Convolvulaceae (incl. Cuscutaceae)
Recent molecular research strongly supports inclusion of Cuscutaceae in Convolvulaceae (see for instance Neyland 2001, APG III 2009).
A virtual herbarium of Convolvulaceae (by D. Austin) is available at: http://www.virtualherbarium.org/vh/Convolvs/default.htm.
1. Plant a twining parasite without chlorophyl. Stem orange, yellowish, reddish or greenish white, never green. Inflorescence a globose, sessile head === Cuscuta
1. Plant often twining but never parasitic, always with chlorophyl. Stem green. Inflorescence of solitary or few flowers in leaf axils === 2
2. Corolla inconspicuous, up to 5 mm long, greenish white, divided for at least half its length. Stems creeping === Dichondra
2. Corolla conspicuous, much longer, variously coloured but never greenish white, not divided. Stems twining, sometimes creeping === 3
3. Bracteoles ovate, at least partly obscuring sepals === Convolvulus p.p. (“Calystegia”)
3. Bracteoles lanceolate to filiform, not obscuring sepals === 4
4. Stigma with 2 filiform lobes === Convolvulus p.p. (“Convolvulus s.str.”)
4. Stigma with 2 or 3 globose lobes or (almost) globular === Ipomoea
APG III (2009) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. APG III. Bot. J. Linn. Soc. 161(2): 105-121.
Neyland R. (2001) A phylogeny inferred from large ribosomal subunit (26S) rDNA sequences suggests that Cuscuta is a derived member of Convolvulaceae. Brittonia 53(1): 108-115.