284 



THE TROPICAL AGRICULTURIST. 



[Oct. 1, 1886. 



eral matters required for the development of the 

 plant — and which can convey during a season of 120 

 days, a total of two-thirds of an ounce per plant — 

 this is in the ratio of 2 grammes of mineral food 

 for the formation of one gramme of sugar. ?>[. Girard 

 demonstrates that the formiiii.m of the sugar takes 

 place in the. aerial part of the x''ant, that is to say, 

 through the medium of the leaves ; that it is in the veins 

 of the leaves, not in the stalks, and under the direct 

 action of light, that the saccharine phenomena take 

 place. Supposmg a tuft of leaves to weigh 20 ounces, 

 and these represent 66 per cent of stalks and 33 per 

 cent of veins ; and that the latter contains 2 gram- 

 mes of saccharine matter during the day, of which the 

 half disappears during the night, the bulb can thus 

 receive daily oiie gramme of formed sugar, pending 

 100 days. One hundred grammes, over ;3 ounces of 

 sugar, is thus stored up, which means for a root 

 weighing 26 ounces, a richness of 13 per cent. 



About twelve years ago clover was attacked by a 

 parasitic fungi which seemed to cut the stem close 

 10 the surface of the soil, when the stalk blackened 

 and the leaves yellowed. It is complained that 

 Jacerne presents simiL.r symptoms in the east of France, 

 and is more general where rye is cultivated. Could 

 it bo ergot;-' And are vegetable diseases contagious ? 



THE CACTI OK "PEICKLY PEAES " OF 



SOUTHERN INDIA 

 are thus noticed in the proceedings of the Agri- 

 Horticultural Society of Madras: — 



Read the following extract from a letter from the 

 Honorary Secretary, dated Madras, 23rd June 18S6, 

 to the Director, Royal Gardens, Kew:— 



" Your reference to the Vactacece brings me naturally 

 to a subject which has been interesting me greatly 

 for some tiTue. Dr. Bonavia wrote to this Government 

 some time ago, and advised the introduction of " the 

 prickly pear " of Malta and that it should be grafted on 

 "the prickly pear" of India. In previous years, 

 suggestions had been made by others, to get rid of 

 prickly pear, which intrudes ou cultivable land, by 

 the introduction 01 the Cochineal insect to eat it ; 

 while many attempts have been made to introduce 

 Cochineal for its own value. In some cases it was 

 asserted that the prickly pear was so and so, and 

 " varieties " were spoken of by writers who should 

 have known better, so when Dr. Bonavia's letter was 

 referred to me, I set to work to study the subject. 

 I first satisfied myself that most writirs and author- 

 ities spetik of Ojjinitia Di/lcnii as, or as if it was 

 the prickly pear of India, or at least the only one 

 of any importance, See Hooker's Flora of British 

 India., Roxburgh Flora ludica, \\ ight and Aruott 

 Prod , p. 363, Wight's Illubtrations, fig. 114, and 

 innumerable i'roceedmgs of the Government of Madras, 

 the Board of Revenue, Madra*, and this Society. '' I 

 knew we had alout a dozen .species in the Gardens, 

 and I knew where to iind clump.-< of at !e»st four species 

 wild and used as hedge plants iu MMdras; but being 

 Lere in the last hot sea.son when the plants flower 

 most abuiidPiitiv, I undertook a^criesof long rides to 

 hsfpect a!l thickets of piichly piar of which I Knew 

 or heard) 10 tt IT) mile? *'roni tb-.-u Gnrdeus in all 

 dirtc'itnr^- "I found atoHceThit the spedis, which 

 appri'priates Whole fields and riilHtc >'te8 near Madras, 

 is not U. Vdlenu, that 0. Di"cirii is comparatively 

 rare and that there is a third distinct species nearly 

 as common as 0. DilUnii. •' I have little doubt 

 that the plint in and round Ma'h-as is O. spinosiimiw 

 Haw. meiitionid in Brown's Hand-book of tree?, 



&c., in Madras, Voigt's Hort. 



Sub 



Cal. p. 62, Dons. 



Miller's Garden* rs Dictionary, Vol III, p. 172 and 

 Gri.-^ebach's V>'. Ind. Fl. p. 302. It is a very distinct 

 plant. It grows c-frt ten to fi teen feet, often assum- 

 ing (luito a trct-like character, wiih a thick woody 

 sfteuii Its colour is blue green. I;s long (jrei/ spines 

 are very imn.erous, and they and t'le small thorns 

 hUrrouiu'ling them so tasily detached that they stick 

 and work mto every thing that touches them. The 

 flower before it opens is a beautiful rose colour, when 

 fully opdi almost orange from the quantity of yellow 

 i.iteriujngled. The fruit is oval; pulp very rich ii) 



colour and probably sweet, aa though thickly studded 

 with thorns, birds and beasts eat it greedily. 



"What I take to be the true 0. Dillenii though 

 not in all particulars agreeing with the figure in Wight's 

 Illustrations, Vol. 2, is over the considerable tract 

 of country through which I have specially looked 

 for it, comparatively rare -probably not found once 

 for the other's hundred. It is a prostrate shrub, 

 rarely struggling up four or five feet by resting its 

 upper branches on those below. Its colour is pale 

 or J>rif/ht green. " \\'here clumps of the two species 

 stand out on a bare plaiu,r side by side, as I have 

 found them, you cau tell which is which, a couple 

 of hundred yards off by the colour as well as by their 

 different habits of growth. Its thorns are far less 

 numerous, two or three in each cluster, yellow and 

 genei-ally curved. The flowers before they expand 

 are straw-coloured, when open the mo.st excpusite 

 and intensest, clear, bright yellow. The fruit is nearly 

 the shape of a jargonelle pear, and usually eaten 

 by animals before it is ripe. The shape of the fruit 

 is well shown ia Wight's plate. '■ The third species 

 is rarer than the last; in colour and habit of growth 

 it is similar, but perhaps its green is brighter, and 

 I think I have seen it grow higher. It grows in 

 the hedges in Madras; but I have found it outside 

 15 miles from these Garden.":, and far from native 

 houses or cultivation, where there could have been 

 no object in planting it, so it probably grew from 

 seed. The thorns are few, growing generally giiujle, 

 and (/re;/; the unopened flowers are ro.sy; when open, 

 yellow, streaked or suffused with ro.se. The fruit is 

 somewhat the shape of a swan egg pear. " The 

 flowers and fruits of the three species are about 

 the same size and the pulp of fruits much the 

 same colour, " We have unfortunately no work yet 

 in our Library which enables us to identify the plants 

 here, so a^e sending you in a box, specimens numbered 

 iu the above order — fiowers of each carefully dried 

 in !-aud, and a branch or two of each which will, 

 I hope, reach you iu good enough order to grow 

 if the matter interests you. We sent you seed of 

 the first two some mouths ago. 



" Several of the species we have in the Gardens 

 do not Hower, including a spineless one (possibly 

 degenerate O. Cochliiellifera) which is not uncommon 

 in Madras, but we are making a new rock-work in 

 a sunny corner for them and hope to iudentify 

 them all in time," 



Read the following extract from letter, from the 

 Honorary Secretary, dated Sth February 1886, to 

 W. T. Thiselton Dyer, Director, Royal (Jardens, Kew: — 

 "I was amongst the Prickly Pear again yesterday, 

 and find my account of the fruit not quite accurate. 

 No. 1, 0. xpinogissima gets purple all over and has 

 pulp of the deepest of purple magenta or scarlet; 

 No. 2, O. ]>illenii. the fruit, from many opened 

 yesterday, is often ripe when quite green outside, and 

 usually seems to have only a pink or ro.sy cheek, 

 while the rii'-p is the same rich colour, bard to des- 

 eri:,, — pu!].|f ^ca^let; No. 3, which I think must be 

 0, Cochlnd ifera degenerate, has •.■nmetime.s a i>iuk 

 cheek, but seems to be u.^ually ycliow, «itb ^Tccn 

 pulp I vas surprised by this, and felt inther con« 

 Kised over i^ iH to how I before concliHcl the pulp 

 was purple. I could not find a good ripe fruit yester- 

 day, but ordered a look out for one for me. "There 

 is a very striking difference in the unopeu flower 

 buds of Nos. 2 and 3. '• Yesterday I found flowers 

 of No. 2. sireaked aad strained with crimson or 

 rose, nearly as much as those of No. 3." 



Ren 1 the fol'owing extract from a letter, from 

 W. T. Thiselton Dyer, Esq., dated Kew, 31st M;irch 

 1886, in reply:— I have your letters of J.auuary 23 

 and VehruJiry 8. The box of Opuiitia specimens has 

 arrived in good order. "My colbague. Professor 

 Oliver has been so good as to report upon them. 

 He says that they are plants of unusual diiiicu'ty 

 from the muddle in their literature. He ide)itifies 

 your No. 1, as <). im/ricaii.s. Haw.— very nearly allied 

 to O. Tuna {—Cactiu Tuna, L,) and to Ekttior, 

 Mill. ; No. 2. is O. Dillenii, Haw. ; No. 3. is ('. 

 mon'ocantha, Haw. {—Cactus indici'.g, Iloxb,). You will 



