PORTULACEAE 201 



XVI. ORDER PORTULACEAE JUSS. 

 140. Portulaca Toum. 



Small, yellow, homogamous flowers, not infrequently cleistogamous or pseudo- 

 cleistogamous. 



498. P. oleracea L. (Kirchner, ' Flora v. Stuttgart,' p. 254 ; Kerner, ' Nat. Hist. 

 PI.' Eng. Ed. 1,11; Battandier, Justs bot. Jahresber., Leipzig, xi (1883), 1885, p. 472 ; 

 Halstead, op. cit., xvi (r888), 1890, p. 562.)— Kerner says that the golden-yellow 

 flowers are devoid of honey and odour, and only open for about five hours on 

 sunny mornings. Between the bases of the stamens and petals there is a fleshy 

 ridge beset with glassy papillae. These do not secrete, but, according to Kerner, 

 insects readily feed upon them. Stamens and stigmas mature simultaneously. 

 Kirchner states that the latter lie between the anthers in such a way that automatic 

 self-pollination is inevitable. Crossing, however, would appear to take place 

 occasionally, for flies and ants have been seen as visitors. According to Kerner, 

 automatic self-pollination only occurs when the flower closes, and also in the pseudo- 

 cleistogamous flowers that remain shut during bad weather. Halstead describes 

 the stamens as sensitive, and Hansgirg states that ihey curve in the direction of 

 the stimulus. Cleistogamous flowers have been observed by Battandier. 



499. P. grandiflora Lindl. — De Bonis says that this species produces 

 cleistogamous flowers. 



141. Montia Mich. 

 Small white flowers, often pseudocleistogamous. 



500. M. minor C. C. Gmel. (Axell, ' Om Anordning. for Fanerog.Vaxt. Befrukt.,' 

 p. 13; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 391.) — Axell describes the open 

 flowers as homogamous. Both he and Kerner state that numerous flowers are 

 pseudo-cleistogamous during bad weather, remaining closed and fertilizing themselves. 



Visitors. — In Dumfriesshire, 2 Muscidae haye been observed (Scott-Elliot, 

 'Flora of Dumfriesshire,' p. 31). 



501. M. rivularis C. C. Gmel. — According to Vanhoff'en this species flowers 

 and fruits regularly in Greenland (see Abromeit, 'Bot. Ergeb. v. Drygalski's Gron- 

 landsexped.,' pp. 22-3). 



142. Claytonia Gronov. 



502. C. alsinoides Sims. — The flowers of this species in the Cambridge 

 Botanic Garden are protandrous, according to Willis (J. Linn. Soc. Bot., London, 

 XXX, 1895). They secrete nectar at the bases of the filaments. The stamens are 

 at first erect, but afterwards bend back towards the petals, giving free access to 

 the stigma, so that small insects covered with pollen are able to effect crossing. 

 Self-pollination is not excluded, but its effect is doubtful. 



503. C. sibirica Pall. — Agrees with the last species (Willis, op. cit.). 



