The Foundations Of The Origin Of Species

Excerpt-But turning to plants we find same class of facts. I do not refer to seeds not ripening, perhaps the cause, but to plants not setting, which either is owing to some imperfection of ovule or pollen. Lindley says sterility is the [curse] bane of all propagators,--Linnæus about alpine plants. American bog plants,--pollen in exactly same state as in hybrids,--same in geraniums. Persian and Chinese{73} lilac will not seed in Italy and England. Probably double plants and all fruits owe their developed parts primarily «?» to sterility and extra food thus «?» applied{74}.