PTERYGIUM. 



[ 645 ] 



PUCCINIA. 



upon bats. Several species have been de- 

 scribed. 



BIBL. Gervais, Walckenaer's Apteres, iii. 

 227 ; Duf our, Ann. Sc. N. xvi. 98, xxv. 9 ; 

 Koch, Deutschl. Crustac.; Murray, EC. Ent. 

 175. 



PTERYGIUM, Nyl. A genus of Colle- 

 maceous Lichens. 2 species, on calcareous 

 rocks. (Leighton, Lichen Fl. 12.) 



PTERYGO'NIUM, Sw. A genus of 

 Mosses. See NECKEBA. 



PTILID'IUM, Nees. A genus of Jun- 

 germanniese (Hepaticse), containing one ele- 

 gant British species, P. ciliare, frequent on 

 heaths and rocks in subalpine districts, but 

 rarely found in fruit. 



BIBL. Hooker, Br. Fl ii. 126; Br. Jung. 

 pi. 65 ; Ekart, Jung. pi. 5. fig. 36. 



PTILO'TA, Ag. A genus of Ceramiacese 

 (Florideous Algae), with flat feathery fronds 

 a few inches high; of a deep red colour, 

 growing on Laminariae or Fuci, or on rocks 

 between tide-marks. The fructification 

 consists of: 1. clustered roundish favellce 

 containing spores, terminating the ultimate 

 pinnules, and surrounded by an involucre 

 of subulate ramuli, or naked ; 2. tetrahedral 

 tetraspores on short pedicels fringing the 

 pinnules. Antheridia have not been ob- 

 served. P. plumosa (PI. 4. fig. 16). 



BIBL. Harvey, Mar. Alg. 159, pi. 22 A ; 

 Phyc. Br. pi. 70 ; Greville, Alg. Br. pi. 16 ; 

 Nageli, Algensystem, pi. 6. figs. 38-42. 



PTYCHOG'RAPHA, Nyl. A genus of 

 Graphidei (Lichenaceous Lichens). 1 sp., 

 on decorticated mountain-ash. (Leighton, 

 Lich. Fl. 392.) 



PTYCHOS'TOMUM, St. A genus of 

 Holotrichous Infusoria. Free, ovate, un- 

 symmetrical, mouth ventral. 2 species, in 

 the intestines of Annulata (Tubifex}, and 

 Mollusca (Paludina). (Kent, Inf. 541.) 



PTYGU'RA, Ehr. A genus of Rotatoria, 

 of the family Ichthydina. 



Char, Eyes none; no hairs upon the 

 body ; tail-like foot cylindrical, simply trun- 

 cate. 



Teeth three in each jaw ; anus situated 

 at the end of the tail-like foot. 



P. melicerta (PL 44. fig. 2 L). Body terete- 

 clavate, turgid in front, hyaline; mouth 

 with two little hook- like horns ; cervical 

 process single and smooth. Freshwater ; 

 length 1-144". Ehrenberg questions whe- 

 ther this is not a young form of another 

 genus. 



BIBL. Ehrenberg, Inf. 387 ; Hudson, 

 Mn. M. Jn. xiv. 165. 



PTYXID'IUM, Perty. A genus of Eu- 

 chelia. It should probably be included in 

 LEUCOPHBYS. 



BIBL. Pritchard, Infusoria, p. 615. 



PUCCIN'IA, Persobn. A'genus of Ure- 

 dinei (Hypodermous Fungi), containing 

 numerous parasitical species, growing upon 

 the leaves and other herbaceous parts of the 

 higher plants, forming "mildews," and with 

 their Uredinous forms, "rusts" &c. These 

 Fungi have received considerable attention 

 lately from Tulasne, De Bary, and others ; 

 and it appears that the genera Uredo and 

 others have no distinct existence, but are 

 preparatory forms of Puccinia and other 

 genera noticed under UBEDINEI. In the 

 article ^EciDiuM we have described the 

 twofold reproductive structures, namely the 

 spermogoma and the perithecia (figs. 6 & 6 a, 

 p. 19 ; PI. 26. figs. 1-4), producing respect- 

 ively the spermatia (supposed to have the 

 office of spermatozoids) and the spores. In 

 Puccinia three forms of reproductive organs 

 occur : first, spermogonia analogous to those 

 of ALcidium ; then the forms called Uredines 

 (chiefly of the supposed genus TricJiobasis), 

 producing globular unilocular bodies, shortly 

 stalked, and with transparent walls, but 

 with yellow or orange-coloured contents; 

 and lastly the true Puccinics, containing 

 bilocular spores borne on short stalks, and 

 having a dark-brown integument. The 

 latter present remarkable phenomena in 

 germination, which may be best observed 

 in those which sprout without becoming 

 detached from the matrix, such as P. gra- 

 minis, which however remain quiescent 

 until the spring folio wing their development, 

 while P. Glechom&jBuxi, Dianthi, and others 

 germinate in the same summer. The bilo- 

 cular spores have each one pore (analogous 

 to the pores of PoLLEN-grains), from which 

 extends a filamentous process, ultimately 

 giving rise to four short processes, each 

 terminating in a pointed process bearing a 

 sporidium, of more or less curved elliptical 

 form. About the time when these fall off, 

 the filament bearing the four processes be- 

 comes divided by septa into four chambers, 

 but then appears to die. The sporidia ger- 

 minate and produce a filament, which, in- 

 stead of becoming the basis of a mycelium, 

 reproduces a sporidium smaller than the first. 

 More is said respecting these remarkable 

 organisms under the head of UBEDINEI. 



The PucdnicB present the following ge- 

 neral characters: The spermogonia rare, 

 scattered on either face of the infested leaf. 



