496 



THE DICTIONARY OF GARDENING, 



Oniscidte continued. 



the soft internal organs ; these rings are united by 

 soft membranes, to permit of the motion of one ring 

 or another. They resemble insects considerably in the 

 strnctnre of the mouth, antennae, and limbs; but they 

 are readily distinguished from insects by possessing more 

 than three pairs of true jointed legs, and by breathing 

 by gills instead of by air-tubes. They never have a 

 trace of wings ; and their general appearance is an easy 

 means of recognising them. They have two pairs of 

 antennae, though, in Oniscidce, one pair is hardly to be 

 seen. Their course of development also, and the changes 

 passed through, are different from those undergone by 

 insects. The class Crustacea includes a number of 

 families of very different appearance, size, and habits ; but 

 most of its members live in water, and those which live 

 out of water prefer moist situations, such as among dead 

 leaves and other decaying matter, and conceal them- 

 selves, accordingly, during the day, in holes, from which 

 they emerge, to feed, at night. The larger Crustacea, 

 or Podophthalma, have their eyes supported on stalks. 

 To this series belong crabs, lobsters, shrimps, and allied 

 forms. By far the greater number of species of Crus- 

 tacea, however, are small, with the eyes sessile, i.e., upon 

 the surface of the head, not on footstalks. The indi- 

 viduals of several of the groups in this series are 

 microscopic in size; but two groups contain species of 

 iHn. and upwards in length, having the head and seg- 

 ments of the body all distinct, with the body segments 

 all alike in general form and possessing fourteen pairs 

 of legs. Of these two groups, one, called Amphipoda, 

 has the front pairs of legs different from the hinder 

 ones. The other group, called Isopoda (meaning equal 

 feet), has the legs all similar, and possesses certain ap- 

 pendages at the hinder end of the body connected with 

 breathing. To this group belong the Oniscida. 



The Oniscidce, are distinguished from the remaining 

 Isopoda by their habit of living in damp air instead of 

 in water; by the organs for breathing being modified 

 into functional lungs, instead of being fitted to obtain 

 oxygen from water ; and by having only one pair of 

 antennae well developed, and the legs fitted only for 

 walking or crawling. They are mostly oblong or oval 

 in general outline, and much depressed, with broad, short 

 segments on the back, nearly hiding the rather short 

 legs; but the antennae are distinctly seen, projecting from 

 the sides of the head. The females carry the eggs 

 and young, for a time, in a kind of pouch on the lower 

 surface of the body. The young differ from the old 

 animals only in the smaller number of body rings and 

 legs. The Oniscidce are mostly sluggish, and live, during 

 the day, in holes or other places of concealment. In 

 colour, they are usually greyish-brown or dark slaty-blue, 

 sometimes spotted with yellowish or buff markings on 

 the back. They are common in damp, dark places, e.g., 

 under stones and dead leaves, in holes in walls or trees, 

 in flower-pots, in cellars, &c., frequently crowded to- 

 gether in large numbers. They feed on plants, usually 

 preferring decayed parts, but often do injury to deli- 

 cate flowers (e.g., Orchids), and frequently eat down 

 seedlings, or destroy plants that spread their leaves on 

 the soil, by eating into the part where root and stem 

 meet. They are injurious to fruit - trees growing on 

 walls, by eating into the ripe fruit that can be reached 

 from the wall ; and, in like manner, they eat into fallen 

 fruits. It may be observed, that they are the only 

 Crustacea at all hurtful in gardens. The most trouble- 

 some species are three, nearly the same size, viz.. about 

 tin. long on an average. These three are Oniscus 

 asellus, with eight-jointed antennae, back nearly smooth, 

 light greyish-brown or leaden-blue, with two rows of 

 yellowish or buff spots near the sides, and others 

 scattered over the middle space of the back; Porcellio 

 f caber, with seven-jointed antennas, back covered with 



Oniscidsa continued. 



round, raised tubercles, dark grey or slaty-blue, and often 

 spotted as in the last but varying considerably in colour ; 

 and Armadillo vulgaris, easily known by its form being 

 longer, and more convex, with the sides nearly parallel; 

 by the absence of projecting appendages at the tail ; by 

 its seven-jointed antennae, and uniformly dark leaden 

 colour; but, above all, by its habit of rolling itself up 

 into a ball when alarmed. This habit has gained for it 

 the name of Pill Millipede, and, probably, was the ground 

 on which it was, in past times, employed as a medicine, 

 to be swallowed as a pill. It was much praised as an 

 effective remedy in a number of ailments, but has fallen 

 out of repute. Oniscus asellus was also at one time used 

 as a remedy for ague, consumption, and other diseases ; 

 but it also has been discarded. 



Prevention. All holes and coverts ought to be to the 

 utmost got rid of, to prevent the Woodlice fiom finding 

 shelter in the neighbourhood of the plants that have to 

 bo protected. Further security may be obtained by 

 putting the pots on stands in water, or suspending them ; 

 or, in some cases, by covering them with glass. Trees 

 may be protected by closing all holes in walls, removing 

 loose plaster, and putting a strip of tar, or other adhesive 

 substance, along the base of the wall, and on the trunks 

 of the trees. 



Remedies. When plants are injured, the cause should 

 be sought for, and the animals destroyed. Traps may be 

 used successfully, such as slices of fruits or fleshy vege- 

 tables, laid in favourite retreats; or hollow stems, and 

 other shelters, placed in the localities frequented by such 

 animals. Such traps should be examined from time to 

 time, and the Woodlice found therein destroyed by 

 being crushed, or dropped into boiling water. 



ONISCUS. See Oniscidse. 



ONOBROMA, of De Candolle. Included tinder 

 Carthamus. 



ONOBROMA, of Gaertner. A synonym of Car- 

 dnncellns (which see). 



ONOBRYCHIS (the old Greek name used by 

 Dioscorides, derived from ones, the ass, and brycho, to 

 bray; said to be the favourite food of the ass, who 

 brayed in his eagerness to get at it). Saintfoin. OBD. 

 LeguminostK. A rather large genus of greenhouse or 

 hardy, unarmed herbs or sub-shrubs, or rarely very spiny 

 small shrubs. Upwards of seventy species have been 

 described, not more than fifty of which are really dis- 

 tinct as such ; they inhabit Europe, North Africa, and 

 extra-tropical, mostly Western, Asia. Flowers purplish, 

 pink, or white, disposed in axillary pedunculate spikes 

 or racemes. Pods compressed, semi-orbiculate or orbi- 

 culate-circinate. Leaves impari-pinnate ; leaflets entire, 

 exstipellate. The plants are of easy culture in a deep 

 sandy-loam soil. Seeds should be sown, in spring, in 

 their permanent quarters. The only species calling for 

 mention here are the following; they are hardy peren- 

 nial herbs. 



O. Capnt-galli (cock's-head). A. flesh-colour, in few-flowered 

 spikes. July. Pod slightly pubescent. I. oblong or cuneate- 

 obovate, mucronate, pubescent. Stem erect or diffuse, h. lift. 

 South Europe, 1731. (S. F. G. 723, under name of HeJysarum 

 Caput-palli.) 



O. radiata (rayed), ft. yellowish-white, lined with red, and 

 spotted with yellow on the standard ; calyx (and pod) villous ; 

 spikes cylindrical. June. i. ovate, obtuse, mucronate, hairy 

 beneath. Stem erect, softly hispid, h. lift. Iberia, 1818. 

 (B. R. 1847, 37.) 



O. sattva (cultivated). Common Saintfoin. fl. variegated, on 

 elongated spikes. Summer. Pod pubescent. I., leaflets elliptic- 

 oblong, mucronate. Stem erect, h. 2ft. to 3ft. West and South 

 Europe (Britain), North Asia. (J. F. A. 352; Sy. En. B. 381.) 

 O. 8. montana (mountain). It. purplish-rose, on short spikes ; 

 keel longer than the vexillum. Summer. Pod denticulate at 



iback. i. cuneate-lanceolate, mucronulate. Alps of Europe, 

 1817. A very pretty and rather decumbent - growing rock 

 plant 



