the butterfly Strymon melinus (Gray Hairstreak), and the caterpillars of several moths. The Insect Table lists many of these species. Most mammalian herbivores avoid consumption of Hypericum spp. because their foliage contains varying amounts of the phototoxic chemical, hypericin. In the presence of light, this chemical can cause rashes to develop on light-skinned animals and it can irritate the gastrointestinal tract.
Sources and Credits
- (c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/jroldenettel/7882181626/
- (c) Isa, some rights reserved (CC BY-NC), uploaded by Isa
- (c) "<a href=""http://www.knps.org"">Kentucky Native Plant Society</a>. Scanned by <a href=""http://www.omnitekinc.com/"">Omnitek Inc</a>.", some rights reserved (CC BY-NC-SA), http://plants.usda.gov/java/largeImage?imageID=hypr_001_avd.tif
- (c) "<a href=""http://www.wli.nrcs.usda.gov"">NRCS National Wetland Team, Fort Worth, TX</a>.", some rights reserved (CC BY-NC-SA), http://plants.usda.gov/java/largeImage?imageID=hypr_003_avd.tif
- 2009 Bill Moses, no known copyright restrictions (public domain), http://calphotos.berkeley.edu/cgi/img_query?seq_num=270812&one=T
- (c) Smithsonian Institution, National Museum of Natural History, Department of Botany, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=botany&irn=10457349
- (c) Smithsonian Institution, National Museum of Natural History, Department of Botany, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=botany&irn=10077088
- (c) John Hilty, some rights reserved (CC BY-NC), http://eol.org/data_objects/29442133
- (c) John Hilty, some rights reserved (CC BY-NC), http://eol.org/data_objects/29442137
