其中一种的“眼”中，有一个小小的绿球，像大头针的头一样，英语是pin–eyed，直译是“大头针花心”，汉语叫“长花柱花”。另一种花心，边上有一圈小小的黄色花药，这种花英语叫做thrum-eyed，直译是“线头花心”，汉语叫“短花柱花”。

　　Let us split open the tube of one of each kind. Both have the broad green seed-vessel down at the bottom of the tube, and from it there rises a slender green thread with a round sticky knob at the top. This thread is called the style. Now you see that in one of the flowers the style rises to the top of the tube, and in the other it rises only half-way.

　　咱们把两种花心的“花冠筒”各掰开一条。两种花冠筒底部，都有宽宽的绿色“子房”，从它里面长出一根细丝，顶端有一个带着粘性的小圆球。这细丝叫做“花柱”，现在你看到了，在一朵花当中，花柱会长到花冠筒顶端，在其他花当中，却只长到花冠筒的一半高。

　　Do you see any other difference between the two flowers? Yes; in the pin-eyed flower the dust-spikes are placed half-way down the tube, but in the other they are right at the top, and form its "thrum" eye.

　　你还看见这两种花有什么不同了吗？有的：长花柱花中，花药的位置，在花冠筒的下半边；而在别的花中，花药在最顶端，形成了花的线头形状的花心。

　　You know that every flower needs pollen from some other flower to help to make its seeds, and that bees and other insects carry this pollen about when they are gathering honey. Let us see how the two kinds of primrose flowers help each other to make seeds.

　　小朋友知道，每朵花都需要从别的花那儿拿到花粉，才能制造出自己的种子，蜜蜂和其他昆虫，在采蜜的时候，就能把花粉带来带去。咱们再看看，这两种报春花是怎么互相帮助，制造种子的。

　　When a bee pushes its trunk down into a thrum-eyed primrose, it gets part of its head covered with pollen. When it goes to a pin-eyed flower, that part of its head rubs against the top of the style and supplies it with pollen.

　　蜜蜂把喙探进“短花柱花”的时候，头上的一个地方会染上花粉。蜜蜂再落到“长花柱花”上，头的这个地方就蹭到了柱头，把花粉送给了它。

　　A pin-eyed flower will leave its pollen on a different part of the insect's head. But this is just the part that will rub against the style of a thrum-eyed flower. So you see that the two kinds of primrose flowers exchange pollen with each other by means of the bees, and so help each other to make good seeds.

　　“长花柱花”还会把花粉，留在昆虫头部的另一个地方，蜜蜂正好用这个地方，蹭到“短花柱花”花的柱头。所以这两种报春花，就是通过蜜蜂来传递花粉的，互相帮助，制造出优良的种子。