Seed and Seedling of Acorus calamus

Abstract

1. Acorus calamus L., which fails to produce seed in Europe fruits freely in Minnesota, where it is probably native.2. The fruit is a 3-celled, gelatinous, dry berry containing usually 5-7 orthotropous, ovoid, somewhat angled seeds pendent from an axillary placenta. The cylindrical embryo lies in the axis of theendosperm, which is surrounded by a thick callous perisperm. The seed coat is made up of a thin tough tegmen surrounded by a thicker spongy testa. 3. As the seed germinates the tip of the cotyledon remains in the seed as an haustorial organ and lifts it into the air as growth con-tinues. The seedling immediately becomes green and develops absorbing hairs so that it is early independent. The single vascular bundle of the cotyledon passes directly down into one pole of the diarch root while the midrib of the first plumular leaf is directly continuous with the other pole.