ephemerals

here's another word that can do double-time:  ephemeral(s).  without the "s" it means transitory or brief, extremely temporal.  

as "ephemerals" it becomes an entire lesson in horticulture, as there are a range of plants dubbed with this moniker that have a very short life cycle or period of growth when conditions are favorable.

one example is Trillium grandiflorum, a spring ephemeral often found in deciduous forests of north america.