(5) I. N. WILLIAMS. ON THE GENUS ARENARIA I.INN. 597 



Geographica range. Arenaria is a genus which includes plants of 

 wide distribution l><>th as regards latitude and altitude, chieflj confined to 

 the Dorth lemperate /.nue; within the arctic circle extending beyond the 

 limite of permanent human habitations, and m the tropicsonlj found m 

 elevated localities in mountainous districts, lu theold world species occur 

 en » I n in the northern hémisphère 1 , and the range of thé genus is from 

 tlie island of Novaya Zemlya in th<» Arctic sea (A. ciliata) to the Nilghiri 

 mountains in Malabar (A. nilghirensis). In the new world, there are seve- 

 ral species in North America and a few exlend as far south as Chile and 

 Argen tina. The genus is not represented in Auslralia. Several American 

 species hâve heen inadequately described, whose identification from dried 

 spécimens which hâve lain long in herbaria is unsalisfaclory ; luit some 

 of them from their habit and appearance might more thaï» doublfulh be 

 referred to Alsine, Stellaria, and probably also Colobunthiis. 



II. Conspectus subgenerum et sectionum. 

 ARENARIA 



Unn. Gen. Plant, éd. 1 (1737), p. 133, n. 374; éd. i. (1742), n. 146; 

 Syst. Nal. éd. (> (1748). n. 44«; Sp. Plant, éd. 1 (1753), p. 123; Gen. Plant, 

 éd. 5 (1754). n. 505; éd. (i (1764), n. 569; ex emend. Fenzl in Endl. (îen. 

 Plant., p. '.Ki7. n. 5234; etiam Ledeb. FI. Rossica I. p. 3(50: Engl, et Prantl, 

 Natûrl. Pflanzenf. III. pi. 1 b, p. 84 (1889) : c-haracteribus autem a prioribus 

 auctoribus definitis hoc in conspeclu paullo mulatis. 



Calyx 5-sepalus; sepala 5, imà basi connata. Petala 5, intégra, apice 

 rotundata oblusa retusa vel emarginata, rarius erosa vel laciniata; inter- 

 dum nulla. S ta mina 10. rarius 5. Discus perigynus, staminifer; nuncannu- 

 laris, glandulis inconspicuis vel obsoletis in discum immersis, nunc 5- vel 

 10-lobatus in glandulas prominentes expansus; hinc inde glandula» aut 5 

 staminiferœ aul 10 inter stamina sitae rarius staminiferae, membranaceae 

 vel carnosas, rotundata? vel bigibbosse. Gynœcium meiomerum. Ovarium 

 uniloculare; styli 3 vel 2 i interdum ii» nonnullis floribus 4-5), a basi dis- 

 tincli. Capsula globosa ovoidea breviter oblonga vel rarissime cylindrico- 

 conica. interdum depressa. primi'im dentibus duplo style. nun numéro 

 dehiscens, demùm in valvas 3 vel 2 bidenlalas interdum longitudinaliter 

 fissas secedens. Semina eslrophiolata nuda, reniformi-globosa vel a latere 

 compressa, undique tuberculata scabra laevia vel laevissime nitida. 



1 The S. African A. glandulosa of Jacquin belongs to SpergnJaria. 



