58 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Cross-Pollination and Self-Pollination. — According to Marchese 

 Burgagli,* the insect visitor chiefly efficient in the pollination of the 

 parasite Cytinus hypocystis is Bombus agrorum var. pascuorum. 



Mr. G. W. Ord f records a series of observations with regard to the 

 visits of Lepidoptera to flowers. He is of opinion that colour is a matter 

 of but little importance in the attraction of moths. On the other hand, 

 he has known insects to be attracted only by one flower which does not 

 yield nectar, viz. the elder. The stinging-nettle, although specially 

 adapted for anemophily, attracts insects of more orders than one. In 

 the ragwort and field-thistle it appears certain that the visiting insects 

 effect pollination between separate flowers of the same head. The 

 nectar-sipping habit of moths reaches its greatest development in the 

 genus Plusia. 



Ornithophilous Flowers. — E. Werth + gives an account of the 

 arrangements exhibited by flowers in Tropical Africa for pollination 

 by the agency of birds, chiefly Nectarinieas (honey-birds), the represen- 

 tatives in Africa of the American humming-birds. He classifies these 

 under 8 types, viz. : — (1) Myrtaceaa type. The attractive part of the 

 flower is usually the long white stamens (e.g. Jambosa vulgaris, Barring- 

 tonia racemosa) ; (2) Bruguiera type ; pendent, bell-shaped flowers, 

 the access to the honey between the style and the stamens (Bruguiera 

 gymnorhiza, &c.) ; (3) Ceiba type, corresponding to Delpino's Fuchsia 

 type (Ceiba pentandra); (4) Hibiscus type; tubular or bell-shaped, 

 horizontal or pendent flowers ; the organs of reproduction completely 

 enclosed or projecting (Hibiscus rosa sinensis) ; (5) Aloe type ; flowers 

 with long narrow tube, equalling in length the beak of most Kectariniere 

 (Aloe VolJcensii, &c.) ; (6) Lip-flowers ; flowers zygomorphic, lipped 

 (Kigelia eethiopica, &c.) ; (7) Erythrina type; horizontal zygomorphic 

 flowers, with strongly projecting reproductive organs (Erythrina indica, 

 &c.) ; (8) Explosive pollen tyj)e (Loranthus Dregei, &c). 



The ornithophilous sjiecies of Tropical Eastern Africa are mostly 

 characterised by conspicuous scarlet or purple flowers, or of some shade 

 of brown or orange corresponding to the colours of the plumage of the 

 male as contrasted with the female Nectarinieae. 



Schenkling-Prevot§ holds that the number of truly ornithophilous 

 flowers is much smaller than is usually stated. Among those which 

 are actually pollinated by birds he names Feijoa, Myrrhinum ; among 

 Musaceas Musa, Bavena, and Strelitzia ; Erythrina ; some Ericaceae and 

 Proteaceaa ; Loranthus Kraussianus and Dregei. Beautiful examples of 

 true ornithophily are afforded by the terrestrial bromeliuds Puya 

 chilensis and coerulea, pollinated by a starling, Curseus aterrimus. 



Cleistogamous Flowers. || — M. Leclerc du Sablon has studied the 

 cleistogamous flowers of Viola odorata. The hypodermal layer of cells 



* Bull. Soc. Bot. Hal., 1900, p. 203. 



t Trans. Nat. Hist. Soc. Glasgow, v. (1900) pp. 355-66. 



X Verhaudl. Bot. Ver. Brandenburg, xlii. (1900) pp. 222-56 (12 figs.). See Bot. 

 Centralbl., lxxxiv. (1900) p. 188. 



§ Naturw. Wochenschr., xiv. (1S99) pp. 165-8. See Bot. Centralbl., lxxxiv. 

 (1900) p. 325. 



|| Rev. Ge'n. de Bot. (Bonnier), xii. (1900) pp. 308-18 (12 figs.); Comptes- 

 Rendus, exxxi. (1900) pp. 691-2. 



