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VEGETATIVE FEATURES. 



THE FOLIAGE OF CYCADEOIDEA INGENS (TYPE). 

 The type trunk of C. ingens is of large columnar to barrel-shaped form, some- 

 what flattened, as are most Black Hills and other cycadeoidean trunks. It is a 

 magnificent flower and leaf bearing specimen, complete less the roots, and has a 

 height of 85 cm., with a girth of 170 cm. and a weight of 304 kilograms. (See 

 plates i-iii.) The leaf-base ends or "scars" are unusually large, being 3.5 to 

 5 cm. wide and 2 to 3.5 cm. high, with the lateral angles drawn out to sharp points 



by the incurving sides. In life, bisporangiate 

 strobili were embedded between the leaf bases at 

 various points, and a number of basal portions 

 of such are readily to be noted; but only one 

 such strobilus was preserved entire. This, as 

 stated, was removed for study and described in 

 1899. Its position near the summit of the 

 trunk is shown in plate I. All the portion of 

 the summit above this flower bud may be con- 

 sidered the true crown of the trunk, the surface 

 being rounded rather than conical, and of ellip- 

 tical outline with a long diameter of 25 cm. 

 and a short diameter of about 20 cm. This 

 crown is made up of a dense mass of ramentum, 

 in which are embedded, just above the flower 

 and older leaf bases, various half-grown and 

 partially emergent fronds, and still nearer the 

 summit a number of young fronds as yet en- 

 tirely immersed in ramentum. Of the latter, 

 five have been found in the portions of the sum- 

 mit removed, three being shown in thin trans- 

 verse section on plate xix, photographs 1 to 3. 

 Of the half-grown fronds one was secured with 

 its lower pinnules not yet emergent, as in the 

 transverse section shown on plate xxxi, photo- 

 graph 6. It is thus seen that a completely pre- 

 served and nearly mature bisporangiate strobilus 

 was present among the full-grown leaf bases 

 near the summit of the trunk, and that a con- 

 siderable number of such strobili, some of 

 which had possibly matured, were seated on 

 the lateral trunk surface, though for the greater 

 part broken away ; while above the uppermost strobilus or flower are partially 

 emergent fronds, and still more nearly apical than these a number of very young 

 fronds, with their pinnules quite well developed, but with their rachides as yet 

 short and of only sufficient length to bear the closely ranked pinnules. The full 

 number of these smaller fronds has not been determined, but at least half a dozen 

 are present. Plainly, after having formed its blossoms this cycad was again actively 



Fig. 46. — Prefoliation and frond emergence of 

 existing cycads. Type I . 



Dion edule. Summit of trunk with mature 

 fronds cut away so as to show five emergent 

 young fronds (a). Transverse section of 

 same (b). The rachis and pinnules of the 

 erectly prefoliate fronds undergo simultaneous 

 elongation and growth. Both figures are 

 natural size. 



