The term 'slender stalk' can be broken down into two crossword solutions: STEM (4 letters) and SPEAR (5 letters). STEM is a term used to describe the main, upright part of a plant that supports the leaves and flowers. It is usually thin and flexible, and can be found in plants such as grasses, trees, and shrubs. SPEAR is a long, pointed weapon used for thrusting or throwing. It is typically made of wood or metal and is used in hunting, fishing, and warfare.