DICOTYLEDOXES ; POLYPETALJl : DISCIFLORJ:. 613 



Order 2. Linace^e. Disc generally a whorl of 10 small extra- 

 staminal glands : formula K^, (75, ( I J. f 5 + 5), G^^ : flowers acti- 

 nomorphic, rarely all the whorls are tefcramerons : 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 usitatUsimum 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. Erythroxylace^. 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 Erijlhroxy- 

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



Order 4. Oxalidace^. Disc present as small glands at the base 

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

 morphic; formula iC5, C5, ( 1^5 + 5), G'^ ; 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 (temate), 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, crenaia, and Deppei, contain much mucilage, and are 

 used as food. Some species {e.g. O. gracilis) show trimorphic heterostylism 

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

 leaves of Oxalis and Averrhoa show sleep'movemeuts : those of Biophytum are 

 sensitive to touch. 



Order 5. Balsam inacej;. Disc 0: flowers irregular, dorsiventral ; 

 formula iio, 05, I ^0 + 5, G^^: the posterior sepal is spun-ed, 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. 



