Phanerogamae is a scientific term that refers to seed-producing plants with visible reproductive organs, and some antonyms for this term include cryptogamae, thallophytes, and bryophytes, which are non-seed plants with hidden reproductive organs. Cryptogamae is a term used to describe plants that reproduce without seeds or flowers, such as ferns, mosses, and algae. Thallophytes are plants that lack distinct stems, leaves, or roots, including fungi and lichens. Bryophytes are another type of non-seed plant, including mosses, hornworts, and liverworts.