142 ANGIOSPERMAE—DICOTYLEDONES 



are larger and possess a corolla-tube 5 mm. long. Kerner states that in the 

 higher mountain stations they are of a deeper blue colour than in the plains. 

 MacLeod observed gynodioecism at Ghent. ' 



Visitors. — The following were recorded by the observers, and for the localities 

 stated. — 



Knuth, the hover-fly Syrphus ribesii Z., freq., skg. Herm. Muller, an Empid 

 (Empis opaca F., very freq., skg.) and a butterfly (Lycaena icarus Rott., skg.). 

 Sickmann (Osnabriick), the Sapygid Sapyga quinquepunctata F. MacLeod (Flanders), 

 the honey-bee, a short-tongued bee, 5 hover-flies, 6 Muscids, a butterfly, and a beetle 

 (Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 335-7). Scott-Elliot (Dumfriesshire), 

 3 hover-flies and 2 Muscids ('Flora of Damfriesshire,' p. 121). 



2008. M. cespitosa Schultz. (MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, 

 p. 337.) — The mechanism of this species is similar to that of M. palustris, though the 

 flowers are smaller. Automatic self-pollination is possible. 



20og. M. parsiflora Mikan. (Schulz, ' Beitrage, II, p. n 5.) — The homo- 

 gamous flowers of this species are bright-blue, rarely white in colour, and arranged 

 in scanty cymes. The style projects as far as the middle of the anthers, so that 

 automatic self-pollination is inevitable. Cross-pollination by means of insects is 

 possible. 



Visitors. — Schulz observed 2 flies, including Rhingia rostrata L. 



2010. M. pyrenaica Pourr. (=:M. sylvatica Hoffm., according to the Index 

 Kewensis!). — 



Visitors. — MacLeod (Pyrenees) observed 2 bees, 5 Lepidoptera, a Bombyliid, 

 2 Syrphids, and 7 Muscids (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, pp. 311-12). 



617. Cordia L. 



Darwin (' Different Forms of Flowers,' p. 117) describes dimorphism, but the 

 differences between the stamens, pistils, and pollen-grains of the two forms are very 

 small. 



LXXif. ORDER CONVOLVULACEAE JUSS. 



Literature. — A. Peter, ' Convolvulaceae,' in Engler and PrantI, 'D. nat. 

 Pflanzenfam.,' IV, 3 a, p. 9. 



Flowers usually brightly coloured, and adapted to the visits of insects of the 

 most various kind. In many cases they remain open only for a day or a few 

 hours, then closing permanently. The edge of the withering corolla curls inwards 

 and helps the corol'a-tube to protect the ovary. Many exotic species possess extra- 

 floral nectaries which keep insects unsuited for the transfer of pollen away from 

 the flowers (e. g. species of Ipomoea, Pharbitis, Calonyction, and Quamoclit). 



618. Convolvulus L. 



Horaogamous, more rarely protandrous or protogynous flowers with concealed 

 nectar ; or homogamous Lepidopterid flowers. Nectar secreted by the base of the 

 ovary. Occasional gynodioecism. On account of the narrow tubular nectar- 



