106 Prof. Lindley on new Orchidaceous Plants. 



This does not answer however for freshwater Algse. Some of the 

 specimens of marine Algse, mounted in Goadby's solution, such as 

 Codium tomentosum, Helminthocladia vermicularis, &c., are admi- 

 rable. 



This method of preparing Algse certainly requires some little 

 expenditure of care and patience, but it will be found so satisfac- 

 tory in its results as amply to compensate any additional pains ; 

 and when once the requisite arrangements have been made, the 

 trouble in the case of individual specimens from time to time will 

 not be found so great as might be expected. 



It may be remarked that the method is equally applicable to 

 other microscopical objects, and especially to those of vegetable 

 physiology. 



I am, my dear Sir, faithfully yours, 



M. J. Berkeley. 



XIII. — A Century of new Genera and Species of Orchidaceous 

 Plants. Characterized by Professor Lindley. 



[Continued from vol. xii. p. 398.] 



Decade 3. 



21. Pleurothallis Hartwegii ; caule medio laxe et longe vaginato, 

 folio oblongo sessili amplexicauli, spatha obtusa carinata coriacea, 

 spicis plurimis erectis rigidis secundifloris folio subsequalibus, se- 

 palis disjunctis falcatis intus pubescentibus, labello cordato ovato 

 obtuse basi auriculato (v. trilobo lobis lateralibus brevibus rotun- 

 datis) juxta sinus bilamellato. 



Popayan (Hartweg). 



Very like P. macrophylla. Stem a foot and more high. Leaf a span 

 long. Spikes eighteen to twenty. 



22. Pleurothallis Icevigata ; caule angulato medio laxe et longe 

 vaginato, folio oblongo sessili amplexicauli vernice quasi inducto, 

 spatha acuta carinata coriacea laevigata, spicis plurimis erectis ri- 

 gidis secundifloris folio brevioribus, floribus omnino P. Hartwegii 

 sed duplo majoribus. 



Popayan (Hartweg). 



Very like P. Hartwegii, but the leaves are more polished, the spikes 

 often shorter, and especially the flowers are twice as large. Perhaps 

 it is a mere variety. 



23. Stelis maxima ; folio oblongo obtuso, spica recta basi spathacea 

 triple longiore, bracteis amplexicaulibus cuspidatis internodiis 

 brevioribus, floribus ventricosis disepalis, sepalis multistriatis con- 

 cavis, 



At the foot of Mount Tunguragua, at the height of 11,000 feet 

 (Hartweg). 



