SPADICIFLORJ). 303 



TypJia (Bulrush, Reed-mace) has a long, cylindrical, brown 

 spike, the lower portion bearing ? -flowers, and the upper <$ -flowers, 

 which is divided into joints by alternate leaves. The $ -flowers 

 have 1 carpel. The perianth is wanting, represented by a number 

 of fine, irregularly-placed hairs; pistil unicarpellate. Fruit a nut. 



The two genera, according to some, are related to the 2nd order In both 

 genera native species are found. The pollination is effected by the wind, and 

 consequently the anthers project considerably, and the stigma is large and 

 hairy. Typlia is protandrous, Sparganium protogynous. The small, fine 

 hairs surrounding the nut of Typha. assist in its distribution by the wind. 

 Fossil Typhas in the Tertiary. 



Order 5. Aracese (Arums). The flowers are small, and always 

 borne without bracts or bracteoles on an unbranched, often very fleshy 

 spike, which is enclosed by a spathe, often petaloid and coloured 

 (Fig. 3 ',">!). The fruit is a Lerry. Outer integument of the seed 

 fleshy. The leaves have generally sheath, stalk, and blade with 

 distinctly reticulate venation ; they are chiefly cordate or sagittate 

 (Fig 302), seldom long with parallel venation as in the other 

 Monocotyledons (Acorus, Fig. 300). The Aracege are quite 

 glabrous, generally perennial herbs with tubers or rhizomes. Many 

 have latex. For the rest the structure of these plants varies ; for 

 example, while some have a perianth, in others it is wanting ; in 

 some the perianth-leaves are free, in others united ; some have 

 hermaphrodite flowers, but the majority unisexual (monoecious) ; 

 some have free, others united stamens ; the ovules are 

 orthotropous, anatropous, or campylotropous, erect or pendulous ; 

 the ovary is 1-many-locular ; some have seeds with endosperm, 

 others without. In habit there are great differences. While some, e.g. Colo- 

 casia (Fig. 302), have a thick, more or less upright stem, with leaf- scars, but not 

 woody, others are climbers, epiphytic, and maintain themselves firmly by means 

 of adventitious roots, on the stems and branches of trees, or even on steep rocks, 

 e.g. Pliilodendron ; the cordate, peuninerved leaf is the most common (Fig. 

 302), but various braucbed forms appear ; the pedate leaves of Helicophyllum, 

 Draciincttlus, etc., are cymosely branched ; the leaves of filonstera delicioxd, 

 perforated by tearing, should be noticed (the vascular bundles while ia the 

 bud grow faster thun the tissue between them, causing the latter to be torn, 

 and the leaf perforated). With regard to the anatomical structure, the 

 presence or absence of latex, raphides, resin-passages, groups of mucilage- 

 cells should be noted. Engler makes use of these anatomical peculiarities for 

 a scientific arrangement of the order. 



A. OKONTIEJE, CALAMUS-GROUP. $ , hypogynous flowers of a 

 completely formed monocotyledonous type (number in the whorls 

 2, 3, or 4). Acorus (A. calamus, Sweet-flag) has a regular, 



