690 



APPENDIS. 



fronds, about two feet long and one foot broad, having 

 a round stipes, or footstalk, with a channel or groove 

 along the upper side. The piunre are nearly opposite, 

 shortly petiolate, and oblong acuminate, with a ser- 

 rated margin and simply forked veins. 



PLATE XIV. 

 Cacti. 



Fig. 1. — Opnniia Brasiliensis, a native of Brazil, 

 belongs to a group of Cacti to which the name of 

 ' ' Prickly pear " has been given, from their fruit being 

 pear-shaped, and having smaU tufts of short spines 

 upon their sui-face. This species has a straight, round, 

 woody stem, which attains to the height of thirty or 

 forty feet and upwards, becoming gradually atte- 

 nuated towards the top, and armed with numerous 

 fascicles of long spines, which are very strong, sharp, 

 and ash-coloured. It is furnished with a number of 

 almost horizontal branches, which gradually become 

 shorter towards the top, giving it a pyramidal ap- 

 pearance. The flowers are produced in great abun- 

 dance, chiefly from the prominent parts of the mar- 

 gins of joints. When fully expanded, they are about 

 an ihch and a half in diameter, and of a bright le- 

 mon coloiir. The fruit is oval or pear-shaped, about 

 an inch and a half in diameter, and slightly hollow 

 at the apex. Its skin is thin, smooth, of a shining 

 pale yellow colour. It is almost impossible to handle 

 the fruit without getting the skin full of bristles, 

 which break oflf and leave a fragment behind. Ow- 

 ing to the bristles with which the skin is armed, it 

 is seldom used as a dessert fruit ; althougb the fruit 

 of Opuntia vulgaris, a closely allied species, which is 

 cultivated in the south of Europe, is much esteemed 

 as a dessert fruit, and large quantities of it are con- 

 sumed, especially in some parts of Spain. 



Fig. 2. — Oa-eus senilis, the "Old mah Cactus," is 

 a native of the hottest parts of Mexico ; it grows to 

 about twenty or twenty-five feet high, and nine or 

 ten inches in diameter at the broadest part. Its 

 stem contains an extraordinaiy quantity of oxalate 

 of lime in small sand-like grains, which renders it 

 very heavy and brittle ; portions of the dried tissue 

 have been analyzed and found to contain from sixty 

 to eighty per cent, of this substance. The surface of 

 the stem is of a grayish green colour, and is divided 

 into thirty or forty narrow furrows, which are about 

 half an inch deep, and have very acute sinuses ; the 

 ridges are obtuse, rounded, and furnished with elon- 

 gated areoles, seated on small tubercles, from which 

 proceed three or four long white spines, smTOunded 

 by a thick mass of very long, wiry, white or gray hair, 

 from which circumstance the plant is commonly called 

 the "Old man Cactus." The flowers of this plant 

 have never, to our knowledge, been produced in 

 Europe. 



Figs. 3 and 10. — Opimtia cochinUlifera (the Cochi- 

 neal-insect Cactus) is a native of Mexico, but it is 

 cultivated in the West Indian islands and other 

 places. (See p. 365.) 



Two kinds of cochineal are distinguished in com- 

 merce. One sort is called Orana fina by the Spa- 

 niards, the other Grana syhestre. The colouring 



matter of the first sort is of a finer quality and in 

 greater abundance than in the latter ; and the sub- 

 stance which envelopes the insect is pulverulent or 

 powdery in the former, whilst in the latter it is floc- 

 culent or cottony ; but it has not yet been determined 

 whether they are different species of Coccus, or whe- 

 ther the differences do not depend upon the species 

 of Opuntia used, or the method of cultuie adopted. 



Fig. 4. — Echinocactus Staincsii, anative of Mexico, 

 growing abundantly at San Luis Potosi. The stem 

 is somewhat elliptical, and about five or six feet high, 

 and one to two feet in diameter ; it is slightly woolly 

 at the top, of a deep green colour, and has from seven- 

 teen to twenty furrows. The flowers are produced 

 on the top of the plant. 



Fig. 6. — Cevcus cosrulescens is a native of Brazil, 

 and has an angular glaucous blue coloured stem, ris- 

 ing perpendicularly to the height of fifteen or twenty 

 feet, with a diameter of three or four inches in the 

 broadest part, slightly attenuated towards the base. 

 It is divided into eight or ten furrows, with a corre- 

 sponding number of obtuse, wavy ridges. The flowers 

 of this plant gi'ow from one of the areoles towards 

 the top of the plant, and are very nearly as large and 

 beautiful as those of Cerexis grandijlorus, the "Night- 

 flowering Cereus." 



Fig. 6. — Echinocactus visnaga grows to a large 

 size ; two gigantic specimens of it were sent to the 

 Eoyal Botanic Garden at Kew some years ago, from 

 San Luis Potosi, but both have since died; one of 

 them weighed 713 pounds, and measured four feet 

 and a half in height, and about two feet nine inches 

 in diameter ; the other was still larger, weighing one 

 ton, and being nine feet in height, with a diameter of 

 more than three feet; but these are said to have been 

 small plants in comparison with others growing in 

 their native country. In shape this species is some- 

 what elliptical, and has forty or fifty deep, narrow 

 furrows, with the same number of wavy, sharp-edged 

 ridges ; the furrows are of a glaucous green colour, 

 becoming lighter towards the top of the ridges, and 

 the centre of its summit is covered with a dense mass 

 of a short, tawny, wool-like substance. The flowers 

 are produced singly, from amongst the dense woolly 

 substance at the top of the plant ; they have nume- 

 rous serrated petals of an oblong or spathulate form, 

 and a shining yellow colour. 



The specific name of visnaga has been given to 

 this plant, in allusion to the use to which the Mexi- 

 cans apply the spines, viz., for making toothpicks, 

 visnaga or visnaga signifying in Spanish toothpick. 

 It has been calculated that the number of spines on 

 the largest plant of this species sent to Kew Gardens, 

 could not have been less than 51,000 ! 



Fig. 7. — Cereus hexagonus, a native of Surinam 

 and other hot parts of South America, where it at- 

 tains the height of forty feet and upwards, seldom 

 having any branches; its stem has usually six angles, 

 or sometimes more, with very wide furrows. The 

 flowers are produced from the angles of the stem near 

 the top of the plant, and have a tube about six inches 

 long, with imbricated greenish sepals, and petals 

 which are reddish outside and white within; the 



