006 MR. W. C. WILLIAMSON ON THE HISTORY OF ZAMIA GIGAS. 



they differ from Dion edule, and approach Encephalartos Coffer, to the leaflets of which 

 ktter species, as well as to those of Encephalartos Icmuginostts, those of Zamia Gigas bear 

 a close resemblance. Both Miquel and Brongniart have pointed out that the fronds 

 • vhibit a much closer affinity with the African and East-Indian forms than with the 

 true Zamia of the American continent. The fronds vary in size, but have often attained 

 a length of 3 feet. 



The Peduncle. — Several examples have occurred of a stem or axis covered with lar^e 

 acuminate scales arranged in ascending spiral lines. One of these, in the Scarborough 

 Museum, first satisfied me that they were the squamous peduncles which had supported 

 the singular organisms already referred to, and which I believe to be the organs of fruc- 

 tification. Each peduncle appears to have been from 6 inches to a foot, or even more, 

 in height, sometimes simple, at others branched. 



a 



A bifurcated specimen, belonging to Mr. Ripley, is about 2 inches in diameter. After 

 ascending vertically for 7 inches, it dichotomizes, each branch being between 4 and 5 

 i nches i n length , and about 1| inch in diameter immediately above the divergence, but 

 expanding to about 3 inches at its upper extremity. The scales with which it is covered 



ire arranged in a spiral manner, a distribution still better shown in some other frag- 

 ments which I have seen. Each scale is about 3 inches long, and marked with numerous 

 linear stria?. It is very much dilated at its base, where it clasps the stem, but contracts 

 towards its obtusely acuminate apex. Its upper portion exhibits a slight tendency to 

 the development of a dorsal ridge or keel, but which bears no resemblance to a true 

 midrib. At the extremity of the branch, the spiral arrangement of the scales is less 



>bvious, giving place apparently to a more circular one at the place where the terminal 

 organism has been attached. In this specimen many of the scales have disappeared, 

 owing partly to then- accidental fracture, leaving little more than the mass of carbona- 

 ceous matter found by their compressed bases ; but at the apex, especiallv of one of 

 the branches and at the point of divergence, they are more perfect. 



Organ* of Fructification. -The portions of Zamia Gigas which, next to the fronds, 

 are most frequently met with are the organisms already referred to, consisting ordinarily 



M one or more circles of long lanceolate incurved scales, which, when complete, enclose 

 ana are surmounted by other appendages. In the examples commonly seen, there is 

 nothing preserved but the whorl of scales, as in Plate LIL figs. 6 & 7 Kg. 6 is the 



ZZ 1? ™ ^ m ? ° Wn Cabinet ; the lanceo1 ^ ^ales spring from a central 



d 



li 



m outwards and upwards, then curving inwards at their upper half. I would 



L ' ''" f ,° f th ° ^ ni the ^lucrum, regarding the scales as bracts. The 



.at here are frequently two or more overlapping layers of scales. This 



Inch the base of 



^.ecmen ls valuable because it is the only one I hav 



^^^t:^ 1 mg the sma11 size of the ™*y «* of a- p— ** This 



hi„,„l Z 1 1 1 P "" aS re P reSented - %*• 5 & 7, where. owin 2 to their extreme 



Part, the bases of the scales have bee 



d ?•«!<"»<". „,,," I to,,, on the contra^ 



broken off. 



margi 

 sessile 



f the le ;l f, und that , . } . UitU >' ™ at abou t two-thirds of the nervures disappear at the upper 



• 9 their hranehmg, the leaf eontains fully one-third more nervures than start from the 



