CHAP. II. DISK. 161 



they are called sterile stamens, and are frequently only to be 

 recognised by the position they bear with respect to the other 

 parts of the flower. Botanists consider every appendage, or 

 process, or organ, that forms part of the same series of organs 

 as the true stamens, or that originates between them and the 

 pistil, as stamens, or as belonging to what Roper calls the 

 androeceum, namely, to the male system ; and every thintr on 

 the outside of the fertile stamens is in like manner usually 

 referred to modifications of petals, a remarkable instance of 

 which is exhibited by Passiflora. The appearances assumed 

 by these sterile stamens are often exceedingly curious, and 

 generally extremely unlike those of the fertile stamens; thus 

 in Canna they are exactly like the petals ; in Hamamelis they 

 are oblong fleshy bodies, alternating with the fertile stamens ; 

 in Pentapetes they are filiform, and placed between every 

 three fertile ones ; in Scitaminea^ they are minute gland-like 

 corpuscles, a very common form (Plate IV. fig. 10. c) ; in 

 Brodiaja they are bifid petaioid scales ; and in Asclepiadeffi 

 they undergo yet more remarkable transformations. Dunal 

 calls these sterile stamens lepals {lepala) ; a term which has not 

 yet been adopted. 



9. Of the Disk. 



By this term are meant certain bodies or projections, situ- 

 ated between the base of the stamens and the base of the 

 ovary, but forming part with neither ; they are referred by 

 the school of Linnaeus, along with other things, to nectarium : 

 Link calls them sarcoma and perigynium ; and Turpin, phy- 

 costemones. The most common form is that of a fleshy ring, 

 either entire or variously lobed, surrounding the base of the 

 ovary (Plate V. fig. 4. e, 8. d), as in Lamium, Cobtea, Gra- 

 tiola, Orobanche, &c. ; in Gesnerieae and Proteaceje the disk 

 consists of fleshy bodies of a conical figure, which are 

 usually called glanduU hypogijnce. It occasionally assumes 

 the appearance of a cup, named by De Candolle in Pseonias 

 and Aconites lepisma, a bad term, for which it is better to say 

 discus cyathiformis. In flowers with an inferior ovary (Plate 5. 

 fig. 9. c, 7. c) the disk necessarily ceases to be hj-pogynous, and 

 generally also to appear in the form of scales. * In^Composit* 



M 



