OP ARTS AND SCIENCES. 391 



ter the next year (Monog. Calic. p. 33) to Trachylia ; and this con- 

 struction is perhaps still preferable to the opinion expressed later, in 

 his Synopsis (p. 168), that the plant constitutes a genus ; the variation 

 from the type of Trachylia being only such as might be presumed pos- 

 sible within Trachylia. From T. Javanica the species above described 

 differs in its thin and powdery thallus (that of the former plant being 

 much better developed, and even approaching, at length, the thickish 

 and warted crust of T. tympanella) ; its much smaller and far less prom- 

 inent, more conspicuously white-edged apothecia ; and especially in the 

 curious differentiation of the spores, which exhibit the blunt ellipsoid 

 (or hiscoctiform) type of the genus, not merely (as in T. Javanica) ex- 

 tended to spores with three dissepiments, but also twice or even thrice 

 constricted. So strange is the effect of this latter variation, that I have 

 hesitated to describe the plant as a lichen ; but though there is no col- 

 oration of the hymenium with iodine, any more than in T. Javanica, 

 both species equally possess an evident thallus ; and their apothecia 

 and spores, as already remarked, are explicable as variations from, or 

 rather developments of, the type of Trachylia tympanella. — The genus 

 Trachylia, as here understood, (indicated by Fries in his Flora Scanica, 

 1835, and again in his Summa Veg. Scand., 1846, and taken in the 

 same sense by Torssell, a little earlier, and by the present writer in his 

 Synops. Lich. N. Eng., in 1848, as also in the various important works 

 of Dr. Nylander, q. v. in Lich. Scand. p. 44,) appears preferable to the 

 very indefinite Acolium of Fee (Ess. Crypt, p. 28, the name adopted 

 being the same as that given by Acharius to the section of his genus 

 Calicium which included C tympanellum), as it is also older than the 

 later Acolium of Massalongo, &c. And Cyphelium, Ach. in Vet. Ac. 

 Handl. 1815 (lately proposed by Th. Fries, in Gen. Heterolich. Eur. 

 p. 100, for the group represented by T. tympanella), though it included 

 Trachylia, by no means expressed it ; and is a less distinct conception. 



Cladonia Dilleniana, Floerk. : thallo squamuloso-dissecto, podetiis 

 superne infundibuliformibus prolifero-ramosis, axillis perviis sub-squa- 

 mulosis e stramineo albicantibus, fertilibus subcymosis; apotheciis fuscis. 



a. CRISPATA : straminea ; podetiis turgidis, axilHs apicibusque infun- 

 dibuliformi-dilatatis foliolis lineari-multifidis exasperatis irregulariter 

 demum proliferis. C. stenophylla, Nyl. Syn. p. 201. On rotten logs, 

 Monte Verde, Cuba, Mr. Wright. 



/3. elongata: albicans ; podetiis gracilioribus subsimpliciter repetito- 

 proliferis elongatis, axillis hiantibus foliolis multifidis cristatis. Coral- 



