GROUP IV. — PHANEROQAMIA : DICOTTLEDONES : MONOCHLAMYDE^G. 579 



leaf has a pair of membranous stipules. In the inflorescence the leaves (bracts) 

 are placed singly, and are finally represented only by their stipules. In the ? 

 inflorescence, which somewhat resembles a fir-cone, a rudimentary shoot is 

 present in the common axil of each pair of stipules, and bears two flowers 

 on each side ; it seems at first sight as if two flowers were developed in the axil 

 of each stipule (Fig. 380 B). All the scales and bracts are covered, especially on 

 the upper surface, with numerous yellow glands. In the ^ inflorescence the 

 shoot which bears the flowers is well developed. 



Order 4. Ulmacej;. Ovary dimerous, sometimes bilocular, but 

 generally unilocular by abortion. Ovule suspended and solitary. 

 Flowers mostly ambisporangiate, witb a 4-6-partite perianth 

 (Fig. 381 A). Woody plants devoid of milky juice : leaves alter- 

 nate, with caducous stipules. The inflorescences (glomerules) are 

 borne directly in the axils of the leaves. 



In the genus Ulmus the compact dichasial inflorescences are developed in the 

 axils of the leaves (either persistent or deciduous), of the previous year, and 

 they are invested by bud-scales ; one or more 

 flowers are developed in the axil of each of the 

 more internal scales (bracts), and they open before 

 the unfolding of the leaves. The ovary is some- 

 times bilocular. The fruit is a samara, that is, 

 an achene with a broad membranous wing (Fig. 

 381 B). The leaves are alternate, and always 



oblique. The annual shoots have no terminal „ „„, , „. 



, / , . ^ T m . ^^"- 381.-X Flower of 



bud, and so they form a sympodmm. Two species u^,^,., .^.^t,,^^ (.^^^.j , ^ 



of Elm are indigenous in England. Ulmus cam- bract ; j» perianth ; a stamens. 



pestris, the common Elm, and Ulmus montana, B Fruit (samara) (nat. size) : 



the broad-leaved Wych, or Scotch, or Mountain '" . "membranous margin 



Elm : the former has rather slender branches, 



leaves with distinct petioles and crenate serrate margins, somewhat narrow at 



the base, and a seed which is above the centre of the samara ; the latter has thick 



horizontally-spreading branches, leaves with very short petioles and doubly 



serrate margins, broad at the base, and a seed which is cetjtral in the samara. 



Celtis auKtralis, from Southern Europe and C. occidentalism from North America, 



are often cultivated as ornamental trees ; their flowers are polygamous, and 



are placed singly or several together in the axils of the oblique accuminate 



leaves : the fruit is drupaceous. 



Cohort III. Amentales. The flowers, which are always dicli- 

 nous and generally moncocious, are arranged in catkins (amenta). 

 The perianth, when it is present, consists typically of 5 (|) 

 segments ; or it may deviate from the type so as to consist of four, 

 (i.e. 2-1-2), or six (i.e. 3 -f- 3) segments : the stamens, when their 

 position can be determined, are superposed on the segments of the 

 perianth for the reason given in the case of the Urticales (see p. 576). 



