-116 



DICOTYLEDONES. 



Family 12. Gruinales. 



The flowers are hypogynous, g , polypetalous, usually regular 

 (except Pelargonium, Trop&eolaceze, BalsaminacedB) and throughout 

 5-merous : S5, P5, A5 + 5, or 5 + 0, G5 (epipetalous) . The stamens 

 soon fall off and are oMiplostemonous, often united at the base 

 (monadelphous) ; the corolla- stamens are in some completely sup- 

 pressed (e.g. Balsaminacese, Fig. 438), in others reduced to teeth 

 (Linum, Fig. 431; Erodium), The Tropseolacede have 3 carpels 

 and only 8 stamens (Fig. 437). Ring-like nectaries are not pre- 

 sent, but at most only glandular bodies, borne outside the base of 

 the stamens. Ovaries many-locular. The ovules as a rule are 

 pendulous, with the micropyle directed outwards (Fig. 431, 5), 

 and the radicle therefore also points outwards. Usually herbs. 

 Related to the Columniferce. 



Order 1. Oxalidacese. Most of the species are herbs with 

 rhizomes ; the leaves are stalked, compound, with entire leaflets 

 which are folded and bent backwards in 

 the bud (and in the sleep position), ex- 

 stipulate ; some species have sensitive 

 leaves. The flowers (Fig. 429) are re- 

 gular, and have S5, P5, which are twisted 

 to the left or right in aestivation, A5 + 5, 

 all united at the base (monadelphous), 

 gynceceum 5-car pell ate, styles 5 free, stig- 

 mas capitate, ovary 5-locular, ovules 

 numerous. The fruit is a capsule opening 

 with clefts on the dorsal sutures through 

 which the seeds are ejected, while the 



fleshy, external layer of the testa springs off elastically. Embryo 

 straight. Endosperm. 



Oxalis (Wood-Sorrel). Leaves digitate. Species also occur with phyllodia, i.e. 

 leaf-like petioles placed vertically without lamina ; a few have pinnate leaves. 

 The flowers are situated singly or in dichasia, and unipared scorpioid cymes. 

 The pollination is effected by insects. Some species are trimorphic (long-, 

 short-, medium-styled flowers) and some, e.g. O. acetosella, have cleistogamic 

 flowers in addition to the ordinary ones. Glands are found on the outer side of 

 the corolla-stamens or of all the stamens. 0. tetraphylla and others have 

 adventitious edible roots, resembling tap-roots. Averrhoa is a tropical tree, with 

 berries and pinnate leaves. 



235 species (205 belong to Oxalis)', chiefly in S. Africa and Trop. America. 

 Oxalate of potash is contained in the leaves of Oxalis. 



FIG. 429. Diagram of Oxalis 

 acetosella. 



