Silicon (Si) is becoming increasingly recognized as a beneficial element; for rice and other crop plant species, Si has been shown to enhance mechanical support, photosynthetic water use efficiency, and resistance to pathogens, and/or ameliorate heavy metal toxicity. Despite being the second most abundant element in earth’s crust, soil Si availability declines with chemical weathering, the rate of which is faster under humid and warm tropical conditions. From studies of mostly temperate plant species, it is recognized that phylogenetic groups of plants differ greatly in the extent of their Si uptake and accumulation. But, published data are scant on silicon accumulation patterns for tropical wild plants. Here, I summarize published and unpublished data of silicon accumulation by terrestrial plants to demonstrate (1) strong phylogenetic signals in Si accumulation by pants, (2) latitudinal and longitudinal patterns suggesting selective pressures favoring Si use by plants in the lowland tropical forests compared to higher latitudes and longitudes, and (3) significant influence of biogenic Si cycles on soil weathering and other soil-mediated ecosystem processes in tropical forests.