An unexpected discovery is always welcome. In a waste field, about a mile from Royston, I once found a tall branching plant with an abundance of yellow cruciferous flowers, which I should not have recognized but for the fact that a year or two previously my friend Edward Carpenter had sent me a specimen from Corsica. It was the woad, famous as the source of the blue dye with which the ancient Britons stained themselves. A mere "casual" in Hertfordshire, it is said to be established in a few chalk-quarries near Guildford and elsewhere. Thus far I have spoken of none but field flowers; but the district does not consist wholly of cultivated land, for even in that wilderness of tillage there are oases which have never felt the plough, and where the flora is of a different order. Therfield Heath, near Royston, is one of them, a grassy slope where the handsome purple milk-vetch is plentiful, and one may find, though in less abundance, the sprightly field fleawort, which seems more familiar as an ornament of the high chalk Downs. Nor are water springs wanting in the bare ploughlands. The little river Ivel, which leaps suddenly to light near Baldock, and thence races northward to join the Bedfordshire Ouse, is a clear trout-stream by whose banks it is pleasant (whatever the trespass notices may threaten) to wander, and to watch the quick-glancing fish. At the hamlet of Radwell, in a moist copse, there is a patch of the rare monk's-hood, a poisonous flower of which later mention will be made. A joint tributary of the Ouse, and not less inviting, is the oddly named Hiz, which has its source on Oughton Common, a boggy flat near Hitchin, where both the butterwort and the grass of Parnassus are recorded as having grown and may perchance be growing still: as for the marsh orchis, one cannot cross the Common without seeing it. Then at Ickleford, a village on the banks of the Hiz, there is a pond which has been "occupied" (to use a military term) by the water-soldier, a stout aquatic which takes its name from the rigid swordlike leaves enclosing the three-petaled flowers. Peculiar to the eastern counties, this water-soldier is said to have been introduced at Ickleford over half a century ago; and there it now makes a fine array, having thriven wonderfully in spite of the worn-out pots and pans, and other refuse, for which, in Hertfordshire as elsewhere, the nearest pool or stream is thought a fit receptacle.