26 Cereiis senilis^ and other Mexican Plants. 



with ivy ; the effect of which was beautiful, as the roses continued in flower 

 throughout the year. The same effect might be produced in England, by 

 having the wall flued, and protected by matting during severe weather. Where 

 the style was Gothic, the wall might be covered with a series of piers and 

 intersecting arches ; and, if the piers and imposts of the arches were covered 

 with ivy, and the rest of the wall with deciduous plants, the effect, more par- 

 ticularly in winter, would be very striking. An excellent plan for varying 

 such a wall is, to form the ground plan in a zigzag line, with piers at the 

 angles ; in which case, the length of each angle may be 10 ft., and the deviation 

 from a straight line from 2 ft. to 3 ft. In going along the walk in front of such 

 a wall, one series of angles would meet the eye; and, in returning, another 

 series. Another plan is, to have the wall straight, and a temporary or perma- 

 nent roof projecting from it. In this case, if the roof were permanent, it 

 ought to be composed of glazed sashes, which might be taken off in the sum- 

 mer season, and used for growing melons, leaving the pillars and rafters which 

 supported the sashes as fixtures ; and these might be covered with rapidly 

 growing climbing plants. Such a roof ought to extend over the walk, in order 

 that the latter may be used during rainy weather in summer ; and that, during 

 the most severe frosts in winter, it may afford a somewhat more temperate 

 place for taking exercise than in the open air. The most complete glazed ve- 

 randa of this kind would be one where the whole of the skeleton framework, 

 as well as the sashes, might be removed in summer, without leaving any marks 

 to disfigure the scene, and replaced every autumn. A temporary veranda, in 

 which the framework is to be covered with hurdles clothed with thatch, or 

 with canvass fixed to framework or oiled paper, forms a very good protection 

 for plants while in their dormant state; but requires to be removed much 

 sooner in spring when they begin to grow, than a glass roof; because, when 

 the plants begin to grow under an opaque roof, they become etiolated and 

 blanched for want of light. In general, conservative walls should be flued, in 

 order to give the gardener the power of assisting the I'ipening of the wood in 

 autumn ; and, in this case, the fireplace might be conveniently situated behind 

 the wall, as indicated in the plan, at g, where it is placed in the corner of the 

 stable buildings, A conservative wall may often form one of the sides of a 

 range of office buildings ; and this is the case with a part of the wall we are 

 now describing, which forms the side wall to the stable {t) and coach-house (Ji). 



Art. VII. Notes on Cereus senilis and some other Mexican Plants. 

 In a Letter from Mr. Tate of the Botanic Garden, Sloane Street, 

 to Mr. Beaton. Communicated by Mr. Beaton. 



I BEG to inform you that the first Cereus senilis I ever saw 

 came to this country in September, 1823, also Mammillaria 

 latispina [Echinocactus cornigera Dec.'], and several other new 

 species, which were introduced and presented to me by R. P. 

 Staples, Esq., who was appointed consul-general of Mexico, 

 after his first commercial trip there. I also purchased the same 

 species of Mr. Bullock, in the following month of the same 

 year, and it was described by Mr. Haworth in the Philosophical 

 Magazine for 1823, from the specimens brought over by Mr. 

 Bullock. I was extremely desirous that the Cereus senilis should 

 be named after Mr. Staples, but Mr. Haworth said he could 

 not consistently do so, as he believed it a true Cereus ; and as 

 Humboldt had previously described it as Cereus senilis, he 



