Thanks for your effort. Unfortunately, the inflorescence of Pentas lanceolata is described as "corymbs" or congested cymes. With a closer examination, you will find that they are not originated from the same point.
(References: http://herbarium.gov.hk/FloraOfHK/Species/7156/7156_S_E.pdf
http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242413973)
(References: http://herbarium.gov.hk/FloraOfHK/Species/7156/7156_S_E.pdf
http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242413973)