174 ANGIOSPERMAE—DICOTYLEDONES 



The small flowers are usually but slightly conspicuous, even when aggregated 

 into inflorescences. The polysepalous calyx permits the petals to spread out. This 

 takes place in the sunshine, the nectar secreted in the base of the flower at the same 

 time becoming visible, so that the Alsineae all belong to Class EC. The nectar is 

 therefore accessible to insects with a very short proboscis ; flies and the less special- 

 ized bees have chiefly been observed as visitors. Many Alsineae are dichogamous, in 

 which case they are almost always protandrous, but sometimes protogynous. Homo- 

 gamy is less frequent. The degree of dichogamy is proportionate to the conspicuous- 

 ness of the flowers and the number of insect visitors. Automatic self-pollination is 

 probably possible in all species, but is more certain in its action when the flowers are 

 inconspicuous, and insect visits few, either on this account or owing to unfavourable 

 weather. 



Schulz (' Beitrage,' I, pp. 25-6), adds the following particulars. — In many cases 

 the normal number (ten) of stamens is not developed. In certain species (Spergularia 

 salina Presl, Holosteum umbellatum Z., Cerastium semidecandrum Z., [also C. 

 tetrandrum Curi.'^ the full number is never or rarely present ; in others (Sagina 

 Linnaei Presl, Stellaria media Cyrill.) this is more frequently the case. In most 

 instances several, or all, of the inner stamens disappear, while even some of the 

 outer ones do so ; e. g. Spergularia salina, Holosteum umbellatum, and Stellaria media 

 commonly possess but three outer stamens. Vestiges of the filaments are usually 

 retained, and commonly small anthers devoid of pollen ; more rarely the stamens 

 have completely disappeared. In most species purely female stocks occur, often in 

 great numbers, but sometimes sporadically. In certain species hermaphrodite and 

 female flowers are found on the same plant. Male flowers have not been recorded. 

 The female flowers are usually at once distinguishable by their smaller size. Among 

 small-flowered species, female stocks are much less frequent than among large-flowered 

 ones. In several species where some of the stamens are almost always aborted — 

 it may be even some of the outer ones — female flowers are rare. There are both 

 individual species possessing small flowers — and therefore attracting insects but little 

 — which are protandrous, and large-flowered species that are homogamous. On the 

 whole, however, the small-flowered species are either homogamous or but slightly 

 protandrous. 



With regard to the development of the reproductive organs, and so forth, Schulz 

 (Beitrage,' II, pp. 52-5) speaks somewhat as follows. — 



The anthers of the outer stamens usually dehisce very soon after the flower 

 opens, their filaments, in many species, bending inwards, and frequently meetin" 

 above the ovary. Sooner or later, after the dehiscence of the outer anthers, those of 

 the inner stamens, of which the filaments are either erect or else more or less inclined 

 towards the petals, also begin to shed their pollen. At this time the outer anthers 

 in some species still contain abundant pollen ; in other species they are almost or 

 entirely empty; and in yet other species, e.g. in Alsine vema, some or all of them 

 have dropped off. There are but a few species in which both sets of anthers dehisce 

 simultaneously. The anthers of the same whorl dehisce either altogether or within 

 a short time — usually only a few minutes— of one another. In the latter case no 

 species exhibits any definite order. The anthers at first have an introrse position, 

 but in most species, either before or during dehiscence, or rarely towards its end, 



