5o6 ANGIOSPERMAE—MONOCOTYLEDONES 



are irregularly expanded. The upwardly tapering filaments bear inverted anthers, 

 which contain smooth, easily scattered pollen. The stigma forms a bipinnate brush 

 with long, transparent papillae, and springs from a little below the tip of the ovary. 

 The stigma no doubt matures before the anthers. 



964. Triglochin Riv. 



Literature. — Axell, ' Om Anord. for Fanerog. Vaxt. Befrukt.,' p. 38 ; Knuth, 

 ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 135-6 ; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, 

 p. 148 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 291. 



Protogynous wind flowers. The hexaphyllous calyciform perianth serves as 

 a temporary receptacle for pollen falling from the stamens situated above. The 

 anthers of the lower staminal whorl dehisce first, and then those of the upper one. 

 Kerner says that the stigmas mature 2-3 days before the anthers. 



2947. T. maritimiim L. (Knuth, loc. cit.) — During the first stage of anthesis 

 in this species the somewhat pinnate papillose stigmas protrude from the perianth 

 leaves, which at first still remain closed like a bud. The latter are carinate in form, 

 and greenish in colour with reddish tips; later on they are forced apart by the 

 swelling of the ovary, and the three sepals bend slightly backwards, but in such 

 a way that their tips, which gradually become brown in colour, always remain in 

 contact with the ovary. In this way three crescentic pockets are formed, behind 

 each of which an anther dehisces, part of the pollen falling into it. On being lightly 

 touched, and by every gust of wind, the pollen is scattered from the pockets and 

 also from the anthers if they still contain any. The sepals, which have become dry 

 and skin-like, become loose, and are carried away by gusts of wind with the pollen 

 lying in them and the anthers united to their bases. When the calyx has been 

 removed in this manner the same process takes place with the corolla. Warnstorf 

 describes the pollen-grains as yellowish-white in colour, very irregularly tetrahedral, 

 tuberculate, 25-31 fx in diameter. 



2948. T. palustre L. (Knuth, op. cit., p. 136.) — This species possesses the 

 same flower mechanism as the preceding one. Warnstorf describes the pollen-grains 

 as whitish in colour, spheroidal to ovoid, closely tuberculate, 31 jix in diameter on an 

 average. 



A very delicate small-flowered variety of this species, with slender stems, occurs 

 in Greenland (Abromeit, 'Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 78). 



965. Potamogeton L. 



Literature. — Axell, ' Om Anord. for Fanerog. Vaxt. Befrukt.,' p. 38 ; MacLeod, 

 Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 283-5; Knuth, ' Bl. u. Insekt. a. d. 

 nordfr. Ins.,' pp. 136-7. 



Aquatic plants bearing protogynous, anemophilous, hermaphrodite flowers. 

 Perianth absent, but replaced by four scale-shaped connectives. Kerner states that 

 the pollen falls first of all into a cavity in the connective (at any rate in P. crispus L.). 



