408 



THE BOOK OF CHOICE FERNS. 



a produced or condensed stem, so as to form a dense spike at the end of the 

 leafy branches. The microsporangia, which are by far the more plentiful, 

 contain numerous very minute, dust-like microspores. The macrosporangia, 

 Avhich contain four or fewer macrospores — much larger, globose, generally 

 chalk-white, and furnished with three ribs, which develop a minute female 

 prothallium, remaining permanently attached to the spore — are few and are 

 confined to the base of the spike. 



The name Selaginella is a diminutive of Selago, the old name for another 

 Lycopod. The genus is a very extensive one,, comprising upwards of 300 

 species of stove, ' greenhouse, and hardy, evergreen plants much resembling 

 mosses ; but, on account of the difficulties attending their importation and 

 the germination of their spores after a long journey, a great number of 

 them are not in cultivation. In his admirable work above quoted, Baker 

 divides the Selaginellas into six series as follow : 



I. Decumbentes (De-cum-ben'-tes). This is the most extensive series ; 

 it comprises dwarf species with the main stem decumbent and root-fibres 

 extending to its upper nodes. They may be (1) persistent species with leaves 

 of firm or moderately firm texture, continuous stems, and leafy branches, like 

 the Asiatic and European S. helvetica and the West Indian serpens ; or (2) 

 persistent species with articulated stems, such as the West Indian S, Martensii 

 stolonifera ; or (3) fugacious species— tropical annuals of the rainy -season — 

 with continuous stems such as the Asiatic S. nipponica or the American 

 S. apus. 



II. Ascendentes ( As-cen-den'-tes) . The plants forming this series have 

 ascending stems, branched to the base, with the root-fibres confined to the 

 nodes of the lower half. They may be (1) persistent species with continuous 

 stems and broad, leafy branches, such as the West Indian S. setigera, the 

 African S. Kalbreyeri, or the American S. Martensii; or (2) persistent species 

 with articulated stems, such as S. Galeottei ; or (3) fugacious species — tropical 

 annuals of the rainy season— with unjointed stems, such as S. Poulteri, 



III. RosuLATiE (Ros-ul-a'-ta)). In this series, the plants have their 

 stems densely tufted, curling up in drought, sometimes, but not always, 

 branched down to the base, the root-fibres being confined to the base. 

 S. involvens, of the Old World, and S. lepidojjhylla, of the New World, well 

 illustrate this series. 



