Belongs within: Convolvulaceae.
The Cresseae are a group of convolvulaceous plants with two or bifid styles in each flower and fruits a dehiscent capsule.
Characters (from Stefanović et al. 2003): Plants suffrutescent herbs to shrubs, less often lianas. Leaf base not cordate. Flowers actinomorphic, usually bisexual (unisexual in Hildebrandtia). Sepals equal or unequal, usually non-accrescent (accrescent in Hildebrandtia female flowers and some Seddera spp.) Styles two or bifid. Stigmas globose, reniform, or lobed. Filaments usually straight, glabrous. Fruit dehiscent, capsular (rarely utricular), 1–4 locular, 1–4-seeded. Pollen 3-colpate or pantocolpate, non-echinate.
Cresseae [Evolvuleae, Neuropeltidae, Neuropeltideae, Wilsonieae, Wilsoniinae, Wilsonioideae]SAO03
|--Hildebrandtia [incl. Cladostigma, Sabaudiella; Hildebrandieae, Hildebrandtieae]SAO03
|--Seddera latifoliaSAO03, PP07
|--StylismaSAO03
|--Itzaea sericeaSAO03
|--Neuropeltis racemosaSAO03
|--NeuropeltopsisSAO03
|--CressaSAO03
| |--C. australisLK14
| |--C. creteicaSAO03
| `--C. truxillensis [incl. C. truxillensis var. vallicola]H93
|--Wilsonia Br. 1810SAO03, KC01
| |--W. backhouseiBR65
| |--W. humilisSAO03
| `--W. rotundifoliaBR65
|--BonamiaSAO03
| |--B. mediaLK14
| |--B. pannosaLK14
| |--B. roseaK90
| |--B. semidigynaST98
| `--B. spectabilisST98
`--Evolvulus L. 1762L95
|--E. alsinoides Linnaeus 1762 [incl. E. linifolius]BR65
| |--E. a. var. alsinoidesLK14
| |--E. a. var. debilis (HBK.) Ooststr. 1934 [=E. debilis HBK. 1918]L95
| |--E. a. var. decumbensLK14
| |--E. a. var. grisebachianus Meissn. in Martius 1869L95
| `--E. a. var. villosicalyxLK14
|--E. argyreusST98
|--E. convolvuloides (Willd. ex Schultes) Stearn 1972 (see below for synonymy)L95
|--E. glomeratusOB08
|--E. nummularius (L.) L. 1762 [=Convolvulus nummularius L. 1753]L95
`--E. sericeus Sw. 1788L95
Evolvulus convolvuloides (Willd. ex Schultes) Stearn 1972 [=Nama convolvuloides Willd. ex Schultes 1820; incl. E. glaber Spreng. 1824]L95
*Type species of generic name indicated
References
[BR65] Black, J. M., & E. L. Robertson. 1965. Flora of South Australia. Part IV. Oleaceae–Compositae. W. L. Hawes, Government Printer: Adelaide.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[K90] Keighery, G. J. 1990. Vegetation and flora of Shark Bay, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 61–87. Western Australian Museum.
[KC01] Kirk, P. M., P. F. Cannon, J. C. David & J. A. Stalpers. 2001. Ainsworth & Bisby’s Dictionary of the Fungi 9th ed. CAB International: Wallingford (UK).
[L95] Liogier, H. A. 1995. Descriptive Flora of Puerto Rico and Adjacent Islands: Spermatophyta-Dicotyledoneae vol. 4. Melastomataceae to Lentibulariaceae. Editorial de la Universidad de Puerto Rico.
[LK14] Lyons, M. N., G. J. Keighery, L. A. Gibson & T. Handasyde. 2014. Flora and vegetation communities of selected islands off the Kimberley coast of Western Australia. Records of the Western Australian Museum Supplement 81: 205–244.
[OB08] Olmstead, R. G., L. Bohs, H. A. Migid, E. Santiago-Valentin, V. F. Garcia & S. M. Collier. 2008. A molecular phylogeny of the Solanaceae. Taxon 57 (4): 1159–1181.
[PP07] Pandey, R. P., & P. M. Padhye. 2007. Studies on phytodiversity of Arid Machia Safari Park-Kailana in Jodhpur (Rajasthan). Bulletin of the Botanical Survey of India 49: 15–78.
[ST98] Schimming, T., B. Tofern, P. Mann, A. Richter, K. Jenett-Siems, B. Dräger, N. Asano, M. P. Gupta, M. D. Correa & E. Eich. 1998. Distribution and taxonomic significance of calystegines in the Convolvulaceae. Phytochemistry 49: 1989–1995.
[SAO03] Stefanović, S., D. F. Austin & R. G. Olmstead. 2003. Classification of Covolvulaceae: a phylogenetic approach. Systematic Botany 28 (4): 791–806.