PEN1CILLIUM. 



[ 585 ] 



PEPPER. 



many years ago, by Tin-pin, that P. glaueum 

 is the last term of the growth both of the 

 true yeast-plant (Torula Cerevisice) and of 

 the milk-yeast (Oidium lactis). We have 

 found the gelatinous crusts of the vinegar- 

 plant to contain structures which represent 

 Torula and Oidium, and to grow like them ; 

 and we have also observed, in repeated ex- 

 periments, that beer allowed to stand until 

 sour, at first appears clothed with a whitish 

 mealy collection of minute vesicles, repre- 

 senting the ultimate stage of Torula, and 

 subsequently this gradually gave place to 

 gelatinous matter, which at length covered 

 the whole surface with a tough film, and 

 fruited as Penicillium glaueum. Hence it 

 would appear that the yeast-fungus also 

 is merely a vegetative form of Penicillium 

 developed under peculiar conditions. This, 

 however, has been actually proved by 

 Berkeley and Hoffman (see " Yeast," in 

 Black's { Encyclopedia of Agriculture'). 

 More is said on this point under VINEGAR- 

 PLANT and YEAST. 



One of the species has become famous on 

 account of its extremely rapid occurrence 

 in Paris on the u pain de munition," where 

 the spores must have undergone a degree of 

 heat equal to that of boiling water. 



Several species are enumerated j and we 

 have given under the separate head of 

 COREMIUM a form which is merely a con- 

 fluent growth of Penicillium, producing a 

 compound pedicel. 



P. glaueum, Grev. Mycelial filaments 

 form a crust-like web, spores green or 

 bluish. Greville, Sc. Crypt. Fl. pi. 58. fig. 1. 

 P. crustaceum, Fries. Extremely com- 

 mon. 



P. candidum, Link. Mycelial filaments 

 woven together, spores white. (Distinct ?) 



P. sparsum, Grev. Mycelium lax, spores 

 white. Sc. Crypt. Fl. pi. 58. fig. 2. Per- 

 haps not different from the last. 



P. fasciculatum, Sommer. Mycelium 

 scarcely developed filaments all fertile, 

 trifid at the apex, spores glaucescent. 



P. subtile, Berk. Extremely minute, my- 

 celium creeping, fertile filaments erect, sim- 

 ple or ternate : chains of spores few, spores 

 broadly elliptical. Ann. N. H. vi. pi. 14. 

 fig. 25. 



P. roseum, Link. Mycelium effused; 

 fertile filaments slightly branched, spores 

 rose-colour. 



One species (P. curtipes) has been found 

 in amber. 



BIBL. Berk. hook. Br. Flor. ii. pt. 2. 



344; Ann. N. H. i. 262, vi. 437, 2. vii. 102; 

 Greville, loc. cit. ; Fries, Syst. Myc. iii. 407 : 

 Sum. Veget. 489. See also YEAST and 

 VINEGAR-PLANT. 



PE'NIUM, Breb. A genus of Desmidi- 

 acese. 



Char. Cells single, entire, elongated, 

 straight, and slightly or not at all constrict- 

 ed in the middle. 



Sporangia round or quadrangular, smooth, 

 not spinous. 



At each end of the cells is a rounded 

 space containing moving molecules. 



Several British species (Ralfs). 



P. Brebissanii (PL 14. fig. 36). Cells 

 smooth, cylindrical, ends rounded, trans- 

 verse median band inconspicuous. Length 

 1-640 to 1-400". 



Common. Sporangium at first quadrate, 

 but finally orbicular j conjugating cells per- 

 sistent, or remaining permanently attached 

 to the sporangium. 



P. margaritaceum (PI. 14. fig. 37, empty 

 cell). Cells cylindrical or fusiform, with 

 rounded truncate ends, and covered with 

 pearly granules in longitudinal rows. Length 

 1-160". 



BIBL. Ralfs, Desmid. 148; Archer, Qu. 

 Mic. Jn. 1864, 179, 1867, 183; Hassall, 

 Alg. ; Rabenh. Alg. iii. 119. 



PENNAT'ULA, Cuv. (Sea-pen). A 

 genus of Alcyonaria (Zoophytes). 



The spicula form interesting microscopic 

 objects. 



PENTHALEUS, Koch. A genus of 

 Trombidina (Acarina). Somewhat elon- 

 gate ; anterior legs rather long and slender ; 

 femora of hind legs thickened. P.hcematopus. 

 (Koch, Uebers. ; Murray, EC. Ent. 121.) 



PENTHALO'DES, Murr., =Megamerus 

 ovalis. 



PEPLONYS'SUS, Kol. A genus of 

 Sarcoptidse (Acarina). 2 species; yellow- 

 ish-brown ; on Nycteris and Rhinopoma ; 

 Egypt. (Kolenati, Site. Ak. Wien, 1858, 

 74 ; Murray, EC. Ent. 323.) 



PEPPER. Black pepper consists of the 

 berries of Piper nigrum ; white and decor- 

 ticated pepper of the same berries with the 

 outer part of the coats removed. The cel- 

 lular tissues of the several lamellae of the 

 husk, and of the albumen or body of the 

 seed, are tolerably characteristic (PI. 2. fig. 

 12), and may be known by their appearance 

 under the microscope from the fragments of 

 linseed, mustard, &c. with which peppers 

 are sometimes adulterated. White pepper 

 is fraudulently reduced with flour, which 



