Cyperus alternifolius, or schefflera, or "Umbrella" tree is a fast grower if you get it's sunlighth and watering needs met sufficiently.  It can get at least 6 feet high and it does look very tree like with sparse leaves on bottom and most sprouting at the top so it becomes top heavy as it gets bigger, meaning you will want a heavier pot when full grown so it doesn't tip over!  It's tall, oval leaves havve eight spokes typically, hence the name umbrella.  Overall it can tower over your other plants and bring some needed height to a collection or on it's own in a corner.  Definetely a favorite here! 

  Bright but indirect sunlight.  

  Water infrequently when the top couple inches of soil are dry.  It does like humidity but does not like being wet!  In other words, don't make it rain on this Umbrella