. Heredity and evolution in plants . 13.—Types of fern sporangia. A, Loxsoma Cunninghami; B,Gldchenia circinata; C, Todca barbara; D, Thyrsoptcris elegans; E~,Matomapcctinala; F, Lygodium japonicum. (Redrawn from various, sources.) :« fessor Bower, of Glasgow, has called attention to this factin t^e following words: A rough estimate may be made of the numerical output of spores froma large plant of the Shield fern, as follows: In each sporangium 48spores may be formed; a sorus will consist of fully 100 sporangia, usuallymore; 20 is a moderate estimate of the sori on an average pinna; there may
. Heredity and evolution in plants . 13.—Types of fern sporangia. A, Loxsoma Cunninghami; B,Gldchenia circinata; C, Todca barbara; D, Thyrsoptcris elegans; E~,Matomapcctinala; F, Lygodium japonicum. (Redrawn from various, sources.) :« fessor Bower, of Glasgow, has called attention to this factin t^e following words: A rough estimate may be made of the numerical output of spores froma large plant of the Shield fern, as follows: In each sporangium 48spores may be formed; a sorus will consist of fully 100 sporangia, usuallymore; 20 is a moderate estimate of the sori on an average pinna; there maybe fully 50 fertile pinnae on one well-developed leaf, and a strong plantwould bear 10 fertile leaves. 48 X ico X 20 X 50 X 10 = 48,000, output of spores on a strong plant in the single season will thus, on amoderate estimate, approach the enormous number of fifty millions. 8. Types of Sporophylls - -In many ferns the leavesserve both vegetative and reproductive functions in about 1 Bower gives this number as the character
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