RUBIACEAE 541 



species the corolla-tube is scarcely 2 mm. long : the anthers occupy its throat, and 

 the two capitate stigmas are situated a little below the middle of it. Nectar-sucking 

 insects touch the stigmas and anthers with opposite sides of their proboscis, and 

 therefore usually effect geitonogamy or xenogamy. The stamens converge towards 

 the end of anthesis, so that pollen can fall upon the stigmas, and effect automatic 

 self-pollination as a last resort if insect-visits have failed. Schulz also observed 

 protandry. 



Visitors. Herm. Muller (Thuringia) saw a Muscid (Ulidia erythrophthalma 

 Mg., skg.), several small ichneumon flies, and a small Gelechid moth, skg. Rossler 

 records the Pyralid Orobena limbata Z., for Wiesbaden. 



1239. A. stylosa Boiss. 



Visitors. Loew saw Apis, skg., in the Berlin Botanic Garden. 



1240. A. scoparia Hook, f., and 1241. A. pusilla Hook. f. (=A. Gunnii 

 Hook./.). These two Tasmanian species are described by Treviranus as dimorphous 

 (Bot. Ztg., Leipzig, xxi, 1863, p. 6). 



395. Rubia L. 



Flowers small, greenish ; homogamous, with exposed nectar. 



1242. R. tinctorum L. (Kirchner, ' Beitrage,' p. 69.) Although the flowers 

 of this species are united into cymose inflorescences, they are not at all conspicuous, 

 owing to their small size and green colour. Kirchner gives the diameter of the flat 

 corolla as 5 mm. When the flowers open, the almost sessile anthers have already 

 dehisced. The two rounded stigmas are borne on such short styles that they are 

 situated about the level of the lower part of the anthers. They remain in this 

 position for some time after the anthers shrivel up, and continue to be receptive. 

 Automatic self-pollination is easily effected, and regularly takes place. Kirchner, 

 however, observed insect visitors (small sucking Hymenoptera and flies), by which 

 crossing may be brought about. Nectar is secreted in the base of the saucer-shaped 

 corolla-tube (only half a mm. deep), and is accessible to all comers. 



396. Galium L. 



Herm. Muller, ' Fertilization,' pp. 300-2. 



Flowers white or yellow in colour ; arranged in cymose inflorescences : with 

 exposed nectar. Hermann Miiller says that the transfer of pollen to the stigmas 

 is chiefly effected by the feet and only to a lesser extent by the proboscis of insect 

 visitors that creep about the inflorescences. Probably automatic geitonogamy of the 

 small crowded flowers is possible in all species by the fall of pollen upon the stigmas 

 of flowers at a lower level. 



1243. G. cruciata Scop. (Darwin, 'Different Forms of Fls.,' p. 286; Kirch- 

 ner, Flora v. Stuttgart/ p. 666, * Neue Beob.,' p. 65.) The inconspicuous greenish- 

 yellow flowers of this species smell like honey, and are arranged in scanty 

 inflorescences (helicoid cymes). Darwin and Kirchner describe them as andro- 

 monoeciously distributed, the lower ones being male, and the upper ones hermaphro- 

 dite. Schulz (' Beitrage,' I, p. 66) investigated very numerous plants from different 



