. Plant studies; an elementary botany. Botany. 328 PLANT STUDIES gated, and is usually covered by a delicate flap {inr/iixiiiiii) wliieli arises from the epidermis (Fig. 290). Occasionally the sori are extended along the under surface of the mar- gin of the leaf, as in maidenhair fern [Adiaiiliiiii)^ and the common brake (I'lerix), i\i which case they are pi'otected l)y the inrolled margin (Fig. 398), which may be called a " false ; It is evident that such leaves are doing two distinct kinds of work—chlorophyll work and spore formation. This is true of most of the ordinary
. Plant studies; an elementary botany. Botany. 328 PLANT STUDIES gated, and is usually covered by a delicate flap {inr/iixiiiiii) wliieli arises from the epidermis (Fig. 290). Occasionally the sori are extended along the under surface of the mar- gin of the leaf, as in maidenhair fern [Adiaiiliiiii)^ and the common brake (I'lerix), i\i which case they are pi'otected l)y the inrolled margin (Fig. 398), which may be called a " false ; It is evident that such leaves are doing two distinct kinds of work—chlorophyll work and spore formation. This is true of most of the ordinary Ferns, hut some of them show a tendency to divide the work. Certain leaves, or certain leaf-branches, produce spores and do no chlorophyll work, while others do chloro- phyll work and produce no S2)ores. This differentiation in the leaves or leaf-regions is in- dicated by a2i2)roi)riate names. 'J'hose leaves which produce only spoi'cs are called sjjoro- pJiylls, meaning " spore leaves,'' while the leaf branches thus set apart are called sporophyll branches. Those leaves whidi only do cldoroi)hyll work are called foJidfje lea res ; and such branches are foliage branches. As sporo]>hylls are not called u]ion for chlorophyll work they often liecome much modifii'd, being much more compact, and not at all resembling the foliage leaves. Such a differ- entiation may be seen in the ostrich fern and sensitive fern (O/iiifh'ii) (Fig. '.'DOI, the climbing fern { Li/r/nfliinn), the royal fern {Oxmiiluhi), the nioonwort {/Idfri/fln'inii) (Kig. 300), and the adder's tongue {()/i/ii(i(/I(ixsinii).. Fro. 398. nf two roTmnnn fi^rns : .1, the common bi'ake iPlfvU): Tt. maif]PTib:lir {Adiaii- finn)\ botli piinwinLT ^'ori liornr' at the inarL'iii and liy the infold.'d iiiaTL'in. thus forms a false indnsiinii. - Cald- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an
Size: 1354px × 1845px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1900
