Here is a curious bulb (or rather tuber) which I haven't planted before: Corydalis cava. Shipton Bulbs describe it as "this old introduction from Europe. It has long been naturalised in woods and hedges where it forms clumps of tubular pink flowers in March with attractive divided foliage".

 Sometimes known as Hollowroot. I wondered why and turning this one over it does indeed look like a section of hollowed out root...