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ORTHOTRICHUM HALLII SULLIV. & LESQ. 



John M. Holzinger. 



Among some Wyoming mosses recently received from Professor Aven 

 Nelson for determination was an Orthotrichum which proved to be typical 

 O. Hallii. The plant was sent sub nuniero 125, and was collected by Mr. 

 Leslie Gooding on bare dry rocks '' in Platte Canyon, S. E. Wyoming. The 

 habitat at the type station (Rocky Mountains, E. Hall) is given as " on 

 trees." Yet there seemed little doubt, judging from both the description 

 and the plate in Sulliv. Icon. Muse. Suppl., t. 4s, that this rock moss was the 

 same species. So it was sent to Mrs. E. G. Britton for comparison with the 

 type, if possible. She sent it to the Harvard Herbarium. From there it was 

 learned that " the type is in poor condition, only old and incomplete capsules 

 left, without calyptras, lids or peristome," Mrs. Britton's suggestion that 

 "evidently SuUivant sent the best he had to his draughtsman" is but too true. 

 Under the circumstances it is of interest to find new material in as perfect 

 condition as is this from Wyoming. 



Through the mediation of Mrs. Britton I have been able to examine 

 closely a sterile stem from the Harvard type material. A comparison of 

 the leaf sections leaves no doubt whatever regarding this Idaho plant being 

 typical Orthotrichujn Hallii. The strong unbranched papillae, standing 

 over the lumen of the cells ; the two cell layers which begin below the leaf 

 middle, where they usually do not extend across the lamina, reaching to the 

 apex, where they are characteristic of the entire \&.n\\n2^\ these are charac- 

 ters exactly identical in the Wyoming and in type material. I therefore 

 have thought it proper to supplement Sullivant's illustrations of this beauti- 

 ful species by the accompanying figures of leaf sections, and also of the 

 upper part of the capsule, with part of the peristome. It will be observed by 

 comparing Sullivant's figure 10, representing the peristome with a part of the 

 mouth of the capsule, and the accompanying figure i, that an attempt has 

 been made in the latter to emphasize a second characteristic feature, namely 

 the five or six rows of roundish isodiametric cells at the mouth of the cap- 

 sule. These, as well as the three or four longitudinal rows of cells which 

 alternate with the eight pairs of teeth, assume a, darker yellow color than the 

 rest of the capsule. 



The material in hand shows a stage of the capsule not indicated in the 

 description and figures of this species. Several freshly deoperculate cap- 

 sules retained their bulging shape and their green color while dry, but were 

 even at this stage marked by eight strongly projecting costse or ridges. 

 These are omitted in Sullivant's figure 6; and comparing this with his figure 

 8, one is led to expect that these costse do not appear till the capsule assumes 

 the form shown in figure 8. The fragile whitish peristome stands erect as 

 given for the type, which causes the teeth to be easily broken; but occasion- 

 ally a tooth persists till old age, and then turns back against the capsule. 



It thus appears that this moss is well distinguished from all our North 

 American Orthotricha by its fruit as well as leaf characters; and where the 

 fruitis absent orimmature, the leaves alone are still sufficient for determina- 



