CYCADOFILICALES 



27 



the species of Crossotheca are stamens of Cycadofilicales. Recently 

 Miss Benson has announced (83) the discovery of a new species of 

 Crossotheca (C. Grievii), which is described as the stamen of Heter- 

 angium Grievii. There are now recognized, therefore, nine species, 

 and all of them have the general "epaulet" character described for 

 C. Honinghausii. They differ only in such details as the form of 

 the sporangium-bearing blade (oval, cordate, or lobed), and in the 

 number and form of the sporangia. So similar are these species that 

 it seems safe to infer that they are all 

 stamens of Cycadofilicales. The foliage 

 of all of them is known, except that of 

 C. Hughesiana, and includes species 

 of Pecopteris (as P. exigua) as well as 

 of Sphenopteris (Lyginodendron). 



In 1887 KiDSTON (11) described 

 fronds of Neuropleris heterophylla 

 (Medullosa) in which both the pinnae 

 and axis end in slender, naked, dichoto- 

 mously divided branchlets, each ulti- 

 mate division terminated by a four- 

 valved body. At the time these 

 bodies were regarded simply as the 

 "fructifications" of a fern. Since the 

 seeds of this species have now been 

 discovered, it is apparent that these bodies must represent its micro- 

 sporangiate structures. "Fructifications" of this kind, terminal 

 on naked, ultimate branchlets of a more or less modified frond, 

 with valves more or less united at base, have been referred to the 

 form genus Calymmatotheca. At least some of them are sporangia 

 more or less united below and free above, and in some cases the 

 dehiscence (internal) and the spores have been found. Of course 

 such a structure is a synangium,' but its terminal relation to 

 ultimate branches of the frond is quite different from that of the 

 synangia of existing Marattiaceae. There is danger of confusing 

 these structures with the cupule-like investment of such seeds as 



Fig. 20. — Crossotheca Honing- 

 hausii: portion of frond with six 

 young stamens; X2.5. — From 

 photograph by Kidston (64). 



■ This term is used with no implication of an opinion as to the nature of 

 the structure. 



