SPADICIFLOR^l. 397 



Order, together with the spathe met with in most cases, give the group a 

 character of habit which is generally very distinct ; some genera, however, 

 such as Acorus, depart from this form, and approach the Typhacese or 

 Cyperacese in aspect, with which the spadiciflorous structure at the same 

 time unites them ; they have further relations with the Pandanacese, and 

 also with the Palmaceae, in w^hich the inflorescence shares the spadici- 

 liorous characters ; and although the perianth is much more definite and 

 highly developed there, its presence in Acorus and Orontium of this 

 Order forms a connecting link. Lemnaceae are closely related here, and 

 perhaps should be regarded as the simplest form of Aroids; but the 

 conditions are so simple there that it is more convenient to separate them. 

 From Naiadaceae, in which the inflorescence is moreover hardly spadi- 

 ciflorous, the Aroids are easily distinguished by the character of their 

 seeds. The Araceae are either herbs, sometimes with very large leaves 

 and spathes, or their stem becomes more or less developed and branched, 

 so as to give them a shrubby character ; while others are epiphytic and 

 climbing plants, producing aerial roots like the Orchids. The leaves are 

 of the most varied character in this Order. 



Distribution. A large Order, not numerous in temperate climates, but 

 represented there by Arum, Calla, and Acorus. Most abundant in the 

 tropics, especially in forests and the lower regions of mountains. 



Qualities and Uses. The juices of the Aroids are generally acrid and 

 dangerous, some very poisonous ; but heat seems to dissipate the noxious 

 principles. The acridity is replaced by agreeable aromatic pungency in 

 Acorus Calamus. The corms and rhizomes often contain much starch, 

 which is extracted, and purified by washing, from Arum maculatum 

 (Portland Arrowroot) ; while the corms of Arum indicum, Amorpho- 

 phollus campanulatus, Caladium bicolor, Colocasia esculenta ("Cocoes'' and 

 "Eddoes," West Indies), C. macrorhiza ("Tara," South-Sea Islands), and 

 C. himalayensis are eaten, roasted or boiled. The rhizomes of Calla palus- 

 tris are also eaten after thorough washing. Diefferibachia seyuina, the 

 u Dumb-cane " of the West Indies, is so called from the inflammation of 

 the tongue and fauces produced by chewing it; Dracontium pertusum 

 (remarkable for its perforated leaves) has blistering properties. Symplo- 

 carpus fcttidus, the " Skunk-cabbage " of North America, is very foetid, as 

 is also *the newly opened inflorescence of Arum Dracuncidus, A. italicum, 

 and others, which produce sickness and serious indisposition in some 

 constitutions. Richardia africana is the white spathed " Trumpet-Lily " 

 of our conservatories. The species of Philodendron are very handsome 

 stove-plants. Anthurium Scherzerianum is particularly noticeable for its 

 brilliant scarlet spathes and its twisted spadix. 



LEMNACEAE are minute stemless plants, floating free on the water, 

 either destitute of distinct stem and foliage, as in Lemna, or consisting 

 of tufts of leaves connected by filiform runners (Pistia) ; producing few 

 monoecious flowers, surrounded by a spathe, from a chink at the edge or 

 upper surface of the frond, or in the axils of the leaves ; stamens definite, 

 sometimes monadelphous ; ovary 1-celled, with 1 or more erect ovules, 

 from the base of the cell; fruit a 1- or more-seeded utricle; embryo 

 straight, in the axis of fleshy perisperm. Lemna, the genus to which the 

 common Duckweeds belong,' is one of the simplest representatives of the 



