480 CALYX-TUBE. 



Calyx-tube. In descriptive botany it is the common 

 practice to speak of a calyx-tube, by which is meant a 

 tubular or sheathing portion at the base of the flower, 

 below the sepals or calyx-lobes, and distinct or insepa- 

 rable from the ovary. The question morphology has 

 to solve is whether this tubular structure is to be con- 

 sidered as a portion of the axis, or whether it is to be 

 regarded as composed of the confluent bases of the 

 sepals. 



Mr. Bentham, who has recently reviewed the evidence 

 as to the nature of the calyx-tube in his paper on 

 MyrtacecB^ still holds to the notion that the " calyx- 

 tube" or "hypanthium" is formed from the concretion 

 of the basal portions of the sepals. He founds his con- 

 clusions upon such facts as the following : the circum- 

 stance that the point of origin of the leaf is not always 

 the same as the point of disarticulation or separation 

 from the axis, inasmuch as the basal portion of the 

 leaf is often adherent to the stem for some distance, 

 though still recognisable as foliar not axial in its nature. 

 In the same manner, the corolla and androecium may 

 be concrete at the base, so that the stamens are for 

 convenience' sake described as inserted into the tube of 

 the corolla, though it is generally admitted that both 

 stamens and petals are really hypogynous, and it is 

 not usual to consider the corolla-tube up to the diver- 

 gence of the stamens as part of the receptacle. A 

 similar remark applies to the carpels and pla- 

 centas. Mr. Bentham further considers that the 

 gradual disconnection of the various whorls, that may 

 be traced in many plants, is a further proof of concre- 

 tion, rather than of expansion of the axis, but this 

 argument may fairly be met by the consideration that 

 the several whorls emerge at different heights.^ 



Organs originally free and distinct become ultimately 

 combined at the base by the gradual protrusion from 



' ' Joum. Linn. Soc.,' vol. x, p. 103 et eeq. 



' See also the receptacular tube (ovary ?) of Baeckea l!)eai*ing stamens, 

 see p. 183. It would be natuml to see stamens springing from the recep- 

 tacle but not from the ovary. 



