CARYOPHYLLEAE 1 79 



MacLeod saw two hover-flies and a Muscid in Flanders (Bot. Jaarb. Dodonaea, 

 Ghent, vi, 1894, p. 158). 



In Dumfriesshire an Empid, three Muscidae, and five hover-flies have been 

 recorded (Scott-Elliot, ' Flora of Dumfriesshire/ p. 31). 



445. S. pentandra L. — According to Schulz (' Beitrage,' II, p. 41), the flowers 

 of this species are open from noon till 5 p.m. They are homogamous, and, as 

 a rule, only five stamens are present. These are usually erect in the open flower, or 

 spread somewhat outwards, so that the anthers do not generally come into contact 

 with the stigma. As the flowers, however, soon close and in dull weather do not 

 open at all, automatic self-pollination takes place, while in the open flowers cross- 

 pollination is favoured by insect-visits. In addition to hermaphrodite flowers female 

 ones sometimes occur, these being distributed gynomonoeciously or gynodioeciously. 



446. S. Morisonii Bor. (=S. vernalis Willd., in part). — Schulz states 

 (' Beitrage,' II, pp. 39-41) that the hermaphrodite flowers of this species are homoga- 

 mous in North Thuringia, but when the flowers are open — between noon and 5 p.m. — 

 the anthers do not usually touch the stigmas. Of the ten stamens a few are com- 

 monly vestigial, and sometimes none are developed, so that the flowers become 

 female. Such female flowers are smaller than the hermaphrodite ones, and are 

 distributed either gynomonoeciously or gynodioeciously. Cross-pollination is favoured 

 by insect-visits, but automatic self-pollination takes place when the flowers close. 

 Warnstorf (Verb. bot. Ver., Berlin, xxxviii, 1896) observed only homogamous and 

 autogamous hermaphrodite flowers at Ruppin. 



128. Spergularia Presl. 



Flowers white or red, varying from marked protandry to homogamy, with nectar 

 half concealed. 



447. S. media Poir. (= S. marginata Kitt., and Arenaria marginata DC-). — 

 Schulz states that the red or white hermaphrodite flowers of this species are distinctly 

 protandrous at Halle. All ten stamens are usually developed. Besides hermaphrodite 

 flowers, smaller female ones have been occasionally observed — e. g. by MacLeod on 

 the Belgian coast — and the plants in such cases are gynodioecious, more rarely 

 gynomonoecious. 



Visitors. — I observed small Diptera — sp. of Hilara and Hydrellia— in the 

 Halligen. 



448. S. salina Presl (= Arenaria rubra (3 marina Z., S. marina Griseb., Arenaria 

 marina Roth, and Lepigonum medium Wahlenb). — The flowers of this species 

 investigated by MacLeod on the Belgian coast were very similar to the female flowers 

 of the last species. The petals are rose-red ; only 1-3 stamens are developed ; 

 automatic self-pollination is ensured. 



Schulz examined the flowers by the Salt Lake at Eisleben, where they appear 

 to be considerably smaller than in Belgium. The petals are shorter than the sepals ; 

 frequently but three stamens are developed, which usually mature rather sooner than 

 the stigmas, these being at the same level. The nectar is secreted by a fleshy ring 

 internal to the bases of the stamens. In unfavourable weather the flowers remain 

 closed, so that automatic self-pollination necessarily takes place. 



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