BOLACOTRICHA. 



[ 88 ] 



BONE. 



B. nivea, Gaudichautl, yielding the fibre from 

 which Chinese grass-cloth (PI. 21. fig. 26) is 

 manufactured, is a native of China, where it 

 is largely cultivated, also in Sumatra, where 

 it is called * Caboose,' and at Pulo Penang, 

 where it is called ' Rami.' B.Puya, Wallich, 

 yields the 'Pooah' or 'Puya' fibre of Nepaul 

 and Sikkim (PI. 21. fig. 26), which has long 

 been extensively used in India, and is said to 

 equal the best European flax when properly 

 dressed ; being ordinarily roughly prepared, 

 it is dirty and bad-coloured, but makes excel- 

 lent sail-cloth and cordage. 



BiBL. Hooker, Journal of Botany, vols, 

 i. &iii. 1849-51. 



BOLACOTRICHA, Berk. & Broome.— A 

 genus of Dematiei (?) (Hy|)homycetous Fun- 

 gi), containing one species, B. grisea, found 

 growing upon dead cabbage-stalks, old mats 

 made of Typha, &c,, in tufts forming large, 

 efi'used gray patches. Messrs. Berkeley and 

 Broome express themselves doubtfully as to 

 its real affinities; in habit it approaches 

 Myxotrichum, but differs in its simple threads 

 and large spores, while the spores are not in 

 chains as in Sporodum, or minute and linear 

 as in Tricholeclionium. The threads are pale 

 purple under the microscope, strongly curved 

 at the tips like tendrils, 



BiBL. Berkeley and Broome, Ann. Nat. 

 Hist. Ser. 2. vii. p. 97. pi. 5. fig, 4. 



BOLETUS, Dill,— A genus of Polyporei 

 (Hymenomycetous Fimgi), consisting of pl- 

 icate Fungi, or ' toad-stools,' often of large 

 size, growing in woods. They have the ba- 

 sidia contained in tubes arranged perpendi- 

 cularly to the pileus and opening at its lower 

 surface ; the transverse sections of the tubu- 

 lar hymenium thus exhibit circular holes, 

 separate by double septa, each pore being 

 formed by a perfect tube; while mPolyjmrus 

 the septa are single,from the tubes being indi- 

 stinguishably blended. See Basidiospores. 



BOMBACEiE.— A subdivision of the fa- 

 mily of Dicotyledonous plants called Stercu- 

 liacese, some genera of which are called Silk- 

 cotton trees, from the long hairs which enve- 

 lope their seeds, as in the true cotton plants. 

 These hairs (from Chorisia speciosa,Bombax, 

 sp. var., Eriodendron, sp. var.) cannot be 

 spun, but are used for stuffing cushions, &c. 

 The Adansonia, or Baobab-tree, produces a 

 pulpy fruit, which contains a considerable 

 proportion of starch. The wood of some 

 kinds, as oi Bombax pentandra and Pachyra 

 {Carolinea) minor, is remarkable for its light- 

 ness and almost corky texture, residting 

 from being composed almost exclusively of 



parenchymatous cellular tissue, with scattered 

 porous ducts and true wood-cells. See Wood. 



BONE, — It need scarcely be stated that 

 bone is the hard substance serving to give 

 firmness to the bodies of the Vertebrata, to 

 protect their delicate organs, and to form 

 points of attachment for muscles. 



To the naked eye, bone appears to consist 

 of an apparently homogeneous basis, sur- 

 rounding certain cavities, areolae or cancelli; 

 these are most numerous and larger towards 

 the centre, where, in the Mammalia and Birds, 

 they form a larger cavity called the medullaiy 

 canal. This contains the marrow in the for- 

 mer class, but air in the latter. Hence we 



Fig. 64. 



e 



Magnified 90 diameters. 



Segment of the transverse section of a human meta- 

 carpal bone. «, outer surface of the bone, with the outer 

 laminae ; b, inner surface next the medullary canal, with 

 the inner luminte; c, orifices of the divided Haversian 

 canals, with their laminie ; r/, interstitial laminie ; r, la- 

 cunae, with their canaliculi. 



