AN ENCYCLOPAEDIA OF HORTICULTURE. 



373 



Mitchella continued. 



to six-toothed, persistent; corolla fannel- shaped; throat 

 bearded; limb three to six-lobed, bearded within, re- 

 curved, valvate. Fruit scarlet. Leaves opposite, shortly 

 petiolate, ovate-rotundate ; stipules intrapetiolar, minute. 

 M. repens, the species introduced to cultivation, is a 

 pretty little plant for rockeries, hardy ferneries, and such 

 like places. Propagated by division of the roots. 



M. repens (creeping).* ft. white, tinged with purple, usually two 

 together on the top of each peduncle, fragrant. Summer. 

 I. small, opposite, roundish-ovate, smooth, shining, often varie- 

 gated with whitish lines. North America, 1761. (L. B. C. 979.) 



MITEL LA (a diminutive from mitra, a mitre or cap ; 

 alluding to the form of the young pod). Including Drum- 

 mondia. OBD. Saxifrages. A genus consisting of five 

 species of hardy perennial herbs, natives of North America 

 and North-eastern Asia, only two of which have been 

 introduced. Flowers greenish, small, distant, often secund 

 or nodding, in slender many-flowered racemes ; scape 

 slender, erect, naked, or one or two-leaved. Leaves 

 long-stalked, cordate, lobed or crenated. The species 

 thrive in any light soil, but do best if grown in peat. 

 Propagated by divisions. M. diphylla is a pretty plant 

 for the rockery. Both the species here described are 

 from North America. 



M. diphylla (two-leaved), fi. white, with pinnatifldly fringed 

 petals. April. L, radical ones cordate, somewhat three to n've- 



lobed, dentately serrated, on long petioles; cauline ones two, 

 ite, smaller, and nearly sessile, 



, 

 h. 6in. to 9in. 1731. 



(B. R. 166.) 



M. pentandra (five-anthered).* fl. yellowish ; petals five, pecti- 

 nately pinnatifid, alternating with the sepals; scape leafless. 

 May. L, radical ones on long petioles, cordate, bluntly lobed. 

 h. 6in. 1827. SYN. Drummondia mitelloides. (B. M. 2933.) 



MITES. These form a group of animals related to 

 the true Spiders, but differing from them in their very 

 small size, and in having the abdomen closely united 

 with the front part of the body, instead of being joined 

 to it by a narrow stalk. Most Mites have six jointed 

 legs when young, and eight when full-grown; though in 

 a good many the posterior pairs are very small and 

 useless, or may not be present. One group, the Phytopti, 

 or Gall Mites, so far as known, have never more than 

 two pairs of very short legs, on the lower surface of 

 the body, in front. All the true Mites are so small as 

 to render the microscope indispensable in examining 

 them ; but, despite their small size, they form an im- 

 portant order of animals, because of their abundance 

 and habits. Many species live on dead or decaying 

 organic matter ; others exist as parasites on living 

 animals, especially on insects ; and those belonging to 

 Tetranychidce and Phytoptidas are parasites on living 

 plants, and therefore deserve somewhat fuller mention 

 here. The species parasitic on animals may be regarded 

 as mostly useful, since they feed largely on insects; 

 but among them are one or two that are, at certain 

 seasons, very troublesome to gardeners, fruit-pickers, 

 and others. The best known of these is the Harvest 

 Bug (Tetranychus, or Leptus autumnalis), which is of a 

 brick-red colour, and so minnte as to be invisible to the 

 naked eye, and which swarms upon bushes and vegetables 

 in the garden, as well as in hay and stubble fields. 

 They feed ordinarily on plant juices, but very readily 

 attack the human skin, especially the skin of women and 

 children ; and they are also very troublesome to domestic 

 animals. Wherever a Mite has fixed on the skin, it 

 causes a hard swelling of a red colour, and the place 

 bitten continues to itch greatly for some time. Mites 

 are more abundant during late summer and autumn. 

 They attack some people very severely, others hardly 

 at all. Eemedies are as follows : Washing the parts 

 bitten with weak spirits will often prove serviceable in 

 reducing the itching. Sulphur ointment, solution of 

 carbolic acid, and benzine, have also been used, and have 

 been found to give relief. The true Itch Mite (Sar- 



Mites continued. 



coptes scdbiei) is sometimes very annoying, as it causes 

 intense itching at the wrists and knuckles, where it 

 burrows under the skin. The disease is propagated by 

 contact of healthy with diseased hands, directly, or by 

 handling the same things. It is easily got rid of by 

 personal cleanliness and the use of sulphur ointment. 



The Plant Mites belong to the two families Tetrany- 

 chidce and Phytoptidas. The former group includes 

 eight-legged Mites, which live on leaves and twigs, suck 

 the juices, and often greatly injure the plants thereby. 

 They are usually minute, semi-transparent, and some 

 shade of white, yellow, or pale brick-red. They spin 

 a web on the backs of the leaves. The latter become 

 discoloured, and turn yellowish or grey above, shining 

 dirty-white below. Garden and greenhouse plants often 

 suffer much from their attacks. They are best com- 

 bated by applications of soft soap and sulphur. Quassia 

 solutions may also be used. See also Red Spider. 



The Phytoptidas, or Gall Mites, have long, slender, 

 nearly colourless bodies, and are easily known by their 

 form, their having two pairs of very short legs near the 

 head, and their habit of forming galls on plants. The 

 Mites are very numerous, but are too small and too 

 similar to be easily distinguished; hence, the galls must 

 be employed to recognise the kind of Mites that 

 made them. Cultivated trees and herbs seldom suffer 

 much from the galls on them, so that it is needless here 

 to mention more than the chief forms. These are : 1. The 

 Erineum galls, in the form of patches of velvety hairs 

 on the lower (rarely upper) surface of the leaves ; these 

 patches pass from white into rusty-brown. They were 

 at one time described as fungi. Examples occur on 

 Apple, Maple, Birch, Beech, &c. 2. Inrolled leaf- 

 margins, with thickened and discoloured tissues, such 

 as may often be seen on leaves of Hawthorn. 3. Blistered 

 spots in the leaves ; these spots become brown or black, 

 and are then very conspicuous. Pear leaves are, at 

 times, very much injured in this way ; and Elm leaves 

 are yet more frequently infested, though the injury done 

 to them is less. On a careful examination, there is found 

 to be a small hole on the lower surface, about the middle 

 of each discoloured spot, giving passage to the Mites 

 to and from the interior of the leaf. 4. Wart, or Nail 

 Galls, consist of outgrowths from the upper surface of 

 leaves, like warts, about the size of pin-heads, or like 

 small nails, reaching in. long, and are abundant on Lime, 

 Maple, Willow, and many other trees and shrubs; but, 

 beyond their unsightliness, they usually do little harm 

 to the plants. 5. Bud Galls are buds caused to swell 

 greatly, but to remain unopened, or to form only sickly 

 branches ; or, if this continues for some years, it may 

 give rise to knots of diseased branches. The Mites live 

 between the scales of the buds. Much harm is done in 

 this way to Black Currant bushes in some places, and 

 also to Hazel and to Birch. 6. The flower - buds are 

 injured, and become green, and the parts of the flowers 

 are often replaced by green structures, as in reversions 

 to the leaf -type. Campanulas, and a few other cul- 

 tivated subjects, are liable to this change ; but it is more 

 frequent in some wild plants ; e.g., in the genus Galium, 

 or the Bedstraws. Yet other forms of Mite Galls might 

 be noted, but they are of no practical moment to gar- 

 deners. 



It is impossible to reach the Mites, protected as they 

 are in their galls. As a rule, the species that gall the 

 leaves do little practical mischief; but those that gall 

 the buds so spoil the appearance of some plants as to 

 render their destruction desirable. The only certain 

 method is to collect the plants that bear the young 

 galls, and destroy them before the exit of the Mites. 

 Plants (e.g., Currants) badly affected with Bud Galls 

 should be uprooted and burned, and the ground allowed to 

 remain clear of the same plants for a year or two at least. 



