A SYNOPSIS OF THE PLANT KINGDOM 



43 



Geranium have been used as remedies for wounds, 

 others for dysentery, and the like; some have been used 

 as stimulants. Erodium moschatum is valued because of 

 a very strongodor of musk. The resinous stems of Mon- 

 sonia (South Africa) burn readily, and have been used 

 for torches. The most important economic genus is 

 Pelargonium, cultivated for ornament. The foliage of 

 some Pelargoniums is glandular and very fragrant 

 ("rose geraniums"). Some species of Geranium also 

 are ornamental. The awn-like beak of Erodium fruits 

 have been used as hygrometers. 



Few genera are in cultivation in America as orna- 

 mental plants: Erodium (Stork's-bill); Geranium, 

 (Crane's-bill); Pelargonium (so-called "Geraniums"). 

 Sc\-oral cultivated genera, formerly included in the 

 Geraniacea:, are now placed in separate families, which 

 see, e.g., Impatiens (Balsaminaceso), Tropa;olum (Tro- 

 pjeolacea;), Oxalis and Averrhoa (Oxalidacese). 



105. Oxalidaceae (from the genus Oxalis, signifying 

 acid, from the sour taste of the foliage). OXALIS FAM- 

 ILY. Herbs, rarely shrubby: leaves usually compound: 

 flowers bisexual, regular; sepals 5, persistent, imbri- 

 cated; petals 5, convolute or imbricated, rarely united 

 at the base; stamens 10 in 2 whorls, the outer set oppo- 

 site the petals, filaments coherent below, those of the 

 outer set shorter, one or both sets with external glandu- 

 lar appendages at the base, hypogynous; ovary superior, 

 5-celled, with a persistent central column (as in Ge- 

 raniacese); styles separate: fruit an ordinary capsule 

 with each cell dorsally dehiscent, or a berry. 



The Oxalis family contains 7 genera and about 230 

 species, of which 220 belong to the genus Oxalis. They 

 are mostly of tropical and subtropical distribution. 

 Oxalis occurs chiefly in South Africa and South 

 America. The Oxalidacese were formerly united with 

 the Geraniacese, but differ in the fruit, which is a dehis- 

 cent capsule or a berry and does not break up into 

 separate carpels. 



The species of Oxalis are often bulbous or tuberous, 

 or the roots are enlarged as water-storage tissue. The 

 leaflets usually have a sensitive cushion at the base 

 (pulvinus) and show sleep-movements. The flowers of 

 many are dimorphic or trimorphic, i.e., have stamens 

 or styles of 2 or 3 lengths in the same species. The 

 seeds are forcibly ejected through the dorsal suture of 

 the capsule by the elastic separation of the outer layer 

 of the testa. 



Oxalis contains much oxalic acid, which may be 

 extracted for economic purposes. It is somewhat seda- 

 tive, and the sour taste has made some species useful 

 as salads. The starchy roots of some South American 

 species are used for cattle-fodder. The fruits of Aver- 

 rhoa are used in the tropics as a substitute for goose- 

 berries, which they resemble in flavor. 



Two genera are grown in America: Averrhoa (Caram- 

 bola), 1 species grown for shade and fruit; and Oxalis. 



106. Tropaeolaceae (from the genus Tropseolum, from 

 tropaion, a trophy; the leaves are shield-like, and the 

 flowers resemble a helmet). NASTURTIUM FAMILY. Fig. 

 29. Diffuse or climbing succulent herbs with alternate, 

 peltate or lobed leaves: flowers bisexual, irregular, 

 spurred; sepals 5, imbricated; petals 5, imbricated, 

 the upper two differing in shape from the lower three; 

 stamens 8, separate, somewhat perigynous; ovary 

 superior, 3-cclled, 3-lpbed, each cell 1-seeded; style 1; 

 stigmas 3: fruit splitting into 1-seeded, indehiscent 

 nutlets or drupelets. 



A single genus of about 35 species is found in the 

 mountainous regions from Mexico to Chile. The family 

 was formerly included in the Geraniacese, but is dis- 

 tinguished by its separate stamens, its indehiscent fruit- 

 lets, and a very peculiar method of embryo develop- 

 ment, in which the suspensor divides into three parts, 

 one part growing into the placenta, another out into 

 the ovarian cavity, and the third producing the embryo 

 on its apex. The spur of the flower is an outgrowth of 



the obliquely cup-shaped receptacle at the base of the 

 calyx, as in Pelargonium. 



The herbage of Tropseolum has an acrid taste like 

 cress, and is often used for salad, hence the common 

 name "nasturtium" or "Indian cress." 



In America, several species are grown for their showy 

 flowers. Tropseolum majus is the most widely known 

 species. T. peregrinum is the "canary-bird flower." 



107. Linaceae (from the genus Linum, the Latin name 

 for flax, from the old Celtic llin, a thread). FLAX FAM- 

 ILY. Fig. 29. Woody or herbaceous plants: leaves alter- 

 nate or opposite, rarely whorled, simple, entire: flowers 

 bisexual, regular; calyx of 5, persistent, imbricated 

 sepals, rarely 4-parted, with 3-fid lobes; petals 5, rarely 4, 

 convolute, clawed, the claw sometimes crested; stamens 

 5, alternate with the petals, with sometimes 5 additional 

 staminodia, or 10, 15, or 20, hypogynous, usually united 

 at the often glandular base; ovary 5-, rarely 3- or 4-, 

 celled or falsely 10-celled by the intrusion of the mid- 

 rib; ovules few; styles as many as the cells of the 

 ovary: fruit a capsule or drupe. 



There are 9 genera and about 120 species, of which 90 

 species belong to Linum. The Linaceae are related to 



29. GERANIACEJE: 1. Geranium, a, floral diagram; 6, fruit; 

 e, fruit dehiscing. TROP^EOLACE^:: 2. Tropseolum, flower. IsXir 



CE.K: 3. Linum, a, flower; 6, floral diagram. 



the Geraniacese and Oxalidacea;, but also show a rela- 

 tion to the Silenes in the Caryophyllacese. The many- 

 stamened genera suggest the Ternstrcemiaceae. The 

 family is most easily recognized by the simple, regular 

 pattern of the flower, and the numerical plan of 5 (or 4) 

 which is carried through all the floral parts. For this 

 reason, the flax was taken by the older botanists as a 

 pattern flower. 



Linum catharlicum (Europe) was formerly used as a 

 purgative. A fixed oil is extracted from the seeds of the 

 common flax (Linum usitatissimum) , which is used in 

 medicine as an emollient. The most extensive use of this 

 oil is in painting, its value being due to the property of 

 drying into a hard, waterproof coating. Flaxseed meal, 

 from which the oil has been expressed, is used for fodder 

 and for poulticing. The seed-coats of flax become very 

 mucilaginous when soaked, on which account flaxseed 

 has also been used as an emollient in the treatment of 

 coughs and colds. The cortical bast-fibers of the flax 

 have been used since earliest times in textile industries. 

 As the basis of linen cloth, flax is one of the most useful 

 of cultivated plants. Flax was probably Asiatic in its 

 origin. Many species of Linum are ornamental, but 

 are little grown. 



Two genera are cultivated in America: Linum, 

 with species of annual garden plants; and Reinwardtia, 

 with species of conservatory sub-shrubs from India. 



