From Common Forest Trees of Hawaii

Pleroma urvilleanum
Meadowbeauty family (Melastomataceae)

Post-Cook introduction

This introduced ornamental has escaped from gardens and become naturalized as a weed, forming impenetrable thickets. It has large showy flowers 3–4 inches (7.5–10 ) across the five spreading violet or purple petals. Distinguished also by the paired elliptical, velvety hairy leaves with five main veins from base.

©2004 Forest And Kim Starr
A tall shrub commonly 15 ft (4.6 ) high or becoming a small tree to 40 ft (12 ) high and 4 inches (10 ) in trunk diameter, with few slender erect branches. Bark light gray, smoothish, thin. Twigs four-angled and slightly winged, stout, light green, with long greenish or pinkish spreading hairs, ringed at older twigs shedding hairy bark and becoming round.

Leaves elliptical, with very hairy leafstalk 1⁄4– 3⁄4 inch (6–19 ) long. Blades elliptical, 2 1⁄4–5 inches (3–13 ) long and 1–2 1⁄2 inches (2.5–6 ) wide, long-pointed at blunt or rounded at base, edges straight, with five (sometimes seven) main veins from base; these and curved smaller veins sunken on upper surface and raised beneath. Upper surface yellow green, covered with pressed hairs; lower surface silvery or light green, velvety hairy. Dying leaves turning red above, silvery orange beneath.

Flower clusters () erect, large, branched, 3–5 inches (7.5–13 ) long. Flowers several but not opening together, very large and showy, on short hairy stalks, composed of 2 large hairy pointed pinkish or 1 inch (2.5 ) long and rose-red buds; densely hairy with narrow tube 5⁄8 inch (1.5 ) long, five narrow spreading hairy, reddish-tinged almost as long, shedding; five violet or purple petals about 1 1⁄2 inches (4 ) long and nearly as broad, oblong, broad and straight at widely spreading and falling early; 10 long threadlike purple of two sizes, bent in middle, with narrow curved and with hairy five-celled many tiny ovules, and long threadlike curved purple

is an egg-shaped pale brownish 5⁄16 inch (8 ) long, five-celled, with many small round seeds.

The wood is reddish brown, hard, strong, and difficult to cut. Not used.

This species has become naturalized and is classed as a weed in pastures and wastelands. It forms dense thickets by spreading vegetatively from roots, and cut branches also bear roots and grow.

Scattered, forming impenetrable tangles in moist open forests and roadsides at 1500–4000 ft (457–1219 ) altitude, especially in the Volcano area of the island of Hawaii.

Special areas
Wahiawa, Volcanoes

Naturalized through the Hawaiian Islands from Kauai and Oahu to Hawaii. Native of Brazil (Rio de Janeiro and Rio Grande do Sul) and widely cultivated as an ornamental.

Other common names
Urville glorybush, Hawaiian glorybush, tibuchina, lasiandra

Tibouchina urvilleana (DC.) Cogn., Lasiandra urvilleana DC., Formerly identified as Tibouchina semidecandra Cogn., a related species also of Brazil.

Degener (1930) stated that it was introduced in about 1910 from South America, traced to an estate near Kurtistown, Hawaii. The first herbarium specimen was collected by Rock in August 1917 at Kalanilehua, Kilauea, Hawaii. It was spread by amateur horticulturists who took cuttings to their gardens. By 1930 this weed was observed in a garden near Honolulu. At that time Degener predicted the spread and also the replacement of native vegetation, which has since occurred. As he observed in 1970, this species exemplifies the difficulty of eradicating ornamentals cultivated in the islands that become weeds.

Two additional shrubby naturalized species in this family have become weeds. Koster’s curse, Clidemia hirta (L.) D. Don, has small white flowers and small blackish or purplish edible berries. Melastoma candidum D. Don ( melabathricum auth., not L.) has large pink to purple flowers and small bristly berrylike They are of no forage value and may be found in wastelands, pastures, and lowland forests.

node -- The point at which there is attached growth, as in the place where each leaf is attached.

cm -- A centimeter which is about 0.4 inches.

m -- A meter is about 10% larger than a yard.

style -- This is a long and thread-like structure that connects the stigma with the ovary. A flower may have a single style, or several of them.

scale -- A very small leaf around a dormant bud. Also other things that might remind one of fish scales on the surface of ferns, stems and the like.

A noxious weed is considered to be harmful to the environment or animals. Often a governing body designates plants as noxious.

Bracts are modified leaves associated with a flower.

terminal -- Located at the end (the tip or the apex).

The anther is a pad at the end of the stamen that holds the pollen.

A panicle is a much-branched inflorescence. The bottom flowers in a panicle open first.

A pistil is the female structure of many flowers. It contains one or more carpels. Each carpel contins an ovary, style and stigma. The stigma receives the pollen which grows thru the style to reach the ovary.

An evergreen tree retains a large portion of its green leaves all year.

In an opposite leaf arrangement the leaves come in pairs with one leaf on each side of a stem.

lobe -- Rounded parts of a leaf (or other organ). Lobes bulge out about 1/4 of the leaf diameter.

capsule -- a type of simple, dry fruit produced by many species of flowering plants. In most cases the capsule splits apart to release seeds.

fruit -- any seed-bearing structure in flowering plants. It is formed from the ovary after flowering.

synonym -- In botany a synonym is a species name that at one time was thought to be the correct name for a plant but was later found to be incorrect and has been replaced by a new name.

mm -- millimeter. About 1/25th of an inch.

calyx -- the sepals of a flower, typically forming a whorl that encloses the petals and forms a protective layer around a flower in bud.

The apex is the tip or the furthest point from the attachment.

stamen -- the pollen-producing reproductive organ of a flower; The stamen consists of an anther supported by a filament.

An ovary is a part of the female reproductive organ of the flower. Above the ovary is the style and the stigma, which is where the pollen lands and germinates to grow down through the style to the ovary.