VASCULAR CRYPTOGAMS. ^^g 



(i) Filices or Ferns. Prothallium above-ground, green, monoecious; branching of 

 the stem probably at first dichotomous ; exogenous adventitious buds formed on 

 the leaves ; the sporangia are trichomes of the leaves, which are stalked, usually 

 large and branched, and are characterised by the long continuance of their 

 apical growth. 



(2) Equisetaceee. Prothallium above-ground, green, monoecious or dioecious; 

 branching of the stem exclusively by endogenous verticillate lateral buds; 

 leaves very simple, verticillate, forming sheaths; the sporangia are produced 

 in groups on the margin of metamorphosed leaves, and constitute a terminal 

 fructification. 



(3) Opbioglojsacecs. Prothallium underground in the two known cases, not green, 

 monoecious; the stem has apparently no provision for branching; the leaves 

 have a stalked lamina and a sheathing base ; the sporangia are produced on a 

 branch of the leaf, and constitute a spike or panicle. 



II. Heterosporous Vascular Cryptogams. 



INTacrospores and microspores are produced; the macrospore produces the female 

 prothallium and nourishes it, the prothallium never becoming independent ; the micro- 

 spores produce a rudimentary prothallium which does not become free, and in which 

 the antherozoids are formed. 



(4) Rbizocarpecp. The female prothallium protrudes from the cavity of the spore, 

 and remains attached by its lower side to the macrospore; its size is less 

 than that of the spore ; the sporangia are produced in numbers in the interior 

 of hollow receptacles (sporocarps), and produce either a single macrospore or 

 a number of microspores ; the sporocarps are appendages of the leaves. 



(5) Lycopodiacea;. INIacrospores are known to occur only in two sections, the 

 Selaginellcas and IsoetCcT ; the prothallium in these cases fills the cavity of the 

 macrospore, and only the part which bears the archegonia protrudes; the 

 terminal branching of the stem is dichotomous, or there is no provision for 

 branching (Isoetes); the sporangia are produced singly on the upper side of 

 the leaves near their base ; the macrosporangia produce a few macrospores, the 

 microsporangia a large number of microspores. 



z 2 



