PTEROPTUS. 



[ 542 ] 



PUCCINIA. 



P. patina (PI. 35. fig. 20). Testula mem- 

 branous, orbicular, crystalline, roughish 

 near the broad margin ; a depression present 

 between the rotatory lobes. Aquatic ; length 

 1-120". 



BIBL. Ehrenberg, In/us, p. 516. 



PTEROPTUS, Dufour. A genus of 

 Arachnida, of the order Acarina, and family 

 Gamasea. 



Char. Body depressed; last joint of palpi 

 longest; legs stout, with short joints. 



P. vespertilionis (PI. 2. fig. 39). Found 

 upon bats. Several species have been de- 

 scribed, but the subject requires revision. 



BIBL. Gervais, JValckenaer's Apteres, iii. 

 227 ; Dufour, Ann. d. Sc. nat. xvi. 98 ; xxv. 

 9 ; Koch, Deutschlands Crustac. 



PTERYGONIUM, Sw. A genus of 

 Mosses. See NECKERA. 



PTILIDIUM, Nees. A genus of Junger- 

 mannieae (Hepaticaceae), containing one ele- 

 gant British species, P. ciliaris, frequent on 

 heaths and rocks in subalpine districts, but 

 rarely found in fruit. 



BIBL. Hooker, Brit. Flor. ii. p. 126, Brit. 

 Jung. pi. 65 ; Ekart, Synops. Jung. pi. 5. 

 fig. 36. 



PTILOTA, Ag. A genus of Ceramiaceaj 

 (Florideous Algae), with flat feathery fronds 

 a few inches high; of a deep red colour, 

 growing on Laminarice or Fuci, or on rocks 

 between tide-marks. The fructification con- 

 sists of 1. clustered roundish favellce con- 

 taining 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. 



BTBL. Harvey, Brit. Mar. Alg. p. 159. 

 pi. 22 A, Phyc. Brit. pi. 70 ; Greville, Alg. 

 Brit. pi. 16 ; Nageli, Neuer Algensysteme, 

 pi. 6. fig. 38-42. 



PTYGURA, Ehr.A genus of Rotatoria, 

 of the family Ichthydina. 



Char. Eyes none; no hairs upon the 

 body ; tail-like foot cylindrical, and simply 

 truncate. 



Teeth three in each jaw; anus situated 

 at the end of the tail-like foot. 



P. melicerta (PL 35. fig. 21). Body terete- 

 clavate, turgid in front, hyaline ; mouth with 

 two little hook-like horns ; cervical process 

 single and smooth. Aquatic; length 1-144". 



Ehrenberg questions whether this is not 

 a young form of another genus. 



BIBL. Ehrenberg, In/us, p. 387- 



PUCCINIA, Persoon. A genus of Caeo- 



macei (Coniomycetous Fungi) (see also 

 UREDINES), containing numerous para- 

 sitical 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 prepara- 

 tory forms of Puccinia and other genera 

 noticed under UREDINES. In the article 

 ^EciDiUM we have described the twofold 

 reproductive structures, namely the sperma- 

 gonia and the perithecia (figs. 5 & 6, p. 15; 

 PL 20. figs. 1-4), producing respectively the 

 spermatia (supposed to have the office of 

 spermatozoids) and the spores. In Puccinia 

 three forms of reproductive organs occur : 

 first, spermagonia, analogous to those of 

 ^Ecidium ; then the forms called Uredines 

 (chiefly of the supposed genus Trichobasis), 

 producing globular unilocular bodies, shortly 

 stalked, and with transparent walls, but with 

 yellow or orange-coloured contents; and 

 lastly, the true Puccinice, containing bilocu- 

 lar spores borne on short stalks, and having 

 a dark brown integument. The latter pre- 

 sent remarkable phosnomena in germination, 

 which may be best observed in those which 

 sprout without becoming detached from the 

 matrix, such as P. graminis, which however 

 remain quiescent until the spring following 

 its development, while P. Glechomce, Bund, 

 Dianthi, and others, germinate in the same 

 summer. The bilocular 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 pro- 

 cess bearing a sporidium, of more or less 

 curved elliptical form. About the time when 

 these fall off, the filament bearing the four 

 processes becomes divided by septa into four 

 chambers, but then appears to die. The 

 sporidia germinate and produce a filament, 

 which, instead 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 

 UREDINES. 



The PuccinicB present the following gene- 

 ral characters : The spermagonia rare, scat- 

 tered on either face of the infested leaf, with 

 an immersed, ostiolate peridiole, bearing 

 long cilia at the mouth, pale, orange or 

 blackish in colour. The Uredinous fruits 

 are scattered or grouped in circles, devoid of 



