PRIMULACEAE 



75 



1829. P. saccharata Mill. 



Visitors. Loew observed the bee Anthophora pilipes F. $, skg., in the Berlin 

 Botanic Garden. 



1830. P. sinensis Sabine. (Ljungstrom, Bot. Not., Lund, 1884, pp. 171-4.) 

 Ljungstrom observed cleistogamous flowers on plants of this species cultivated under 

 glass. These possessed a bell-shaped calyx, and a short closed tubular corolla, with 

 faint indications of lobes, and of a pale yellowish green colour. The anthers were 

 very small, and also the pollen-grains, these being only 14 /a long, while those of the 

 long- and short-styled chasmogamous flowers were respectively 32 /x and 24 /x in 

 length. One plant was long-styled, with the style bent in the middle and enclosed 

 in the corolla. In short-styled flowers the style was straight. Fruits and seeds were 

 not observed. 



544. Hottonia Boerh. 



Flowers heterostylous dimorphous, with concealed nectar, secreted at the base of 

 the ovary and stored up in the corolla-tube. Sometimes cleistogamy. 



1831. H. palustris L. (Darwin, ' Forms of Flowers,' pp. 50, 52, 252, 254 ; 

 Sprengel, ' Entd. Geh.,' p. 103; John Scott, J. Linn. Soc, Bot., London, viii, 1865; 

 Herm. Muller, ' Fertilisation,' pp. 386-9, ' Weit. Beob.,' Ill, p. 65 ; Knuth, ' Bloe- 



FiG. 246. Hottonia palustris, L. (after Herm. Muller). (i) Long-styled flower. (2) Stigmatic 

 papillae of do. (3) Short-styled flower. (4) Stigmatic papillae of do., enlarged to same scale as (2). 



menbiol. Bijdragen ' ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 446-7.) 

 Sprengel discovered heterostyly in this species, about which he makes the following 

 remarks (loc. cit.) : 



' Some plants only bear flowers with stamens inside the corolla-tube but the 

 style projecting from it, and others only flowers with the style shorter and the stamens 

 longer than the tube. I do not believe that this is accidental, but an arrangement of 

 Nature, though I am unable to explain its meaning.' 



The corolla-tube of the white or reddish flowers is 4-5 mm. long, and the 

 shorter reproductive organs are placed in its opening, while the longer ones project 

 3-4 mm. from it. Insect visitors when probing for nectar touch the two kinds of 

 organ with different parts of their bodies, and thus regularly eff"ect legitimate crossing. 



