164 



ACADEMIC BOTANY. 



Fin, 

 uee d 1 e - 8 h a p e d 



open, with raph- 

 idea escaping. JB, 

 rhomboidal raph- 

 ides in cells of 

 Beet (Beta). 



them, the same mineral crystallizing differently, according 



to the tissue of the plant in 

 which it is formed. These 

 crystals are called Raphides 

 (Gr. raphis, needle), on ac- 

 count of their usual shape 

 (Fig. 235, A), though they 

 are often rhomboidal (Fig. 235, B). If the 

 leaf of the Nettle Family be examined — Hop, 

 Fig, Mulberry, etc.^ — transparent spots will 

 be seen just beneath the epidermis. These 

 consist of chalky deposits, called OystolUhs, or 

 Bladder-stones. Each cystolith (Fig. 236) is 

 composed of a layer of crystals grouped 

 " around a nucleus \n) formed at the expense 

 Ka'p'hi'd'es''i'n''two of the Cell- Wall (c), which has been pulled 

 ™"1"' me^ '"eu aside, and which has lengthened into a deli- 

 cate stem (s), from which the cystolith is 

 suspended." — L. and D. The dark cells be- 

 low the dilated cell are normal cells filled 

 with chlorophyl. 



405. Phosphorescent Plants. — Many living 

 plants contain Phosphorus, which is abundant 

 in decaying organic matter. It is so comhus- 

 tible that it takes fire in the air, emitting a 

 white smoke with the smell of garlic. It shines 

 in the dark. At a temperature of 148° Fahren- 

 heit it burns with a bright flame. The crypto- 

 gams abound in it, especially the Pungi and 

 their allies, which have no chlorophyl ; yellow 

 being the color in which phosphorus is best de- sm—p rt fi 



veloped. The Olive Mushroom (Agaricus olea- dia'^kubber if. °Fiaa 

 rius), which grows at the roots of olive-trees in ehutica^: c, dibited cell 

 Italy, shines so resplendently at night that the *'"' cystolith, n; «, 

 trees are lighted by it. The Aganeus Gardneri rou"Lng"'cells".' '"'" 

 of Brazil is parasitic on the leaves of a palm, and 

 glows like heaps of red-hot coals. The Polyporus annosus in the mines 

 of Wales shines so brightly that ordinary print may be read by it. Some- 

 times the mycelium (55) is phosphorescent. Eev. M. J. Berkeley ob- 

 served a mycelium under the bark of a log of timber which made the 

 wood glow with a light like white heat, and which shone through 

 five folds of paper. jPhanerogams are also phosphorescent. The yel- 

 low lilies contain pho.sphorus. The Screw Pine is phosphorescent, 

 especially at flowering-time ; when the spatha bursts it emits flashes 

 like miniature lightning, and which are considered electrical. Phos- 

 phorescence usually appears in the inflorescence, both in cryptogams 



