500 



BOTANY 



escences and produce great quantities of dry pollen, and have large, 

 brush-like stigmas. Entomophilous forms adapted to insect-pollina- 

 tion occur in the Moraceae (e.g. the Fig). While in the Amentaceae 

 the structure of the flowers is subject to great variation, in the 

 Urticinae it is more uniform and constant. The almost invariable 

 presence of a perigone, the haplostemonous stamens, the herma- 

 phrodite or, by reduction, unisexual flowers are indicative of the high 



stage of development 

 attained by this family. 

 The fruit is either dry 

 and nut-like or dru- 

 paceous. 



Family Ulmaeeae. 

 — Flowers hermaphro- 

 dite or, as a result of 

 suppression, unisexual, 

 with four to six peri- 

 gone leaves ; stamens 

 straight in the bud; 

 ovary dimerous, uni- 

 locular, with one sus- 

 pended, ANATROPOUS 

 ovule. Woody plants 



WITHOUT MILKY JUICE, 



with pinnately veined 

 leaves and CADUCOUS 

 stipules (Fig. 449). 



This family comprises 

 tall trees with two- 

 ranked unsymmetrical, 

 hairy leaves. The flowers 

 are hermaphrodite and 

 clustered in the axils of 

 the .leaves of the preceding year. The fruit is a winged nut. 



Geographical Distribution. — The Ulmaeeae are forest trees of the temperate 

 and tropical zones. As examples of the genus Ulmus may be cited, Ulmus cam- 

 pestris, the Common Elm, and U. effusa, also the Witch-Hazel or Wych-Elm, Ulmus 

 montana, all native of Europe. Celtis australis, from Southern Europe, and the 

 Haekberry (Celtis oeeidentalis) from North America, both of which have drupaceous 

 fruits, are frequently cultivated as ornamental trees. 



Family Moraceae. — Flowers unisexual, usually with four perigone 

 leaves ; stamens STRAIGHT or inflexed in the bud ; ovary dimerous, 

 unilocular, with one suspended, anatropous ovule. Mostly trees or 

 shrubs, rarely herbs, with milky juice and CADUCOUS stipules (Fig. 

 450). 



The Moraceae are easily distinguishable from the Ulmaeeae by their 



Fig. 449. — Ulmu.1 campestris. 1, Flowering branch ; 2, branch 

 with leaves ; 3, a flower ; 4, the same, cut through longitudi- 

 nally ; 5, fruit. (After Wossidlo.) 



