Zornia dyctiocarpa



Zornia dyptiocarpa var. dyptiocarpa

DC. 1825

pronounced: ZOR-nee-uh dik-tee-oh-KAR-puh

(Fabaceae — the pea family)

subfamily: Faboideae - the bean subfamily

synonym — Zornia diphylla

(L.) Pers. 1806

pronounced: ZOR-nee-uh diff-ILL-uh

common name: zornia

native 4Zornia is named for Dr Johannes Zorn (1739-1799), a German pharmacist; dyctiocarpa is from the Greek, δυικος (dyïkos), dual, and καρπος (karpos), fruit. In the synonym, diphylla is from the prefix δι- (di-) double, and φυλλος (phyllon), a leaf. The difference between this variety and the other variety of the species, var. filifolia, is that the latter has leaves 1 – 2.5 mm wide, with bracts 1 – 2 mm wide, while var. dyctocarpa has leaves that are mostly 3 – 7.5 mm wide, and bracts 2.5 – 5 mm wide. Authorities are not in agreement as to which of the two names should be the accepted one.

The distribution of the plant is almost worldwide in warmer areas. In Australia it is mostly found right down the eastern coastal strip, with a few isolated colonies in the Northern Territory and the ACT. It is a plant of open forests, especially eucalypt woodlands, and grasslands. The plants photographed were in the Butler Creek area of Picnic Bay.

This is a perennial herb with prostrate or weakly ascending stems to about 50 cm long. The stems are glabrous,or rarely sparsely hairy. The stipules are 7 – 12 mm long, 1 – 3 mm wide, glabrous, not gland-dotted, 3 – 6-nerved, not very persistent. Petioles are 7 – 20 mm long. The leaves are compound, with two leaflets, and are alternate along the stem. The leaflets of the upper leaves are 15 – 30 mm long, glabrous or very sparsely hairy, sometimes sparsely gland-dotted, the margins usually more-or-less parallel, the tip narrowly pointed, those of the lower leaves lesser and broader.

The inflorescence, consiisting of typical pea flowers, is usually a much-interrupted spike 6 – 17 cm long, including the 2 – 7 cm peduncle. Flowers are borne between pairs of bracts well-separated along the rachis, the margins of the bracts fringed with hairs. The corolla is 6 – 11 mm long, yellow, the veins on the front of the standard often reddish purple towards the base. Flowering is from summer to autumn.

The seed pods have 5 – 7 articles, breaking up at maturity. The articles are 1.5 – 2 mm long and wide, reticulately veined, hairless or sparsely and minutely hairy, with few to many barbed bristles, or sometimes none.

The plant nodulates, but is not productive, and it is of no grazing significance.

Another species in the genus, Zornia pallida, has similar leaflets, but markedly overlapping floral bracts and larger articles. It is found only between Rockhampton and Gayndah.


Photographed by Butler's Creek, Picnic Bay, April 2019
Page last updated 28th April 2019