NETTLE FAMILY 427 



r. Ulmus. — Trees with distichous leaves ; perfect flowers in 

 clusters ; bell-shaped, 4 — 5 cleft, persistent perianth ; styles 2 ; 

 fruit a rounded, 1 -seeded samara. 



2. Humulus. — Twining plants with opposite lobed leaves; 

 dicecious flowers ; staminate flower with 5 -leaved ■perianth and 5 

 stamens ; carpellate flowers in a catkin of large brads ; styles 2. 



3. URTfCA. — Herbs with opposite leaves and stinging hairs; 

 flowers imperfect ; perianth 4 — 5-cleft ; style 1. 



4. Parietaria. — Herbs with scattered, exstipulate leaves ; poly- 

 gamous, 4-merous flowers ; style 1. 



1. Ulmus (Elm). — Trees with distichous, oblique, rough leaves, 

 with stipules falling early ; flowers perfect, in clusters, appearing 

 before the leaves ; .perianth bell-shaped, 5- rarely 4-cleft, persistent \ 

 stamens 4 — 5 ; styles 2 ; ovary superior, 1 — 2-chambered, with an 

 ovule in each chamber ; fruit a thin, membranous, 

 1 -seeded samara. (Name, the Classical Latin 

 name of the genus.) 



1. U. scdbra (Wych Elm). — A large tree, with 

 furrowed bark ; few suckers ; downy twigs ; large, i 

 irregularly doubly serrate, obliquely cordate, I 

 acuminate, thick leaves, with short stalks ; samara ' 

 orbicular, with the seed-cavity below the middle. — 

 Woods, chiefly north of the Trent ; common. — 

 Fl. March, April. Perennial. 



2. U. glabra. — Usually a somewhat smaller tree, 

 producing numerous suckers ; twigs nearly smooth ; 

 leaves small, thin, shining and nearly glabrous, FRUIT ^ ELM . 

 except in the angles of the veins on their under 



surfaces, with long stalks ; samara obovate, with the seed-cavity 

 near the upper end. Chiefly south of the Trent. — Fl. March — May. 

 Perennial. 



There are also a number of other forms of elm, apparently 

 hybrids between these two, of which the best-known is U. 

 surculbsa, the English or Hedgerow Elm, a lofty tree, often send- 

 ing out horizontal lower branches, producing abundant suckers, 

 downy branches and leaves, with long petioles, aud numerous 

 obovate samara, like those of U. glabra, but not perfecting its seed. 



2. Humulus (Hop). — Twining herbs with opposite lobed leaves 

 with connate stipules ; minute, dicecious flowers, the staminate in 

 panicles, with perianth of 5 imbricate leaves and 5 stamens ; the 

 carpellate 2 together in the axils of numerous bracts in a catkin ; 

 styles 2. (Name said to be from the Latin humus, rich soil, in 

 which the plant flourishes.) 



