CHAMBERS'S INFORMATION FOR THE PEOPLE. 



the latter being armed with tufts of spines ; the 

 stem is crowned by a woolly tuft, from which 

 spring the flowers. The hedgehog-thistle (Echi no- 

 cactus} has also a globose stem, but wants the 

 woolly head, and has its flowers springing from the 

 tufts of spines which arm the ridges. Some of 

 the species grow to an enormous size. A plant of 

 E. platyceras, growing at Kew, measured 9 feet 

 in height, 9^ in circumference, and weighed 

 upwards of a ton. The torch-thistle (Cereus) has 

 the stem angular, the projecting angles being armed 

 with spiny tufts, from which the flowers generally 

 spring. The old-man cactus (Polocereus senilis) is 

 so called from its resemblance to an old man's 

 head, being coveted with long white hairs. The 

 Peruvian torch-thistles (Cereus peruvianus and 

 hexagonus) are still more gigantic plants, often 

 attaining a height of forty feet, though their 

 stems be not thicker than a man's arm. The 

 rat's tail cereus (C. flagelliformis) is well known 

 from its long whip-like stems, which hang down 

 from the sides of the suspended pots in which 

 it is usually grown. The night-flowering cereus 

 (C. grandtftorus), so called from its blossoms 

 opening during night, and fading before morning, 

 has an angular, branched, and climbing stem, 

 throwing out roots at every point. The genus 

 Rhipsalis has slender jointed stems, which look 

 like samphire ; and the opuntias, which are 

 numerous and useful, are distinguished by their 

 round, flat, leaf-like bodies, united together by 

 joints, and for the most part covered with spines. 



The fruit of many of the Cactaceas is esculent, 

 but is rather insipid, having little of that acidulous 

 flavour which characterises the Currantworts, to 

 which the family is allied. It is upon the Opuntia 

 cocchtnelltfera, the Nopal plant, that the cochineal 

 insect, so valuable in the arts, chiefly feeds. In 

 the south of Europe, the prickly pear (0. corn- 

 munis) is reared as a hedge, and also for its fruit, 

 which is edible, and yields a rich carmine pig- 

 ment ; and the Indian fig (O. tuna) is grown for 

 similar purposes in Brazil. 



GROSSULARIACEVE. This is a well-known order, 

 consisting principally of one genus, Ribes, which 

 includes all the gooseberries and currants of our 

 gardens. The species, of which there are upwards 

 of eighty, are unarmed or thorny shrubs, with 

 round or irregularly angled stems and branches ; 

 simple, lobed, alternate leaves, destitute of stipules 

 and tendrils. The inflorescence is axillary and in 

 racemes. The calyx, which is often coloured, is 

 four or five cleft ; petals, perigynous, equal in 

 number to, and alternate with, the segments of the 

 calyx ; stamens, of the same number, alternate, 

 and inserted with the petals ; filaments, distinct ; 

 anthers, two-celled, bursting longitudinally ; ovary, 

 one-celled, cohering with the tube of the calyx ; 

 ovules, indefinite ; fruit, a berry, crowned with the 

 remains of the flower, one-celled, filled with pulp 

 with two parietal placentas ; seeds, numerous, sus- 

 pended among the pulp by filiform funicles ; testa, 

 externally gelatinous ; albumen, horny. 



The order is very conveniently grouped into two 

 sections namely, the Gooseberries, which have 

 prickly stems, and the flowers either singly, or in 

 clusters of not more than two or three ; and the 

 Currants, which are entirely without spines, and 

 the flowers in racemes. There are a few species, 

 such as Ribes dracantha and saxatile, which may 

 be considered as intermediate, these having the 



spines and habit of growth of the one, and the 

 racemose inflorescence of the other. The common 

 gooseberry (R. Grossularia), the red currant (R. 

 rubrum), the black currant (R. nigrum), and the 

 flowering currant (R. sanguineuin), are familiar 

 examples of the order, and all too well known to 

 require any detailed description. The gooseberry 

 is found wild in many parts of Britain ; and is 

 reared in the north of England to greater perfection 

 than in any other country. 



Gooseberries and currants have agreeable acid 

 fruits, the acidity or sweetness depending upon the 

 relative quantities of malic acid and sugar which 

 they contain. The blackberry has tonic and 

 astringent properties, infusions of the leaves being 

 used for this purpose. 



SAXlFRAGACEiE. This order consists chiefly of 

 very small herbaceous plants, with alternate or 

 opposite leaves, and is readily distinguished by 

 the peculiar ovary, which is more or less com- 

 pletely inferior, consisting of two carpels which 

 diverge at the apex. As useful plants, they are 

 unimportant, but they are the most charming that 

 greet the eye of the botanist in his mountain 

 rambles. Saxifraga stellaris and S. aizoides are 

 the great ornaments of Highland streams at a low 

 elevation ; while higher up, the rocky banks are 

 covered with a purple carpet of S. oppositifolia, or 

 the rarer S. rivularis, which attracts many a 

 botanist to the summit of Loch-na-gar. S. cernua 

 is confined to the summit of Ben Lawers. But it is 

 not alone the Scottish mountains that are adorned 

 with these 'alpine gems ;' S. Boussingaultii reaches 

 to nearly 16,000 feet on Chimborazo. 



UMBELLIFER^E. This is one of the most exten- 

 sive and important of the natural orders, compris- 

 ing about 300 genera, and above 1500 species. 





Common Hemlock : 



c, flower; d, seed. 



The genera, though presenting many minor differ- 

 ences, are, on the whole, well marked ; so that no 

 one who has seen the flower of the parsley and 

 common hemlock can have any difficulty in 

 detecting an umbelliferous plant. The species are 

 for the most part herbs, seldom shrubs, with 

 fistular furrowed stems, loving damp waste places, 

 and varying much in their properties, according 

 to the climate under which they are grown. The 

 leaves are generally divided, sometimes simple ; 

 are alternate, and clasp the stem by a broad 

 sheathing petiole. The flowers are white, pink, 



