1692 



A TEXTBOOK OF THEORETICAL BOTANY 



The flowers are mostly pink or yellowish-green in colour and are 

 usually associated together in pendulous racemes. The nectar may be free 

 or concealed and is secreted by an epigynous disc. In R. alpimim the nectar 

 is secreted in a shallow depression of the receptacle and is accessible to very 

 short-tongued insects. In R. nibriim the depression is much deeper and 

 only the bottom is covered by nectar. It is pollinated by bees. In R. 

 iiva-crispa the flowers, unlike those of R. riibnun, are somewhat narrow and 



A B C 



Fig. 1553. — Ribes uva-nispa. Successive stages of anthesis, showing at B the secondary 

 exsertion of the stigmas and at C the infolding of the calyx at the close of anthesis. 

 (After Knuth.) 



the opening is protected by stifi" hairs which project from the edges of the 

 receptacle and the style. Such flowers can be pollinated by bees but not by 

 flies. In R. nigrum the bells are deeper, being almost spherical and pendu- 

 lous, and are better adapted for bee pollination than R. riihrum. In R. 

 sanguineiim the flowers are tubular and erect in position. Long-tongued 

 bees can reach the nectar, but in R. aureum the tubes are considerably 

 longer, i.e., 11 mm. as against 5 mm., and consequently the nectar can only 

 be reached by lepidopterous insects. 



Turning finally to the last sub-family, we have the single genus Bauera, 

 with three species in eastern Australia and Tasmania. B. rubioides is the 

 state flower of New South Wales. 



As has already been pointed out, Hutchinson and others elevate several 

 of these sub-families to the rank of families. The group however is probably 

 united and we have preferred to keep them together. 



PARIETALES 



The Parietales are Archichlamydeae in which the flowers are actino- 

 morphic or zygomorphic and generally monoecious with a separate penta- 

 merous calyx and corolla. There may be five stamens or a multiple of that 

 number. The ovary consists of three united carpels and may be superior 



