As plants in conservatories and rooms the following are cultivated: species of _Gymnogramme_ (tropical America), _Lomaria_, _Nephrolepis_, _Pteris_ (_P. serrulata_, _cretica_). Officinal. _Aspidium filix-mas_, rhizome and the withered petioles.--Species of _Alsophila_ and _Cibotium_ give Penghawar Djambi. The rhizome of _Pteridium aquilinum_, var. _esculentum_, contains so much starch that it is used as food. The other orders of true Ferns deviate from the Polypodiaceæ, especially in the formation of the annulus, the bursting of the sporangium and its mode of attachment and development, and in the differences in the formation of the prothallium, etc. The principal are:-- Order 2. =Hymenophyllaceæ.= To this order belong the lowest and most Moss-like Ferns; the leaves, with the exception of the veins, are most frequently formed of _only one layer of cells_, and consequently stomata are wanting; the formation of the prothallium also somewhat resembles the Mosses. Sori marginal, on the _extremities of the vascular bundles_, and surrounded by a _cupular indusium_. The sporangia are sessile, with equatorial annulus. _Hymenophyllum_ (_H. tunbridgense_, European). _Trichomanes_ (_T. speciosum_, European). Species about 200, which live especially on rocks and trees in damp and shady tropical forests. Some have no roots. Order 3. =Cyatheaceæ.= Annulus _complete_ and oblique. To this order belong, principally, the tree-like Ferns with palm-like habit. The number of species is about 200, they are all tropical and form forests in some regions of Australia. _Cibotium_ and _Dicksonia_ have marginal sori, with cupular, basal indusium. (The stem of _D. antarctica_ is covered with aerial roots.) _Alsophila_ (without indusium); _Cyathea_ with cupular, inferior indusium (Fig. 212 _E_). [Illustration: FIG. 213.--_Gleichenia_: _A_ part of a leaf with sori; _B_ a single sorus.] Order 4. =Gleicheniaceæ.= Sporangia with equatorial annulus, and longitudinal dehiscence, most frequently groups of 3–4 in sori without indusium (Fig. 213). _Gleichenia_: the apical growth of the leaves continues for a long time. Order 5. =Schizæaceæ.= Annulus apical. To this order belongs _Aneimia_, which is so commonly cultivated in conservatories. The two lowest pinnæ are metamorphosed, having no leaf parenchyma and being covered with sporangia. _Schizæa. Mohria. Lygodium_, a climber, whose leaves have unlimited growth and attain a length of several metres. About 70 species. Tropical. Order 6. =Osmundaceæ.= The sporangia have at the apex a lateral group of strongly thickened cells, which gradually pass over into the ordinary cells. The sporangia open by a longitudinal cleft. Indusium wanting. _Osmunda_ bears the sporangia upon peculiar, branched pinnæ, without parenchyma (the uppermost in the leaf). _O. regalis_ (Royal-Fern): European.