70 SUB-ALPINE PLANTS 



of Hautes-Alpes ; but it grows in bushy places among the sihceous 

 hills in the Pyrenees and Western Europe from Portugal to the 

 South- West of Norway, and in Britain. 



CRUCIFER^ 



Herbs or rarely under-shrubs with alternate leaves, and no 

 stipules. The flowers in terminal racemes, which are usually very 

 short, but lengthen out as flowering advances. Sepals 4. Petals 4, 

 equal, or the two outer larger. Stamens 6, of which two are generally 

 shorter. Ovary solitary, 2-celled. Style single, often very short, 

 with a capitate or 2-lobed stigma. Fruit a pod, divided into 2 cells 

 by a thin partition, from which the valves generally separate at 

 maturity ; or, in a few genera, the pod is i-ceUed and indehiscent, 

 or separates into several transverse joints. 



An extensive family widely spread over the globe, but chiefly in 

 the northern hemisphere. The characters of the genera are chiefly 

 derived from the pod and seed ; therefore to name a Crucifer it is 

 almost necessary to have the specimen in fruit. 



Arabis L. 



Annuals or perennials, usually erect and hairy, at least at their 

 base, with a spreading tuft of radical leaves, which are occasionally 

 lobed ; the stem-leaves undivided, sessile or clasping the stem. 

 Flowers white or purple. Pods long and Hnear, the stigma nearly 

 sessile, the valves flat or slightly convex. Seeds more or less 

 flattened, often winged. 



A large genus spread over the temperate regions of the northern 

 hemisphere. 



Arabis alpina L. Alpine Rock-cress. 



Stem 3-12 inches high, covered like the leaves with forked hairs. 

 Leaves coarsely toothed, often with a wavy margin ; root-leaves 

 wedge-shaped ; stem-leaves ovate or ovate-lanceolate. Petals 

 white, rather large, 3 lines long. Siliquas spreading, flat, about an 

 inch long. Seed surrounded by a narrow membranous rim. Very 

 polymorphic. Leaves thin and glabrescent when in shady places 

 under rocks or trees. 



Damp rocky places, especially on limestone in the Alps and 

 sub-Alps up to 10,000 feet, and often descending to the plains in 

 the beds of streams. May to August. 



Distribution. — Carpathians, Eastern, Central, and Western Alps ; 

 Jura, Auvergne, Cevennes, Pyrenees, Corsica, Riesengebirge, Harz 

 and Westphalia, Scandinavia (to above the birch limit), Siberia, 

 Himalaya. 



Easily cultivated from seed in sandy loam, as indeed many 



