Once they conquered the land, the earliest land plants (the bryophytes) were like the amphibians: they can live on dry land, but they need water for mating. The seed plants acquired a kind of internal fertilization, because they use pollen grains to deliver their sperms right to the stigma or the ovule, where a pollen tube can take it the last few millimetres to the egg. In this, the seed plants resemble the mammals. However, this is an analogy. These plants are doing similar things to the animals for similar reasons, but in completely different ways.