Martin placed the lateral embryo, which occurs only in grasses, adjacent to the broad embryo at the base of his family tree of seed phylogeny. Since Poales and Poaceae are derived monocots, we questioned the evolutionary relationship between the lateral embryo and other kinds of monocot embryos. Information was compiled on embryo and seed characteristics for the various families of monocots, kind of embryogenesis for families in Poales and germination morphology of families with lateral (only Poaceae) and broad embryos. The kinds of monocot embryos are broad, capitate, lateral, linear fully developed, linear underdeveloped and undifferentiated, but only broad and lateral embryos are restricted to Poales. Asterad embryogenesis occurs in Poaceae with a lateral embryo and in Eriocaulaceae, Rapataceae and Xyridaceae with a broad embryo. In developing grass seeds, the growing scutellum (cotyledon) pushes the coleoptile, mesocotyl and coleorhiza to the side. In the organless broad embryo, the cotyledonary sector is larger than the epicotyledonary sector. During germination of grass seeds, the coleorhiza and then the coleoptile emerge, while in a seed with a broad embryo the elongating cotyledon pushes the epicotyledonary sector outside the seed, after which a root–shoot axis is differentiated at a right angle to the cotyledon inside the seed. Broad and lateral embryos are closely related; however, the lateral embryo is more advanced in seed/embryo traits and germination morphology than the other kinds of monocot embryos, suggesting that its position on the family tree of seed phylogeny should be higher than of the other monocot embryos.

中文翻译：

---

侧胚（草中）与其他单子叶胚的关系：状态升级

马丁将只出现在草中的侧胚放置在他的种子系统发育谱系树底部的宽胚旁边。由于 Poales 和禾本科是衍生的单子叶植物，我们质疑侧胚和其他种类的单子叶胚之间的进化关系。收集了有关单子叶植物各个科的胚胎和种子特征、Poales科的胚胎发生类型以及具有侧生（仅禾本科）和宽胚科的萌发形态的信息。单子叶胚的种类有宽胚、头状胚、侧生胚、线状完全发育胚、线状发育不全胚和未分化胚，但仅宽胚和侧生胚仅限于Poales。Asterad 胚胎发生在禾本科中具有侧向胚，而在毛茛科、萝卜科和 Xyridaceae 中具有宽胚。在草种子发育过程中，生长的盾片（子叶）将胚芽鞘、中胚轴和鞘兰推向一边。在无器官宽胚中，子叶节大于上子叶节。草种子发芽时，先有鞘根，然后是胚芽鞘，而在宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与里面的子叶成直角分化种子。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。生长的盾片（子叶）将胚芽鞘、中胚轴和鞘兰推到一边。在无器官宽胚中，子叶节大于上子叶节。草种子发芽时，先有鞘根，然后是胚芽鞘，而在宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与里面的子叶成直角分化种子。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。生长的盾片（子叶）将胚芽鞘、中胚轴和鞘兰推到一边。在无器官宽胚中，子叶节大于上子叶节。草种子发芽时，先有鞘根，然后是胚芽鞘，而在宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与里面的子叶成直角分化种子。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。在无器官宽胚中，子叶节大于上子叶节。草种子发芽时，先有鞘根，然后是胚芽鞘，而在宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与里面的子叶成直角分化种子。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。在无器官宽胚中，子叶节大于上子叶节。草种子发芽时，先有鞘根，然后是胚芽鞘，而在宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与里面的子叶成直角分化种子。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。而在具有宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与种子内部的子叶成直角分化。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。而在具有宽胚的种子中，伸长的子叶将上子叶部分推到种子外面，然后根茎轴与种子内部的子叶成直角分化。宽胚和侧胚密切相关；然而，侧胚在种子/胚性状和萌发形态方面比其他单子叶胚更先进，表明其在种子系统发育谱系树上的位置应高于其他单子叶胚。