. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. EPIDERMIS. 53 MoUugo and Rubia tinctorum have practically no air-pores on the upper side, at the apex they have a group of vpater-pores. In Papaver orientale, somniferum, and other species, 2-3 large pores lie in a small cowl-like depression on the under side of the teeth of the leaf. Tropaeolum majus, Lobbianum and other species have over each nerve-ending at the margin of the peltate leaf one very large water-pore, near this 2-3 or 4-5 (Tr. Lob- bianum) additional ones v>?hich are rather sm
. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. EPIDERMIS. 53 MoUugo and Rubia tinctorum have practically no air-pores on the upper side, at the apex they have a group of vpater-pores. In Papaver orientale, somniferum, and other species, 2-3 large pores lie in a small cowl-like depression on the under side of the teeth of the leaf. Tropaeolum majus, Lobbianum and other species have over each nerve-ending at the margin of the peltate leaf one very large water-pore, near this 2-3 or 4-5 (Tr. Lob- bianum) additional ones v>?hich are rather smaller (Fig. ig). I have not found the pores described by Mettenius and Rosanoff on the callous middle portion of the leaf. Nelumbium speciosum has a group of several pores in the last-named spot. Among submerged water plants we know from Borodin that in Callitriche verna one large open pore lies over the end of the vascular bundle, on the upper surface of the leaf. In Callitriche autumnalis there lie at the same spot on the young leaf a group of 3-8 open stomata; in the mature leaf the guard-cells of these break down, so that there remains a wide hole in the epidermis. In Callitriche verna also this phenomenon ap- pears in the older leaf: nevertheless I found the guard-cells still intact on leaves several months old. The apices of the leaves of Hippuris behave similarly to those of Callitriche autumnalis (Borodin). On the segments of the young submerged leaves of Ranunculus aquatilis, divaricatus, Hottonia palustris, Askenasy' found several stomata, which die off with the whole apex before the complete maturity of the leaf. It is doubtful whether these belong to the category in question. Water-pores with a short slit are known in the case of a number of species of Crassula, and Rochea and many species of Saxifraga and Ficus with depressions on their leaves. The leaves of the above Crassulaceae ^ have round spots or depressions easily seen with the naked eye, either on both surf
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
