1·Most angiosperm ovules possess two integuments, while gymnosperms usually have only one.
大多数被子植物的胚珠有两层珠被，而裸子植物通常只有一层。
2·Modern gymnosperms such as ferns and gingko are typically not very nutritious and are tougher to chew than angiosperms.
现代裸子植物，诸如蕨类植物和银杏，和被子植物相比明显的非常没有营养和粗硬。