74 STAMENS. 



of the calyx. It was on this circumstance that Linnaeus founded 

 his test for the distinction of calyx and corolla. If the stamens 

 were opposite the segments of the floral envelope, he called it a 

 calyx ; if alternate, it was to be called a corolla. When but 

 one row of each is developed, this is no doubt an undeviating 

 criterion ; but it may happen, supposing the real corolla to be 

 present, that the whorl of stamens next above it is suppressed 

 and the second whorl only developed. In such cases, the 

 stamens would necessarily be opposite the segment; but by 

 the replication of Linnaeus' criterion, the inner envelope would 

 be a calyx and the outer the corolla, as in the whole order of 

 Primulacece, m which the regular calyx is present. This ar- 

 rangement may easily be accounted for upon the above suppo- 

 sition ; and it receives confirmation from the fact, that some 

 plants having twice as many stamens as petals, and having the 

 appearance of being in a single row, yet half of them are alter- 

 nately longer than the other half. This occurs in the Oxalis, 

 giving probability to the supposition that the five short stamens 

 of the Oxalis were prevented from being developed as perfectly 

 as the other five ; and had they been entirely prevented, we should 

 thus have had an arrangement similar to the Lysimachia with 

 the opposite stamens. 



The number of stamens is generally the same as the petals or 

 lobes of the corolla, or a multiple of the number. 



119* Whatever may be the apparent origin of the stamen, 

 its real origin is always the same, that is, between the base of 



Fig. 119. Fig. 120. 



Fig. 121. 



Stamen perigynous. Stamen epigynoos. Stamen hypogynous. 



the petals and that of the ovarium. Their apparent origin 

 varies remarkably, sometimes appearing to rise from the ca- 

 lyx (Fig. 119), when they are said to be perigynous ; at other 

 times they rise from the pistil itself (Fig. 120), and are said to 



How in the order Primulaceae ? How accounted for? What is usually 

 the number of stamens? — 119. What is always the origin of stamens? 

 When perigynous ? 



