330 ON THE NATUKALs HOPES USED FOR PACKING 



new cortical rnys are projected into the four extremities of the woody 

 mass, so that the arms appear to be bifid ; these bifurcations also in tlieir 

 turn become bifid, and so the woody mass has its primary, secondary, 

 tertiary, and quaternary divisions according to its age. Further, as the 

 innermost cortical deposit — that surrounding the woody tissue — is very 

 dark, it throws into high relief the stellate outline of the woody portion. 

 I have met witli only one or two species which furnish this arrangement. 



The woody system is by no means uniform, and it requires careful 

 study before a detailed description can be given. Nearly all the 

 species, however, have numerous vessels of large diameter, so that the 

 stems are for the most part very light and porous. Such an arrange- 

 ment might have been expected in plants whose stems are only as thick 

 as a finger, and whose sap has to travel a long distance before it can 

 reach the leaves, which are for the most part met with only in the 

 uppermost portions of the stems. In most of the species this woody 

 tissue is traversed by a large number of fine medullary rays, which 

 give a beautiful figure to many of the sections. The internal arrange- 

 ment does not manifest itself in any marked way on the exterior ; 

 their form is generally cylindrical, but some of them exhibit four slight 

 projections in the form of narrow raised bantls arranged lengthwise, 

 which correspond with the outermost portions of the four cortical rays. 

 Some species have a square stem during their early growth, and even 

 the older stems do not altogether lose their four-sided character. 



MalpigldacecB. — If the Lianas which belong to the ^zyH0«/(7cg<s are re- 

 markable for the symmetry of their parts, the Lianas of this family may 

 be said to be characterized by an absence of symmetry. Li general, their 

 stems are singularly rugged in outline, a section presenting deep sinuosi- 

 ties or irregular projections, while at other times they appear to consist 

 of a number of separate branches which have become consolidated in the 

 progress of growth, so as to forma rough-looking rope of many strands. 



Jussieu gives a full account of the structure of the stem of Stigma- 

 pht/llou emarcjhiatuni (' Mcmoire,' etc., pp. 103, etc.), and Gaudiehaud 

 (' Eecherches,' etc., pi. xviii. f. 11. p. 129), figures an allied species, 

 but I have not, as yet, identified either amongst those coming with 

 cotton. I exhibit, however, a stem which appears to be the Te- 

 trapierys Guillem'miana, referred to by Jussieu, and figured by him in 

 his monograph, pi. iii. f. 5. p. 106 ; but this species does not exhibit the 

 sinuosities so characteristic of most of the Lianas of this family. 



