128 



THE CRYPTOGAMIA OR FLOWERLESS PLANTS. 



550 a 



and discharcinir it* 



545 517 5 It) 549 



Seaweeds (Algas). 515, Vaucheria formin 

 spores («) at tho extremities. 546, Fucus; «, air-vessel; b. fruit, 

 a mass of concptacles. 547, Transverse section of a conceptaclo. 

 548, A spore with paraphascs. 549, Hydrogastrum, consisting of a 

 single cell. 550, Spirogyrae (Frogspittle) one of the Confervas ; a, 

 two threads (tballi) conjugated, i. e., united by tubes. 



such sporiferous tissues existing in 

 spots of definite form, constitute the 

 apothecia when flat, receptacles when 

 concave, and conceptaclcs when hol- 

 low. 



632. The tiiecje or sporangia of 

 ferns and mosses consist of tissues 

 rather than of single cells, and contain 



division of the Cryp- 

 togams into the En- 

 pores and tho 

 Exospores. In tho 

 latter case the pa- 

 rent-c^lls are called 

 basidia, and many 

 such united, as iu 

 the lichens and 

 mushrooms, form a 

 tissue called hyme- 

 nium. In lichens 



551, Frustules of a Diatomaceous Alga 

 (Diatoma marinuin) separating from each 

 other. 



Lichens, 530, Cladonia ; the minute thallus at the base of the podetia, cup-like above, bearing 

 scarlet conceptaclcs. 531, Usnea. 532, Sticta. 533, Paralalia. 534, Receptacle, vertical seo- 

 tion. 535, A portion (highly magnified) with thecas and paraphascs. 536, A spore (doublo). 



numerous spores. In ferns they grow on the hack of the fronds in 

 little clusters called sori. When mature, the sporange is torn open hy 

 the contraction of an clastic ring which surrounds it. In the mosses 

 tho sporange is stalked, solitary, terminal, and opens hy a definite num- 

 ber of teeth called the peristome. 



633. Zoospores and spermatozoids arc minute bodies endowed with 

 spontaneous locomotion in water by means of vibratile cilia. Zoospores 

 of ovate form proceed from the vegetative cells of the Algae, swim 

 about for a time, then settle down and grow into new plants. Sperma- 

 tozoids are mostly filiform bodies with several ciliae, discharged from the 



