Difference between revisions of "Achnatherum ×bloomeri"

(Bol.) Barkworth
Synonyms: ×stiporyzopsis bloomeri unknown Oryzopsis ×bloomeri unknown Stipa bloomeri unknown
Treatment appears in FNA Volume 24. Treatment on page 142.
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|name=×stiporyzopsis bloomeri
 
|name=×stiporyzopsis bloomeri
 
|authority=unknown
 
|authority=unknown
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}} {{Treatment/ID/Synonym
 
|name=Oryzopsis ×bloomeri
 
|name=Oryzopsis ×bloomeri
 
|authority=unknown
 
|authority=unknown
}}{{Treatment/ID/Synonym
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}} {{Treatment/ID/Synonym
 
|name=Stipa bloomeri
 
|name=Stipa bloomeri
 
|authority=unknown
 
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|distribution=Colo.;N.Mex.;Utah;Calif.;Oreg.;Wyo.;Mont.;Wash.;Ariz.;Idaho;Nev.
 
|distribution=Colo.;N.Mex.;Utah;Calif.;Oreg.;Wyo.;Mont.;Wash.;Ariz.;Idaho;Nev.
|discussion=<p>Achnatherum ×bloomeri and other hybrids involving A. hymenoides</p><!--
+
|discussion=<p><i>Achnatherum ×bloomeri</i> and other hybrids involving <i>A. hymenoides</i></p><!--
--><p>Numerous natural hybrids exist between Achnatherum hymenoides and other members of the Stipeae. Johnson (1945, 1960, 1962, 1963, 1972) described several of these; all are sterile. Using the treatment adopted here, Johnson's hybrids have as the second parent A. occidentale (all subspecies), A. thurberianum, A. scribneri, A. robustum, Jarava speciosa, and Nassella viridula. Evidence from herbarium specimens suggests that A. hymenoides also forms sterile hybrids with other species of Achnatherum. The name Achnatherum ×bloomeri applies only to hybrids between A. hymenoides and A. occidentale subsp. occidentale, but plants keying here may include any of the other interspecific hybrids. They all differ from A. hymenoides in having more elongated florets and awns 10-20 mm long, and from their other parent, in most instances, in having longer lemma hairs and more saccate glumes. Identification of the second parent is best made in the field by noting which other species of Stipeae are present, bearing in mind that species that are not in anthesis at the same time in one year might have sufficient overlap for hybridization in other years.</p><!--
+
--><p>Numerous natural hybrids exist between <i>Achnatherum hymenoides</i> and other members of the Stipeae. Johnson (1945, 1960, 1962, 1963, 1972) described several of these; all are sterile. Using the treatment adopted here, Johnson's hybrids have as the second parent <i>A. occidentale</i> (all subspecies), <i>A. thurberianum</i>, <i>A. scribneri</i>, <i>A. robustum</i>, <i>Jarava speciosa</i>, and <i>Nassella viridula</i>. Evidence from herbarium specimens suggests that <i>A. hymenoides</i> also forms sterile hybrids with other species of <i>Achnatherum</i>. The name <i>Achnatherum ×bloomeri</i> applies only to hybrids between <i>A. hymenoides</i> and <i>A. occidentale </i>subsp.<i> occidentale</i>, but plants keying here may include any of the other interspecific hybrids. They all differ from <i>A. hymenoides</i> in having more elongated florets and awns 10-20 mm long, and from their other parent, in most instances, in having longer lemma hairs and more saccate glumes. Identification of the second parent is best made in the field by noting which other species of Stipeae are present, bearing in mind that species that are not in anthesis at the same time in one year might have sufficient overlap for hybridization in other years.</p><!--
--><p>Of the two intergeneric hybrids mentioned above, that with Nassella viridula is treated as ×Achnella caduca (see p. 169). It differs from Achnatherum hymenoides in its longer glumes and florets, and from other A. hymenoides hybrids in having a readily deciduous awn. No binomial has been proposed for the hybrid with Jarava speciosa. There is one fertile intergeneric hybrid involving A. hymenoides, A. contractum. It is included in Achnatherum and described below because it resembles other members of Achnatherum more than it does Piptatherum, the genus of the other parent.</p><!--
+
--><p>Of the two intergeneric hybrids mentioned above, that with <i>Nassella viridula</i> is treated as ×Achnella caduca (see p. 169). It differs from <i>Achnatherum hymenoides</i> in its longer glumes and florets, and from other <i>A. hymenoides</i> hybrids in having a readily deciduous awn. No binomial has been proposed for the hybrid with <i>Jarava speciosa</i>. There is one fertile intergeneric hybrid involving <i>A. hymenoides</i>, <i>A. contractum</i>. It is included in <i>Achnatherum</i> and described below because it resembles other members of <i>Achnatherum</i> more than it does <i>Piptatherum</i>, the genus of the other parent.</p><!--
--><p>Sterile hybrids have anthers that do not dehisce, and contain few, poorly formed pollen grains. They also fail to form good caryopses, but this is also true of some non-hybrid plants. In the case of non-hybrid plants, failure to form good caryopses can result from failure to capture pollen or from incompatibility between the pollen grain and the pistillate plant. It is not known which, if either, of these explanations accounts for the large number of empty caryopses found in Achnatherum hymenoides.</p>
+
--><p>Sterile hybrids have anthers that do not dehisce, and contain few, poorly formed pollen grains. They also fail to form good caryopses, but this is also true of some non-hybrid plants. In the case of non-hybrid plants, failure to form good caryopses can result from failure to capture pollen or from incompatibility between the pollen grain and the pistillate plant. It is not known which, if either, of these explanations accounts for the large number of empty caryopses found in <i>Achnatherum hymenoides</i>.</p>
 
|tables=
 
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|references=
 
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|publication year=
 
|publication year=
 
|special status=
 
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/9216fc802291cd3df363fd52122300479582ede7/coarse_grained_fna_xml/V24/V24_190.xml
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|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/8f726806613d60c220dc4493de13607dd3150896/coarse_grained_fna_xml/V24/V24_190.xml
 
|subfamily=Poaceae subfam. Pooideae
 
|subfamily=Poaceae subfam. Pooideae
 
|tribe=Poaceae tribe Stipeae
 
|tribe=Poaceae tribe Stipeae

Revision as of 16:18, 18 September 2019

Please click on the illustration for a higher resolution version.
Illustrator: Cindy Roché

Copyright: Utah State University

Distribution

Colo., N.Mex., Utah, Calif., Oreg., Wyo., Mont., Wash., Ariz., Idaho, Nev.

Discussion

Achnatherum ×bloomeri and other hybrids involving A. hymenoides

Numerous natural hybrids exist between Achnatherum hymenoides and other members of the Stipeae. Johnson (1945, 1960, 1962, 1963, 1972) described several of these; all are sterile. Using the treatment adopted here, Johnson's hybrids have as the second parent A. occidentale (all subspecies), A. thurberianum, A. scribneri, A. robustum, Jarava speciosa, and Nassella viridula. Evidence from herbarium specimens suggests that A. hymenoides also forms sterile hybrids with other species of Achnatherum. The name Achnatherum ×bloomeri applies only to hybrids between A. hymenoides and A. occidentale subsp. occidentale, but plants keying here may include any of the other interspecific hybrids. They all differ from A. hymenoides in having more elongated florets and awns 10-20 mm long, and from their other parent, in most instances, in having longer lemma hairs and more saccate glumes. Identification of the second parent is best made in the field by noting which other species of Stipeae are present, bearing in mind that species that are not in anthesis at the same time in one year might have sufficient overlap for hybridization in other years.

Of the two intergeneric hybrids mentioned above, that with Nassella viridula is treated as ×Achnella caduca (see p. 169). It differs from Achnatherum hymenoides in its longer glumes and florets, and from other A. hymenoides hybrids in having a readily deciduous awn. No binomial has been proposed for the hybrid with Jarava speciosa. There is one fertile intergeneric hybrid involving A. hymenoides, A. contractum. It is included in Achnatherum and described below because it resembles other members of Achnatherum more than it does Piptatherum, the genus of the other parent.

Sterile hybrids have anthers that do not dehisce, and contain few, poorly formed pollen grains. They also fail to form good caryopses, but this is also true of some non-hybrid plants. In the case of non-hybrid plants, failure to form good caryopses can result from failure to capture pollen or from incompatibility between the pollen grain and the pistillate plant. It is not known which, if either, of these explanations accounts for the large number of empty caryopses found in Achnatherum hymenoides.

Selected References

None.

Lower Taxa

None.