URTICIFLOR^E. 351 



40 species ; Temperate. Myrica gale (Sweet-gale, Bog-myrtle) has been used 

 in the preparation of beer (Sweet-willow beer) on account of its resinous essential 

 oil. M. cerifera (N. America) and species from the Cape, M. quercifolia and 

 others, form wax on the fruit which is used in the preparation of candles. 



Family 5. Urticiflorae. 



The flowers are regular, hypogynous, nearly always unisexual, 

 small and insignificant, with single, green perianth of 4-5 leaves. 

 Stamens 4-5, placed opposite the leaves of the perianth. Ovary 

 formed of 1 or 2 carpels, most frequently unilocular, with one 

 ovule (Fig. 340). The fruit isanut, more rarely a drupe, with one 

 seed, generally endospermous. The Nettles are the sole order in the 

 family which has only one carpel (1 stigma) ; this turns the posterior side to 

 the front (Fig. 340). The others have two carpels (2 stigmas) but the anterior 

 only is fertile (Fig. 346) except in a few Ulmaceaa and Moraceae. 



The majority arj trees or shrubs with petiolated leaves, stipu- 

 late ; rough hairs are very frequently developed upon the leaves 

 The flowers are very often crowded together in the inflorescence, 

 which is rarely catkin-like. Peculiar aggregations of fruits are 

 found in some orders. Latex and tough bast, which is used techni- 

 cally, are also frequently found. Cystoliths are found in the 

 epidermis of many species of Ficus, Urtica, and others. Wind- or 

 self-pollination is most common, as in the Querciflorae and JuglandifloraB. In 

 the Urticaceae, Murus and some others, the stamens lie incurved in the bud, 

 and when ripe straighten themselves suddenly and elastically, and thus small 

 clouds of pollen-grains are ejected with considerable violence on to the stigmas, 

 which are often provided with brush-like hairs (Fig. 341). The formation of 

 honey does not take place. 



Order 1. Ulmaceae (Elms). Trees or shrubs without latex. 

 Leaves simple, arranged in two rows (divergence |-), oblique (the 

 inner side, nearer the axis, being the larger), strongly penni- 

 nerved, dentate, hispid; stipules deciduous. In opposition to the 

 other Nettle-like plants the flowers are often with a united 

 cup- or saucer-like, generally 4 (5)-6-divided perianth, and a 

 corresponding or larger number of opposite erect stamens. The 

 gynceceum has two carpels (2 stigmas), generally one loculus with 

 one pendulous, anatropous or amphitropous ovule, 1 seldom two 

 loculi and 2 ovules. Fruit one-seeded (nut or drupe). Embryo- 

 without endosperm. 



A. TJiMVJE. The fruit is a winged nut (Fig. 339), the embryo 

 straight, without endosperm. Anthers extrorse. Ulmus (Elm). 



1 The pollen-tube in Ulmus does not enter the ovule through the micropyle. 

 W. B. A A 



