Apetalae

… There is no strong theory yet on how to classify dicotyledons. However, tentatively, they are classified into the following groups: those with separate carpels (Polycarpicae), such as Magnoliales, Ranunculales, and Nymphales; those with stamens arranged downwards, such as Hypericales and Malvaceae; those with small unisexual flowers in a tail-like inflorescence (Apetalae), such as Juglandales and Fagales; those with an independent central placenta or basal placenta (Centrospermae), such as Caryophyllales and Polygonales; those with persistent calyx tubes, constant number of floral elements, and whorls, such as Rosales, Myrtelles, and Apidales; those with sympetalous flowers in superior ovaries, such as Lamiales; and those with sympetalous flowers in inferior ovaries, such as Asterales. [Michio Tamura]. …

*Some of the terminology that mentions "Apetalae" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…　双子葉植物を大分けする有力な説はまだない。しかし一応は，モクレン目，キンポウゲ目，スイレン目など離生心皮をもつ群(多心皮類Polycarpicae)，オトギリソウ目，アオイ目など上より下へつくられるおしべをもつ群，クルミ目，ブナ目など小型の単性花を尾状の花序につける群(無花被あるいは無花弁類Apetalae)，ナデシコ目，タデ目など独立中央胎座ないしは基生胎座をもつ群(中心子群Centrospermae)，バラ目，フトモモ目，セリ目など萼が宿存して萼筒をつくり，花要素の定数化と輪生が確立する群，シソ目など子房上位で合弁花をもつ群，キク目など子房下位で合弁花をもつ群などに大別される。【田村 道夫】。…

※「Apetalae」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報