516 



PART IV. CLASSIFICATION. 



FIG. 325. A <J flower of the Hop : p 

 the perianth ; o stamens. B Part of ? 

 inflorescence : p perianth ; / ovary, with 

 two stigmata (i) ; each flower is enclosed 

 in its bracteole (d) ; s scale, i.e. one of the 

 two stipules, from the common axil of 

 which the branch bearing the flowers 

 springs. 



Cannabis sativa, the Hemp, a native of Asia, is cultivated throughout 

 Europe. The $ inflorescences are panicled dichasia or scorpioid cymes, 

 and are disposed on both sides of a rudimentary shoot at the apex of the 



plant ; the $ flowers are placed singly 

 on both sides of a similar shoot, which 

 bears secondary shoots in the axils of 

 its leaves, each having two flowers. 

 The tough bast-fibres are used in 

 weaving and for ropes ; the seeds 

 contain a great deal of oil. Humulus 

 Lupulus, the Hop, is both cultivated 

 and found wild. The stem, which 

 has the peculiarity of twining to the 

 right, bears its leaves in pairs ; each 

 leaf has a pair of membranous sti- 

 pules. 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. 325 B). All the scales and bracts are covered, especially 

 on the upper surface, with numerous yellow glands. In the $ inflores- 

 cence the shoot which bears the flowers is well developed. 



Order 4. ULMACE^E. Ovary dimerous, sometimes bilocular, but 

 generally unilocular by abortion. Ovule suspended and solitary. 

 Flowers mostly monoclinous, with a 4-6-partite perianth (Fig. 326 

 A). Woody plants devoid of milky juice : leaves alternate, with 

 caducous stipules. The inflorescences (glomerules) are borne di- 

 rectly 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 sometimes bilocular. The fruit 

 is a samara, that is, an achene with a broad 

 membranous wing (Fig. 826 B}. The leaves 

 are alternate, and always oblique (p. 33). The 

 annual shoots have no terminal bud, and so 

 they form a sympodium (see p. 21). Two 

 species of Elm are indigenous in England: 

 Ulmus campeztris, the common Elm, and Ulmus 



FIG. 326. 4 Flower of 

 Ulmus monlana (mag.) : d 

 bract ; p perianth ; a stamens. 

 B Fruit (samara) (nat. size) : 

 m membranous margin 

 (wing). 



