fastigiate

adjective

1. rising to a pointed top.
2. Zoology. joined together in a tapering adhering group.
3. Botany.
   1. erect and parallel, as branches.
   2. having such branches.

adjective biology

1. (of plants) having erect branches, often appearing to form a single column with the stem
2. (of parts or organs) united in a tapering group