. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . ormed an open net-work ofbranches bound together by tenacula at thepoints of contact. As in other genera of theSiphonocladea3, there are numerous decumbentcreeping filaments attached to the substratum byrhizoids, and from them the erect leafy shootsarise. In Gkamtedoris the stipe is 4 or 5 cms. inlength, with annular constrictions from base toapex, where it terminates in a cup-shaped head,about 3 cms. in diameter, composed of large num-bers o
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . ormed an open net-work ofbranches bound together by tenacula at thepoints of contact. As in other genera of theSiphonocladea3, there are numerous decumbentcreeping filaments attached to the substratum byrhizoids, and from them the erect leafy shootsarise. In Gkamtedoris the stipe is 4 or 5 cms. inlength, with annular constrictions from base toapex, where it terminates in a cup-shaped head,about 3 cms. in diameter, composed of large num-bers of whorled branches of several orders, allarising by segregative cell-divisions. The branches are felted together andtheir coherence is increased by small rhizoids (tenacula) growing out hereand there and firmly attaching themselves to neighbouring filaments. In all the Siphonocladese there are numerous small plate-like polygonalchloroplasts, many of which contain a central pyrenoid. Very often, but notalways, the chloroplasts are connected by fine prolongations from theircorners, so that in each coenocyte there is apparently a net-like chloroplast. a Fig. 164. Siphonocladus tropicus(Crouan) J. Ag. x 15 (afterBorgesen). a, laterally branchedshoot, the basal part marked *.Only one branch is , appearance presented byseptate branch after soaking inglycerin. 256 Siphonoclad tales with many pyrenoids. Internal to the chloroplasts there are numerous andvery evenly distributed nuclei. Starch-grains are also present, but they aremore particularly accumulated in the rhizoids. Zoogonidia may arise in any of the branch-segments, the zoogonidangiumconsisting of the original coenocyte of the mother-branch and the branchgrown out from it but not yet cut off by a wall. The zoogonidia escape throughseveral orifices which are slightly protuberant, and they germinate directly.
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