Australian Tropical Rainforest Plants - Online edition
Pisonia aculeata L.
Linnaeus, C. von (1753) Species Plantarum 2: 1026. Type: Central America.
Una de Gato; Zarza; Thorny Pisonia; Pisonia, Thorny; Huele de Noche; Garabato
Vine stem diameters to 16 cm recorded. Short thorny branches sometimes persist on the lower stem. Blaze odour difficult to describe.
Recurved thorns 5-7 mm long, frequently produced on leafy twigs. Leaf blades about 2.5-12 x 5-5.5 cm, petioles about 0.5-3 cm long. Lateral branches subtend an angle of about 90 to the main stem. Peg-like branch stubs about 3-5 cm long are often present on older branches.
Male flowers: Flowers technically +/- sessile, peduncles resemble pedicels. Perianth about 2.5-3 mm diam. Stamens seven or eight per flower, filaments about 4-5 mm long. Female flowers: Peduncles about 15 mm long (peduncles resemble pedicels). Perianth tube about 5-7 mm long, lobes less then 1 mm long. Outer surface of the perianth tube marked by 5 longitudinal lines of green glands. Ovary about 0.7 mm long. Style about 1-1.5 mm long. Stigma fimbriate at the apex.
Fruits about 10-15 x 4 mm on a stalk about 9 mm long. Outer surface of the fruit clothed in fine longitudinal stripes of glandular projections. Fruits adhere to clothing. Seeds spindle-shaped, about 9-13 x 2.5-3 mm. Testa thin. Embryo about as long as the seed. Cotyledons bullate, about 10-12 mm long, cordate at the base, rolled into a cigar-like structure and encompassing a cylinder of endosperm or placental material. Radicle about 3 mm long.
Cotyledons unequal on each seedling, one cotyledon much larger than the other. Cotyledons ovate to broadly cordate, about 15-30 x 12-24 mm. Cotyledonary midrib raised on the upper surface. Hypocotyl hairy, the hairs multicellular, curved and reddish. First leaf blades elliptic, apex bluntly pointed, base cuneate to attenuate, underside clothed in small hairs. At the tenth leaf stage: leaf blade elliptic, apex acuminate, base cuneate to attenuate. Midrib red, raised on the upper surface. Lateral veins forming loops inside the margin of the leaf blade. All plant parts clothed in multicellular hairs, the upper surface of the leaf blade sparsely clothed. Spines up to 10 mm long, may be present in some leaf axils. Seed germination time 22 to 23 days.
Occurs in WA, NT, CYP, NEQ, CEQ and southwards as far as north-eastern New South Wales. Altitudinal range from near sea level to 750 m. Grows in monsoon forest and the drier more seasonal lowland and upland rain forests. Also occurs in the Americas, Africa, Madagascar, Mauritius, Seychelles, Ceylon, India, Burma, Indochina, Taiwan, Malesia and the Pacific islands.
This species may have medicinal properties. (http://www.earthfoot.org/mercados/herbs.html; http://squid2.laughingsquid.net/hosts/herbweb.com/ herbage/A20514.htm)