The Morphology of Ruppia Maritima. 101 



5. The floral scale leaf fsi), adherent to the base of the peduncle 

 in a position corresponding to that of the vegetative scale leaf ; 



6. The branch {axbr), arising in the axil of the upper subfloral 

 leaf; 



7. The upper subfloral leaf {up. sfl)} 



4. Summary of Distinguishing Characters. 



Irmisch (1851) has described the inflorescence in Ruppia rostel- 

 lata. His account is in part as follows: "Die folia floralia bilden 

 nun zwei Achseln, aus denen Zweige hervorbrechen, welche sich 

 folgendermassen verhalten. Das erste tief an der Basis der Zweige 

 stehende Blattgebilde ist eine diinnhautige abgestutzte lanzettliche 

 Schuppe, die sich um den Grund des Zweiges herumlegt. Ich will 

 sie Vorblatt nennen. Es steht dasselbe, wie das auch sonst regel- 

 massig der Fall ist, mit seiner Rtickseite wegwarts vom Mutterblatte 

 des Zweiges und dam Bliitenstande A zugewendet"; — and further, 

 " Der Zweig in der Achsel des obern fol. flor. ist dem des untern 

 in der aussern Bildung gleich." 



In this and his description following, it is clearly evident that 

 Irmisch considered the floral scale leaf and the vegetative scale 

 leaf in an inflorescence to be identical, for he alludes to nothing but 

 a vegetative scale leaf (Vorblatt) at the base of each branch. Of 

 course it is possible that no floral scale leaf, as such, occurs in 

 Ruppia rostellata, yet the two species are evidently quite similar. 

 For example, Sauvageau (1891. II) finds no differences in the struc- 

 ture of their foliage leaves. 



To sum up the differences between floral and vegetative scale 

 leaves, they are in brief as follows. 



1. Shape. The floral scale leaf differs markedly in shape from 

 the vegetative scale leaf. A large number of specimens was examined 

 and this difl^erence was constant. 



2. Position. As shown in Text-fig. 20, but more clearly were the 

 section cut at a lower plane, the floral scale leaf does not envelop 

 the axillary shoot as does the vegetative, but is turned toward and 

 partially surrounds the young flower or the peduncle, according to 

 the stage of floral development. 



3. Development. The growth of the floral scale leaf is always 

 correlated with the growth of the peduncle and flower — even when 

 the axillary structure adjacent is as yet rudimentary. In case the 



' The axillary scales have been purposely omitted. The cross section 

 represented in Text-iig. 20 was cut above them. 



