70 



ALDER- TREE ALECTO RID /E. 



tral axis ; they are of various shapes, having the aj)- 

 pearance of a thick, porous, or cellular mass, spread 

 out or ramified, sometimes lobed, and at others in the 

 form of a crust ; the interior substance spongy, or 

 like cork, surrounded by a radiated, tubulous tegu- 

 ment, and enclosed in a hard leathery rind. 



The cells of this polypidom are round, of various 

 diameters, from the eighth to the fifth of an inch, se- 

 parated from each other by thin partitions, rendered 

 opaque by a great quantity of solid globules, that 

 appear to form the least animated part of the zoophyte. 

 Each cell encloses a polypus, composed externally of 

 a transparent sac or membrane, strengthened by 

 eight filiform longitudinal fibrous bands, placed at 

 equal distances, and difficult to be perceived, owing 

 to the presence of numerous transverse and parallel 

 fibres. The longitudinal fibres seem attached to the 

 borders of the cells and to the roots of the tentacula. 

 The sac (which is capable of extending and contracting, 

 the upper part falling back when the little animal 

 retires within its transparent covering) encloses the 

 body of the polypus, having in the centre a hemi- 

 spheric mass, divided into eight equal parts by vertical 

 partitions, whose summits present a round or lozenge- 

 shaped opening, at the will of the animal, which 

 probably forms the mouth ; the borders are furnished 

 with irritable appendages, the form of which it is 

 difficult to distinguish. The tentacula fold over 

 each other, and surround the globular mass, which 

 then forms a spherical or pyramidal body. 



The general envelope of the polypus rises a small 

 way above the surface of the polypidom, and all the 

 parts it encloses are easily observed with a good 

 lens. The complicated organisation of the alcyonian 

 polypi renders any description of them extremely 

 difficult ; many points of resemblance seem, how- 

 ever, to unite them to the animals of the harder poly- 

 pidoms. This class varies much in the size of its 

 species, some of them extend in patches of greater 

 or less thickness on the surface of the bodies to 

 which they adhere, whilst others raise their branches 

 to the height of several feet. Some live on marine 

 plants ; others delight more in muddy waters, raising 

 their animated tubercles above its surface ; but the 

 greater number attach themselves to rocks and the 

 larger shells, which they sometimes cover with their 

 polypean mass. They are found' in all seas and at 

 all depths ; but from the difficulty attending re- 

 searches into the nature and habits of these creatures, 

 only about fifty species have been distinguished, 

 forming probably but a very inconsiderable portion 

 of the number existing. 



This genus is frequently found in a fossil state, 

 and the species are far more numerous than those dis- 

 covered in a recent state. 



ALDER-TREE. A genus of forest trees, indi- 

 genous to Britain. Belonging to the Linnasan 

 class and order, Moncscla Tetrandria. Natural 

 order, Amcntncece. Generic character : male flower 

 receptacle of the ament wedge-shaped, truncated, 

 composed of three flowers ; calyx, scaly ; corolla, 

 four-parted ; stamina, four-female flowers ; calyx, 

 scaly, or two flowered ; corolla, none ; seed, com- 

 pressed, oval, naked. The alder affects moist bog 

 earthy soil on the banks of rivers or water-courses, 

 Its natural habit of growth is to run up with a plu- 

 rality of stems ; and when trained with one, though 

 it forms rather a handsome tree, it is not long-lifed. 

 They are much more valuable as underwood than 



grown for timber, being, like the willow, more vigor- 

 ous for being cut down ; that is, the roots are more 

 active in yielding supplies to young shoots than to 

 old stems. Alder poles are much used by turners 

 and other small ware artisans ; also by charcoal 

 burners for the manufacture of gunpowder ; and when 

 butts of good size, and sound throughout, can be 

 obtained, this timber is highly valued for piling and 

 planking to lie constantly under water. The bark in 

 some countries is used for tanning, and some quality 

 used in dyeing is extracted from the young twigs. 

 Of the fourteen species, the heart-leaved, the long- 

 leaved, the red, and the saw-leaved, are fit for the 

 arboretum ; and among the varieties of the common 

 one, the fringed-leavcd, cut-leaved, and oak-leaved, 



The Alder Tree. 



arc ornamental. The common species are raised 

 from the seed sowed on a moist soil in autumn. The 

 curious varieties are propagated by layering some- 

 times by grafting on the common. 



ALDROVANDA (Decandolle). An Italian 

 aquatic perennial, sometimes seen in British botanical 

 collections. Linnsean class and order, Pentandria Pen- 

 lagynia. Natural order, Drosceracece. Generic cha- 

 racter : calyx, five cleft ; corolla, of five petals ; 

 stamina five; ovarium is surmounted by five styles 

 and stigmas. Fruit, a capsule of one place, containing 

 ten seeds, which are discharged from five valves. 



ALECTORID^;, so called from that Greek 

 name cf the cock which describes him as the caller of 

 people from their beds a character in which he has 

 been equally a favourite with peasants and poets in 

 all ages, a family of birds belonging to the order 

 gallimdcs, or poultry. They are all natives of Ame- 

 rica, and dwellers in the forests of that country, large 

 birds, and in their appearance and habits bearing a 

 considerable resemblance to turkeys. They all have 

 the wings short, broad, and hollow, the tail rounded, 

 composed of strong feathers, which can be spread 

 out as rays in a wheel. Many of them have naked 

 skins or callosities at the base of the bill, especially 

 in the males ; and some have flexures in the wind- 



