380 



BOTANY. 



The stems are developed from a triangular apical cell, while the 

 roots, like those of Marattiacece, possess no apical cell, but a group 

 of cells instead. The tibro-vascular bundles are arranged in a cylinder 

 (a circle in cross-section), and they form a network by their anastomos- 

 ing with each other. According to De Bary, they belong to the "col- 

 lateral " series. 



These plants are usually of small size, rarely exceeding 30 centime- 



<s^ 

 <8>, 



B 



Fig. 271. A, vertical section of an archogoninm and the rudimentary prothallium 

 of Pilvlaria globulifera ; tv, w, part of the ruptured wall of the macrospore ; p, p 

 the rudimentary prothallium. merging above into the archegoninm ; a, the germ-cell 

 ready for fertilization ; c. the cavity of the macrospore. X 500. B. a microspore 

 of the same hurst open and allowing the escape of sperm-cells. . from which sper- 

 matozoids are escaping. X 600. C , longitudinal section of n macrospore of Salrin'm 

 natana at the commencement of germination ; p. the young protlmllium. x 30. D, 

 a very young prothallinm of the same, detached, with a fragment of the inner spore- 

 membrane (m) adhering to it top view. X 2(0. E, a vertical longitudinal section of 

 D. X 200. F a similar section of a more advanced prothallium of the same ; g. the 



. 



young germ-cell. X 200. G, vertical section of an unfertilized archegonium of the 

 same, surrounded hy cells of the prothallium ; g, germ-cell ; ar, canal of the arche- 

 gonium. x 300. After Hofmeister. 



tres (1 foot) in height ; in one Ceylonese species (Ophioglo&sum pendu- 

 lum) the slender pendent leaves are sometimes, according to Hooker, 

 nearly three metres long (15 feet). 



There are three genera, viz., Ophiofflossxm, JtotryeJiium, and Helmin- 

 ; the latter is confined to the southern hemisphere, the others 



(J. E. Davenport's paper, Verimtimt in l!trt/<-hi<i. in the bulletin of 

 t/u 'I'urrey Botanical Club, 1878; it is illustrated by figures. 



