1 6 The Ohio Naturalist. [Vol. VII, No. 1, 



25. Perithecia inclined or horizontal, the ostioles usually opening into a 

 common canal; situtited in a stroma; algal cells Chroolepus. 



ASTROTHELIACEAE. 



25. Perithecia erect -with a single ostiole at the summit. 26. 



26. Perithecia in a stroma; algal cells belonging to Clroolepus. 



Trypetheliaceae. 



26. Perithecia single; storma wanting. 27. 



27. Spores one-celled (in our species); algae belonging to Pleurococcus 



or Palmella. Verucariaceae. 



27. Spores one to multiseptate (in our species); algal cells belonging to 



Chroolepus. Pvren'ULaceae. 



PUBESCENCE AND OTHER EXTERNAL PECULIARITIES OF 



OHIO PLANTS. 



EoxA IM. McCleerv. 



In this study of the protective coverings and other peculiar- 

 ities of the leaves and twigs of Ohio plants, the entire state her- 

 barium has been examined and the plants classified under the 

 following heads: 



1. Pubescent — (a) glandular, (b) stellate, (c) tomentose; 



2. Glabrous; 



3. Glaucous; 



4. Granular; 



5. Scurfy ; 



6. Resin dotted, punctate, peltate scales. 



In some cases it has been difficult to classify certain species 

 on account of manv of the forms merging almost imperceptibly 

 from one to another. This is noticeable especially in pubes- 

 cent and tomentose forms. In other cases the difficulty in class- 

 ification has come from the change which takes place during de- 

 velopment from the young to the mature condition. 



In Salix Candida, for instance, the leaves are loosely tomen- 

 tose when young, but become glabrate above when mature. In 

 Quercus nana the leaves are stellate pubescent above when young 

 but become glabrous when mature, while in Quercus minor the 

 young twigs are tomentulose but the mature ones glabrous. In 

 all cases of this kind the forms have been listed under two or 

 more heads. 



The entire number of reported Ohio vascular plants is about 

 2200. Of these about 2125 are angiosperms, 10 gymnospei^mes, 

 and 70 pteridophytes. 904 plants were found to be pubescent. 

 This includes all degrees and varities of pubescence from those 

 with only a soft fine pubescence like the clover and Oxalis to those 

 with heavy hairs like the nettles or thistles. For a dense velvety 

 pubescence of both twigs and leaves Althaea officinalis might be 

 examined; for hirsute pubescence of l:)oth twigs and leaves Ascle- 

 pias tuberosa is a good example; for soft downy ptibescence 



