Harmsiopanax ingens of the Gensing, or Ivy Family (Araliaceae), is a very spiney palmlike mesocaul tree endemic to the montane rainforests of central New Guinea which bears a terminal rosette of deeply lobed, meter-wide (3.25-foot wide) dentate margined, peltate leaves (Sometimes not peltate), maple-like in shape, on equally long petioles.

It ultimately attains a height of eighteen meters (59 feet), at which point it bears a huge panicle of flowers five meters (16.5 feet) high and equally wide; the largest above ground inflorescence of any dicot plant[1] (although Caloncoba flagelliflora (Achariaceae; of West Africa)[2] and Ficus geocarpa (Moraceae; of the Malay Peninsula)[3] and Ficus unciata var.

strigosa (also of Malaya)[4] have larger subsurface panicles, each about nine meters (thirty feet) in length.

So panicle, spike and umbel are all represented in a single inflorescence.

[5] Harmsiopanax ingens is monocarpic, and again the largest such plant among dicots.