Pitcairnioideae

...The Bromeliaceae family is divided into three subfamilies based on the characteristics of the fruit and seeds. The Pitcairnioideae subfamily has a dry fruit (capsule) that splits open, leaves that usually have serrated edges, and are terrestrial or epiphytic. The Tillandsioideae subfamily has a fruit similar to the Pitcairnioideae, but the seeds have hair-like projections, the leaf margins are usually not serrated, and there are many epiphytic species. The Bromelioideae subfamily has a berry-like ovary that is fused, and the seeds lack projections. It is presumed that the primitive life form of the bromeliads was terrestrial, and evolved in two directions: from a group that was epiphytic and had many flowers in a spike shape, to a group that had well-developed water tanks and inflorescences surrounded by overlapping bracts, and further to a group that had a reduced number of flowers, down to a few or even one, and a group that produced a globular inflorescence with mutually fused ovaries, as typified by the pineapple (illustration). ...

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

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…パイナップル科Bromeliaceaeは果実と種子の特徴から3亜科に分類される。すなわち果実が乾果(蒴果)で裂開し，葉は通常鋸歯を有し，地上生や岩上生のピトカイルニア亜科Pitcairnioideae，前者と果実は似ているが種子に毛状の突起があり，葉縁は通常鋸歯がなく，着生種の多いティランドシア亜科Tillandsioideae，および子房の部分が合着し，液果になり，種子には突起を欠くブロメリア亜科Bromelioideaeである。　アナナス類の原始的な生活型は地上生で，多数の花を穂状につけるものから，着生で貯水槽のよく発達し，重なった苞片につつまれた花序をつける群，さらには花数が減少して数個から1個になる群といった着生生活への適応の方向と，パイナップル（イラスト）に代表されるような相互に合着した子房を有する球状の花序を生じる群の二つの方向に分化してきたと推定されている。…

※「Pitcairnioideae」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