The very numerous and exceedingly small seeds have _no endosperm_, and have a somewhat _spherical embryo without any trace of external organs_. The testa is membranous and loose. The Orchids are _all perennial herbs_ with diverse habits and varying morphological structure (see the genera); the leaves are scattered, of the usual Liliaceous form, and the inflorescences in all cases are _racemes or spikes_ (sometimes branched), with subtending bracts, but without bracteoles. The forms which are the least modified are described first. =1.= APOSTASIEÆ. The perianth-leaves are almost alike and free. The column is straight, with 3 equally-developed stigmas. _Neuwiedia_ has 3 perfect stamens (1 median of the outer whorl, and 2 lateral of the inner whorl); _Apostasia_ has only 2 perfect (inner lateral) and one barren (the median of the outer whorl), which however may be entirely wanting. The 3 _posterior_ stamens are entirely suppressed. The pollen is powdery. The ovary is 3-locular with axile placenta. 7 species (Tropical East India, Australia). [Illustration: FIG. 319.--_Cypripedilum calceolus_: 1 front view of the flower; 2 lateral view, after the removal of all the perianth-leaves with the exception of the labellum, which has been divided longitudinally; 3 the stylar-column; _ov_ ovary; _s_-_s_ exterior, _p_ interior perianth; _p’_ the labellum; _a_ the two fertile stamens; _a’_ the staminode; _st_ the stigma; _i_ entrance for the insects; _ex_ exit.] =2.= CYPRIPEDILEÆ.[31] The flower is strongly zygomorphic with a large boat-shaped labellum. There are two perfect stamens belonging to the _inner_ whorl, and the median anterior (later on the posterior) stamen of the outer whorl is transformed into a large, barren, shield-shaped body (Fig. 319). _Selenipedilum_ has a 3-locular ovary, but _Cypripedilum_ (Ladies’-slipper) has a unilocular ovary with 3 parietal placentæ--the typical structure for the Orchids. The pollen-grains are _separate_ (not in tetrads) and all the 3 lobes of the stigma are constructed to receive them. This group is therefore, next to the Apostasieæ, the least modified among the Orchids; in all the following groups, one of the lobes of the stigma is differently developed from the others, and there is only one stamen.--Terrestial Orchids.--~The pollination of _C. calceolus_ is effected by the forcible entrance of insects into the boat-shaped labellum (Fig. 319 _p’_) at _i_, and their escape at _ex_ (in 2) where the anthers are situated; in this way the stigmas will first be touched and then the anthers. The pollen-grains are surrounded by a sticky mass in order that they may adhere to the insects.~