achillea aesculus hippocastanum alnus incana angiosperm phylogeny website araceae aristolochia clematitis arum maculatum asteraceae boraginaceae bract branch caryophyllaceae catkin commelinaceae cyathium cyme dipsacaceae dipsacus fullonum echinops ritro euphorbia ficus flower fruit gentiana lutea hedera helix internode iridaceae lamiaceae leaf lilium martagon lolium temulentum melilotus officinalis mentha longifolia monopodial moraceae oryza sativa panicle phyllotaxis plant stem plantago media poaceae raceme rhinanthus angustifolius sambucus nigra shoot silene dioica spadix spike symphytum officinale sympodial syringa vulgaris tilia cordata umbel vitis vinifera wikimedia commons wisteria sinensis