Electronic Flora of South Australia
Electronic Flora of South Australia
Census of SA Plants, Algae & Fungi
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Electronic Flora of South Australia genus Fact Sheet

Family: Rhamnaceae

Citation: Labill., Nov. Holl. Pl. Sp. 1:61 (1805).

Derivation: Greek psma, a lid; derris, a skin; alluding to the membranous valve by which the fruitlets of many species open.

Synonymy: Not Applicable

Common name: None

Shrubs with a tomentum of stellate hairs usually intermixed with longer simple hairs; leaves alternate, petiolate, flat or almost so, pinnately nerved, green above, whitish or rusty below.

Flowers small, pedicellate in small umbel-like cymes forming racemes or panicles, bisexual, stellate-tomentose; buds globular; bracts caducous; sepals 5 rarely 4, spreading or finally reflexed and caducous; petals often absent, never enclosing the anthers; stamens 5 rarely 4, with rather long (longer than the anthers) filaments which are inflexed behind the anthers; floral tube hollow, not extended upwards beyond the adnate part of the ovary; ovary almost wholly inferior, 3-celled, rarely 2-celled, the summit usually hairy; disk obscure or 0; style usually 3-branched, the branches clavate.

Capsule small, with a thin exocarp protruding and convex above the floral tube so that the whole fruit is pyriform, the protruding summit opening in 3 deltoid valves, the endocarp separating into 3 coriaceous 1-seeded fruitlets which open on the inner face often by a small door-like valve extending upwards from the base; seeds ovoid, dorsally compressed, with a crustaceous testa; funicle dilated into a cup-shaped aril at the base of the seed.

Distribution:  About 40 species, all but 2 Australian, 5 species occurring in New Zealand. Pomaderris.

Biology: No text

Taxonomic notes: There are three species whose occurrence in S.Aust., although reported, is improbable: P. aspera Sieber ex DC., Prod. 2:33 (1825). (Rough) hazel pomaderris. (Ill. Costermans (1981) Native trees and shrubs of south-eastern Australia, p. 217.). Leaves usually 5-6 (but up to 10) cm long; flowers in panicles; sepals 1.5-2 mm long. --P. apetala sensu J. Black, Fl.S. Aust. 546 (1952), non Labill. This species was collected "near Gladstone" by an unknown collector (J. Black (1952) knew it from two specimens from this locality but only one is preserved in AD). This locality is some 550 km from any other locality for this species and, as it has not been recollected in S.Aust. and as there are several towns of the same name elsewhere in Australia, it is considered unlikely to be native to or naturalised in S.Aust. P. myrtilloides Fenzl in Endl., Enum. Pl.Hügel 22 (1837). The only species reported for S.Aust. with narrow-linear petals; calyx silky. Recorded last century from KI and GT, but there is no specimen in AD and its occurrence is thought to be improbable. P. vacciniifolia Reisseck in F. Muell., Linnaea 29:266 (1858). Round-leaved pomaderris. Petals broad; calyx hoary. Twice reported in the 1890s from SL. There is no specimen in AD and the nearest known localities are east of Melbourne. A plant of cultivated origin from the SE has been tentatively identified as belonging to this species. A specimen under this name in the Schomburgk Herbarium of unknown origin has been reidentified as P. forrestiana.

Key to Species:
1. The longest leaves on a branch at least 30 mm long
P. halmaturina 3.
1. Leaves up to 25 mm long
2. Petals present
P. forrestiana 2.
2. Petals absent
3. Leaves 2-lobed or obcordate (some leaves sometimes truncate-dentate at the apex)
P. obcordata 4.
3. Leaves more or less flabellate or oblong to ovate or orbicular but not lobed or obcordate
4. Leaves flabellate or laterally elliptic, usually broader than long, to 8 mm long (central and southern EP)
P. flabellaris 1.
4. Leaves oblong to ovate or orbicular, rarely as broad as long, the longest on each branch rarely less than 8 mm long (widespread)
P. oraria 5.

Author: Prepared by J.P. Jessop

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