394 



VASCULAR CRYPTOGAMS. 



prothallia are larger (as much as ^ inch) ; Hofmeister compares them to the thallus 

 of Anthoceros punctatus, Duval-Jouve to a curled endive-leaf. Duval-Jouve states 

 that the antheridia appear about five weeks after germination, the archegonia much 

 later. These statements refer especially to JE. arvense, limosum, and palustre ; 

 according to the same writer, the prothallia of E. Telmaleia and sylvaticum are 

 broader and less branched; those of E. ramosissimum and variegatum slenderer 

 and more elongated. 



The Antheridia^ arise at the end or margin of the larger lobes of the male 



Fig. 275. — A male prothallium oi Equisetum arvense WxXkv 

 the first antheridia a (after Hofmeister, X 200) ; B—E anthero- 

 zoids oiE. Telmateia (after Schacht). 



Fig. 276.— Lobe of a highly developed female prothallium oi Eguisettim arvetise cut through vertically (after Hofmeister, 

 X about 60) ; a « a two abortive and one fertilised archegonium, h root-hairs. 



prothallium. The apical cells of the enveloping layer of the antheridium contain 

 but little or no chlorophyll; they separate from one another on the addition of 

 water (like those of Hepaticae), to allow the escape of the antherozoids, which are 

 still enclosed in vesicles and number from loo to 150. The hindermost and 

 thickest of the two or three coils of the antherozoid, which is larger in this class 

 than in all other Cryptogams, bears an appendage on the inner side which 



* [Sadebeck, Ueb, die Antheridien-Entwickelung der Schachtelhalme Sitzber. d. Gesellsch. 

 naturfor. Freunde zu Berlin, 1875.] 



