Conifers (gymnosperms) differ from grasses (angiosperms) because in gymnosperms, the female gametophyte is actually endosperm, which is made before fertilization. However, in grasses, endosperm is a tissue formed by the fertilization of the second male gamete to polar nuclei. Moreover, in gymnosperms, the endosperm is a haploid tissue, whereas in angiosperms it is triploid.