DICOTYLEDONES : POLYPETALJS : DISCIFLORJ1. 613 



Order 2. LINAGES. Disc generally a whorl of 10 small extra- 

 staminal glands : formula K5, (75, ( | A f 5 + 5), G ( ^ : flowers acti- 

 nomorphic, rarely all the whorls are tetramerous : stamens mona- 

 delphons at the base; the whorl of stamens opposite to the petals 

 is replaced by staminodia : each loculus of the ovary contains two 

 ovules, and is often divided into two by a more or less complete 

 false dissepiment : seed usually contains endosperm : capsule septi- 

 cidal. Herbs or shrubs ; leaves simple, entire, with or without 

 stipules. 



Linum usitatissimum is the Flax : the strong bast-fibres are used in weaving 

 linen ; the seeds contain oil ; the walls of the outer cells of the testa are muci- 

 laginous. There are several British species of Linum. Badiola, the other 

 British genus, has tetramerous flowers. 



Order 3. EEYTHEOXYLACE^. Flowers regular: petals five, with 

 a ligular appendage : stamens ten, connate at the base by means 

 of a disc and forming a tube : ovary 2-3-locular, with one sus- 

 pended anatropous ovule in each loculus : seed with endosperm. 



The wood of most of the species contain a red dye. The leaves of Erythroxy- 

 lon Coca are used as a stimulant : they contain cocain. 



Order 4. OXALIDACEJ:. Disc present as small glands at the base 

 of the antipetalous stamens, or of all of them : flowers actino- 

 morphic; formula I5 7 (75, (1-45 + 5), 67 '^ ; the antipetalous 

 stamens are sometimes staminodial ; those which are opposite to 

 the sepals are the longest : ovules numerous ; fruit a capsule, or 

 more rarely a berry ; seed containing endosperm. Herbs, with 

 compound (ternate), generally exstipulate leaves. 



Oxalis Acetosella, the Wood- Sorrel, is frequent in woods; it contains much 

 potassium oxalate. The tuberous roots or underground stems of some American 

 species, as 0. esculenta, crenata, and Deppei, contain much mucilage, and are 

 used as food. Some species (e.g. 0. gracilis) show trimorphic heterostylism 

 (p. 455) : others (e.g. 0. Acetosella), have cleistogamous flowers (p. 453). The 

 leaves of Oxalis and Averrhoa show sleep-movements : those of Biophytum are 

 sensitive to touch. 



Order 5. BALSAMINACEJE. Disc 0: flowers irregular, dorsi ventral ; 

 formula K5, C5, I .40 + 5, G ( ^-: the posterior sepal is spurred, and 

 the two anterior are small or absent : the anterior petal is large : 

 ovary 5-locular ; ovules numerous ; the fruit is loculicidally septi- 

 fragal, the valves separate elastically and roll upwards, so that the 

 seeds are projected to some distance; seed without endosperm. 

 Herbs, with simple exstipulate leaves. 



