Wednesday, December 30, 2009

Angora and a Little Rascal

With the flowering of each new cross, I get more and more excited about the potential for hybridizing within the genus Petrocosmea! I often think back to what it must have felt like for those very first hybridizers of African violets and then reflect upon the myriad of flower and foliage variations available today within that genus. Looking at a collection of species Saintpaulia, one might never imagine the variety that would have evolved from those charming, but fairly simple and uniform flowers and foliage types among the species in that genus. Oh, the things that are yet to be within the world of Petrocosmea!!!!! ( I can dream, can't I???)

The subject of my current adoration is the offspring from a cross between P. forrestii (as the seed parent) and the magnificent, and quite unique P. duclouxii. Both very different from each other in a number of ways. I was on Cloud Nine when I saw those seedpods developing! Now, ten months later, the babies have grown up and are showing first flowers. I've selected two from among the twenty that I flowered to name,and one other one which is remaining unnamed for the moment. P. duclouxii was clearly dominant form flower type in every seedling. P. forrestii was dominant for foliage type among all but one of the seedlings. Flower size was a mixed bag, with about nine having smaller flowers like forrestii and 11 having larger flowers like duclouxii. Peduncle length was clearly influenced more by forrestii...which I was not so happy about. Now, here are the "kids"........

Petrocosmea 'Keystone's Angora' was the first selected and named. It was chosen for it's magnificent foliage, which appears as a large P. forrestii, but the leaf texture is outstanding. I wish you could touch the screen and feel these leaves! They are literally as soft as angora! I HAVE to pet them everytime I see this plant. Hence, the name! The plant is showing more buds to come. I'm hoping for a bit more bloom with maturity, since both parents are quite floriferous.

The flower of P. 'Keystone's Angora' ...a smaller version of it's P. duclouxii parent, but a bit pinker, due to the influence of forrestii. Petals are rounder and more obtuse on the tip, making the flower less "starry" than those of P. duclouxii. Anthers are deformed, producing no pollen, but the pistil appears normal. I'm hoping it will be seed-fertile.

The second seedling names is P. 'Keystone's Little Rascal'. Leaves are more like duclouxii in shape and texture, with some veining, but size of the foliage is more like forrestii. It was chosen for it's heavy flower count and small size. It was the only seedling to inherit the shorter, sturdier peduncles of P. duclouxii. All other seedlings have the long, unruly peduncles of P. forrestii...and undesirable trait in my opinion. This plant did form two offsets, which I was not happy about, however, it's positive qualities of heavy bloom count, peloric flowers, most with extra petals, and the sturdier peduncles won out. The flowers on this plant are quite small, among the smallest of all it's siblings. I'm happy with it's reduced size and compact habit.

Most of the flowers (92% of them) were near-peloric and had extra petals. Again, as with all of the flowers in this cross, the anthers are deformed and produced no pollen. Pistils appear normal.

One other trait from this cross which I was very happy about, was that it produced three very small, almost "miniature" seedlings. This is the third Petrocosmea cross, involving larger parents that has show a tendency to produce a few "miniatures". My first cross, P. rosettifolia #3 x sericea produced one miniature plant, which pure white flowers (P. 'Keystone's Bantam'). By using P. 'Kesytone's Bantam' in a cross with P. forrestii (the most compact of the species), I got 100 miniature seedlings...all MUCH smaller then 'Keystone's Bantam'. None of these have flowered yet, after 11 months, and most all are producing HEAVY offsets, a trait which I am attempting to select out of the hybrids that I release, so I am not sure that I will ever release any of these. These miniatures do, however, give great hope to me that miniature Petrocosmeas are a real possibility and likely not too far in the future. Just one more exciting and mysterious trait tucked away within the genetics of this genus.

A photo showing the difference in the size of the flowers of P. 'Keystone's Little Rascal' (on the right) and one of it's siblings....(which I have not named so far). Both of these are smaller than the parent P. duclouxii. Petal shape, petal width and length all were quite variable, as can also be seen in the photo The petals of the larger flower on the left are more oblong and narrow, giving the flower a more "star-like" appearance. The petals on 'KLR' on the right are shorter and more ovoid in shape, making the flower appear rounder and fuller.
And, as must be done, the remaining 17 seedlings all went into the trash bin...... Rest In Peace!

Monday, December 28, 2009

A "Child" Grows Up... Petrocosmea 'Rosemary Platz'

In a recent post, I promised that I would post a photo of my first named hybrid P. 'Rosemary Platz' as it came into full bloom this season. This was the hybrid that heralded the beginning of what has been an incredibly rewarding, enjoyable, and educational experience for me. It happened by accident, really.

A couple of years ago, after having tried for nearly ten years to get Petrocosmeas to set seed, I made yet another attempt. Due to impending long days and heavy weeks ahead with my shifts at work, I had placed several of my Petrocosmeas that were showing buds underneath a humidity dome in my basement light stands. In early October, two species were sitting side by side underneath one of those domes, and both were in flower. P. rosettifolia #3 and P. sericea. So, on a whim, I took the pollen from both flowers and made reciprocal crosses between the two species. I then put it out of my mind, assuming, as had always been the case, that both would fail. A month or so later, when I had a chance to check on my plants in between shifts, I noticed seedpods forming on both species!!! WHAT?!! It couldn't be! But, yes, there they were...five seedpods... three on the rosettifolia and two on the sericea! I don't recall how many flowers on each species I had pollinated, but some had indeed worked. Sixty-seven days later, I harvested the seedpods from P. rosettifolia, and then about two weeks after that, the seedpods on P. sericea were harvested. There were seeds inside of all of them.

Eight months after sowing the seeds, the first seedling from the rosettifolia x sericea cross was on what had been the most vigourous seedling all along....that plant later was named P. 'Rosemary Platz' after a dear friend. That first year, the plant had five flowers, but the foliage was really nice, and it shaped up very nicely.

Petrocosmea 'Rosemary Platz' in it's third season of a mature plant. It has exceeded my hopes and represents three qualities that have now become standards that I select for in all of my Petrocosmea hybrids.....floriferousness, reluctance to form offsets, and attractive, ornamental foliage.

A mature plant of P. 'Rosemary Platz' just coming into flower. This hybrid has attractive foliage, showing the glossiness and lighter yellow veining of it's P. rosettifolia #3 parent. It gets it's leaf shape and size from it's P. sericea parent. An additional plus is that after three seasons of bloom, the original plant has never yet formed a single offset...a trait that I select for in my hybrids. The tendency to offset at flowering ruins many showplants...and is a nasty trait of the P. rosettifolia species used as a parent. P. rosettifolia #3 is the form with yellow veining that is least likely to offset. Form #4 offsets very heavily and is the form of this species that, for me, is the most reluctant to flower. By chance, I used form #3 in this cross.....that was purely an "accident"...but was a happy "accident".

My friend and hybridizing mentor, Dale Martens, took this photograph of a dissected flower of P. 'Rosemary Platz'. This photo shows the attractive purple stigma at the tip of the pistil, and the feathery white furriness of the filaments supporting the anthers.... both traits that neither of this hybrid's parents have. SO where did these traits come from???? ("Thank you" Dale, for allowing me to use your photograph!)
As my third year of Petrocosmea hybridizing comes to a close, I've been very happy with my first hybrid. I've been delighted at the response I've gotten from Petrocosmea growers and gesneriad enthusiasts in general about this hybrid and I hope that it will become a welcomed addition to the world of gesneriad hybrids. This year, I've attempted to take things to the next generation, as I've begun using P. 'Rosemary Platz' and it's siblings, as parents in new crosses. They are now forming seedpods....indications that they may be both pollen and seedpod fertile. I'm excitedly looking forward to the future to see how my "child" behaves as a "parent".

Monday, December 21, 2009

The Winter Solstice

Today marks the Winter Solstice in the Northern Hemisphere. That means that beginning tomorrow, the days will grow longer. Even though I grow my Petrocosmeas primarily in a basement room with no windows, and the lights are timed the same year round, the plants always have a way of sensing this natural cycle. It always amazes me that they know, but somehow they do.

Some species of Petrocosmea have an annual growth cycle that involves what I have come to term a "semi-dormancy". Right after the autumn and winter flowering period, the plants begin to decline. The outer leaves begin to yellow and will eventually wither. In the center of the plant, the crown of new leaves become thickened and tight...almost as if the plants have an infestation of cyclamen mites. They don't. This cycle repeats every year for some species, and they always burst into rapid, lush growth each spring. The species that exhibit this pattern of growth, for me, are: P. nervosa, P. sp. 'vittatae', P. barbata, P. formosa, P. flaccida, and P. rosettifolia forms #1 and #2. Some hybrids involving these species in their parentage will also show a modified "semi-dormancy". The hybrids exhibiting this modified semi-dormancy are: P. 'Momo', P. 'Asa Blue', P. 'Imperial Butterflies', P. 'Short'nin' Bread', and P. 'Fluffer Nutter'.

One of my two mature plants of P. sp. 'vittatae' after a heavy flowering period. I allow the plant to dry out more between waterings and keep the plant cool. I will groom the dead leaves and flower peduncles off the plant, and will not fertilize it again until I begin to see new growth from the tight silvery center crown of the plant next spring.

The tight, silvery crown of P. sp. 'vittatae' as it retreats into it's annual semi-dormancy. I allow the plant to 'rest' until this center crown begins to expand with lush new growth next spring.

A mature plant of P. barbata 'Keystone'. This plant has been a workhorse of bloom all summer and was the parent of two hybrid crosses when it produced seven full seedpods. It's is deserving of a winter rest. Note how the outer leaves are beginning to yellow. The center crown is taking on the tight, gnarled appearance of it's semi-dormancy. This plant is NOT dying, but resting. Allow it to stay cool, drier, and give it no fertilizer over it's rest. When the new growth begins to emerge next spring, it will make rapid, lush growth. By keeping the roots drier, you avoid rot and root loss. This preserves that large, mature root system, which will support a large, full head of leaves next season. This large rosette of leaves, will nourish a heavy bud and bloom set next season.

The tight, silvery center crown of a P. barbata that is entering it's annual semi-dormancy. The plant is not dying, merely resting.
As the Petrocosmeas wind down from a heavy season of bloom and enter this annual semi-dormancy, it is important to realize that they are not dying. This is a nature response to the changing seasons, shorter days and cooler temperatures of winter. The key to saving these plants is to recognize what is happening and to provide the proper care when this occurs. It is easy to rot the root system if watering is not adjusted. As the plant drops it's leaves, it requires much less water and nutrients to support life. Watering schedules should be adjusted to allow the plants to remain drier, with only enough water to support the very tiny center crown which remains. If done correctly, the mature rootmass will be preserved. This larger mass of roots, next spring, will support a much more lush, and rapid return to full growth. The rosette will be renewed in a shockingly rapid growth spurt. Once growth resumes, I remove any additional offsets or crowns and repot if needed. I DO NOT repot all plants. If a single crown remains and the plant is otherwise happy, I will simply remove the top quarter inch or so of soil and replenish it, add systemic pesticide granules and give the plant a weak fertilizer until new growth is well advanced. Then, I resume my normal care patterns.
Lastly, I will mention that plants grown on reserviors of fertilizer water using the wick watering method, and plants that are kept in a constantly warm environment may not experience this semi-dormancy as markedly as my plants. I attempt to grow my plants as close to what I think their natural habitat provides as possible, so I allow my plants to get quite cool, even cold by some people's standards. I also allow plants to dry out between watering and reduce fertilizers to the point that I am using only plain water for non-blooming plants at this time of year. This is why, I feel, my plants exhibit this pattern.

The Rosettifolia group - Part IV - Still One More!

In this post of the series on The P. rosettifolia Group from my collection, I will discuss the most reluctant to bloom of the four forms I grow. This form of P. rosettifolia is the one that I label #4 in my collection. It is most similar to form #3 in several ways, but is easily distinguished from form #3 when the two are compared side by side. This form has a tendency to form offsets more than any other form of the species. It's foliage can be the most ornamental, however it's reluctance to bloom and it's tendency to form offsets can make it a challenge to produce a beautiful, blooming plant of this form. In fact, this form never flowered at all for me last year. I had three mature, large plants in my collection and not one flower. They were all grown on the same shelf as the other three forms, all of which flowered heavily. This makes it unlikely that I will use it much in hybridizing. I maintain it in the collection for it's genetic diversity and scientific value.

The flowers of this form of P. rosettifolia have curled petals, deep green "hoods" formed by the upper lip of the corolla and a slight purplish blush to the lower petals.
The flowers of P. rosettifolia #4 have pistils that point upward, due to a curve at the midpoint of the pistil. All other forms of P. rosettifolia present the pistils horizontally and straight.

While the ligthing in this photo is too bright, one can still see the shape of the leaves of P. rosettifolia #4. In this form, the leaves have the attractive yellow central and lateral veining, however, the green is deeper, almost black with good lighting. Leaves are more narrow and the teeth along the margins are present only along the distal half of the leaf. The lower portion of the leaf at the base has smooth margins, without the teeth.

The pistil of the flowers of P. rosettifolia #4 has a curve at the midpoint. This causes the tip of the pistil to be pointed upright, looking almost like the horn of a unicorn emerging from the flowers. The pistil on the other three forms of P. rosettifolia in my collection have straight pistils, which present horizontally from the base of the flower.
The cymes of P. rosettifolia #4 have three bracts, as does form #3. Forms #1 and #2 have only two bracts. The bracts on form #4 are longer and more linear than those of the other three forms.

So there are at least four distinct forms of the species labeled P. rosettifolia in cultivation. I have also seen photos that may indicate there are still other forms of this species out there also. Each species has distinct morphological differences, and DNA testing done on the four forms in my collection does confirm that they are unique individuals within the same species. Judges should keep this in mind when judging this species, as the size and ornamental value of each form can be quite different, as can the propensity towards forming offsets. The amount of bloom for each form can also vary quite a bit.

I will likely be making a couple more posts in this series in the near future. As additional plants that I lump into this group come into flower, I'll review them. The "P. rosettifolia Group", so far, promises to be the largest grouping of individual clones of species and close relatives, that my, with time, be shown to be additional forms or varieties of this species. I place them all within this "group" due to morphological and DNA data. Admittedly, this is a group the I alone, have created, and more learned minds than mine may have different opinions on the subject. Still, other species being grown currently under other names, such as P. sp. 'Chinese #2' , sp. 'China 2005', and the species 'Yumebutai' are the current focus of some study in an attempt to identify proper placement of these individuals within the genus.

Wednesday, December 9, 2009

Looking Back and Looking Ahead... Hybridizing Petrocosmea

If you will allow me to deviate from the thread on P. rosettifolia and it's variations, I had to take a few minutes to update you on the seedlings that are flowering now from last year's crosses and the seedpods that are forming on this years new crosses.

With the year 2009 quickly winding down to it's end, I had to take time today to go back and take another long, careful look at the batches of seedlings that are still flowering in the basement plant room. I've spent the entire year nurturing these precious little plants as they went from seedpod to flowering plants. What great fun this journey has been. I've been priveleged to see some seedlings that no one else has seen and evaluated. That's one of the exciting things about hybridizing in general and hybridizing a largely unexplored genus such as Petrocosmea in particular. I've filled my lightstands, my notebooks, my computer (with notes and photographs) and my trashcan as these seedlings matured, some to reveal "keepers" and some to reveal plants that lacked anything new, attractive, novel, or better than the parents. It is a heartbreaking task, to destroy a seedling that is the result of one's own efforts, but it must be done, and I'm proud to say, I've done it. In the end, I've selected some exciting and promising new hybrids for further evaluation.

I'm enjoying the results of two crosses that are now reaching the peak of bloom. The seedlings are the results of crosses between P. sericea x P. minor veined leaf form, and P. forrestii x duclouxii. Both of these crosses have produced variation in both foliage and flowers.

I've snapped some photos this evening of three of the most desireable from the P. sericea x minor seedlings. Foliage on these three is pretty much intermediate between both parents, but the flowers are showing some nice variation in size and coloration.

Three seedlings I'm keeping for further evaluation from a cross between P. sericea x minor veined leaf form. Note in the photo the variations in color of the petals, and the markings in the throat. The seedling in the middle has a clear demarcation between the clear white throat and the medium purple petals. All three flowers have a deep blackish purple dot in the base of the throat. The one on the right is a dark bluish purple, which the camera did not capture accurately. It is darker and more blue than the photo shows. Also note the large leafy bracts on the flower on the right, compared to the tiny bracts on the other two...this is consistent on all peduncles on this seedlings.

This seedling, the one on the right in the first photo, was the only seedling out of twenty to develop large leafy bracts on the peduncle. The hairs on the calyx lobes are also denser and longer than on other seedlings. It's color is the darkest of all of the seedlings in the batch although this photo makes the flower look much lighter in color than it really is.

This seedling has flowers with a clear, clean white throat that is nicely demarcated from the purple in the petals.

The flower on this seedlings is the largest of the batch of seedlings, and consistently has six petals while most of the other seedlings have five. Peduncles are nice and dark in color and are strong enough to support the large flowers. Bud and bloom count was also high for the parentage of the cross. Both parents are not usually heavy bloomers.

The second cross in flower now is P. forrestii x duclouxii. I have selected two seedlings so far, one of which I have named P. 'Keystone's Angora' due to it's soft, silvery furry leaves...the softest of any Petrocosmea that I have in my collection! Of the three seedlings selected, two have been in flower for a couple of months now and are continuing to produce buds...which bodes well for the flower count. The flowers of these two are quite different in size and show a variation in flower shape each taking after a different parent. See the photo below....
Flowers from two selected seedlings from a cross between P. forrestii and P. duclouxii. The flowers are quite different from each other in size. The flower on the left is from an as yet unnamed seedling that is taking it's plant/leaf size and flower shape and size from the P. duclouxii parent. The flower on the right is from a seedling named P. 'Keystone's Angora'. It's flower size and shape is more like it's P. forrestii parent, although both flower size and plant size is larger than P. forrestii. I attempted to pollinate the flower of P. 'Keystone's Angora' with pollen from P. begoniifolia and have several seedpods. You can see inside the throat of the flower in this photo that a small green seedpod is beginning to enlarge....indicating that it may indeed be fertile as a seed parent. Neither flower produces pollen so cannot be used for further breeding as a pollen parent.
While looking back at the past year's successes and failures is fun, rewarding and educational, I am also quite excited to see many seedpods forming on crosses I've made this flowering season. I noted seedpods forming this evening on the following crosses:
P. forrestii x formosa
P. rosettifolia #3 x minor veined leaf form
P. menglianensis x begoniifolia
P. 'Keystone's Angora' x begoniifolia and
P. 'Rosemary Platz' x (Asa Blue x begoniifolia)
I am transplanting small seedlings from crosses of P. forrestii x minor smooth leaf form and P. forrestii x sericea.
With all of these new crosses forming seedpods, and more plants still to bloom, there are still many exciting possibilities still ahead for the year to come. Wish me luck!

The Rosettifolia group - Part III - Yet Another One!

Certainly my favorite in the "Rosettifolia Group" is this species, P. sp. 'China 2005' The flowers are a lovely purple and the plant is literally loaded with buds and flowers. Easily the most floriferous species of the grouping.

A photo of one of my three plants of P. sp. 'China 2005' just coming into flower this week. This plant is three years old. Maturity of at least three years on Petrocosmea plants is proving to be a factor in heavy bloomset. Most Petrocosmea seen in shows, I suspect, are less mature at one to two years, and therefore often don't show a heavy display of bloom.
Here is yet another plant which I feel based on both morphology and DNA studies,belongs in the the "Rosettifolia Group". It is either another clone of the plants currently labeled P. rosettifolia in the USA, or at the very least, is a close relative or variety of that species. This plant was imported, by myself, as a wild collected plant in the year 2005. In the catalog from which it was purchased, it was labeled P. forrestii... it clearly is not. It shows no similarities with that species. In morphology, it is most similar to the P. rosettifolias, however neither it, nor any of the other plants currently labeled P. rosettifolia match the published description of P. rosettifolia in the Flora of China. AAahh, yes, yet another identification issue with our beloved genus Petrocosmea!
Recent DNA work is showing that P. sp. 'China 2005' is very closely related to the Rosettifolia grouping of species. It may turn out to be another clone of that species, (whatever it is) or at least a variety of that species. The only morphological difference that I can see is that the corolla color is deep purple, whereas the corollas on the other individuals in this grouping are white to very pale lavendar at best. The flower structure and plant structure and habit all match, however. This bloom cycle, I hope to try crossing it with my P. rosettifolias to see if they cross with each other.

The leaves of this species are plain, deep green and have a rough texture due to the short hairs. Leaf size, shape and plant size and habit all very closely resemble P. rosettifolia #1 and #2. This form is a very heavy bloomer...producing waves of buds over a period of four to five months in my conditions. Flowers are a lovely deep purple with a striking, purest white throat, which is slightly green at the very base of the tube. Petals most always number five...two up and three down, with the upper petals fused and bending forward to form a green "hood" as all of the other P. rosettifolias do. The flower morphology places the plant in Section - Anisochilus of the genus.

I have distributed leaves to a number of Petrocosmea growers over the past four years, and hope that this species will get into wider cultivation. It is a lovely plant in flower, and deserves a safe place in cultivation. Since it's place of collection is not known, and with the rate of destruction of habitat in China, it is a constant fear that this species and other plant species will be or may already be lost to nature forever. Keeping them alive in our collections and our hearts and hands is one way to ensure that they continue to amaze and delight us and future generations for years to come.

In bloom, this is one of my most favorite of all Petrocosmeas! Really! The masses of violet purple flowers on wiry peduncles are a lovely, charming gift each December, and they often last four or five months in my basement growing area. No other species has flowers this small and of this shape and color. Most others with this size and shape of flower have pale lavendar or white flowers, so this species is unique in that regard. Out of flower, however, this species is admittedly a bit lackluster in appearance.

Compare the form of this species with that of P. rosettifolia #1 and #2, and perhaps even P. menglianensis in my previous posts. It is hard to tell them apart. The key difference, for me, is that the leaves of this species feel "rough" when compared to those of the other species. Very "sandpaper-like" in texture.

One of the features of this species, which in my opinion detracts, is it's pesky tendency to form offsets when mature. Maturity brings a very heavy budset and flower count, but with the nuisance of offsets which spoil the flat, symmetrical shape of the plant's rosette, which it has to perfection as a younger plant. As can be seen here, even the offset if putting up a few buds.... This little species just loves to bloom!

So, to recap this thread of posts, so far, we have P. menglianensis, P. rosettifolia #1, P. rosettifolia #2, P. rosettifolia #3, and now P. sp. 'China 2005'. There are still others to come! While these plants as labeled, are called by various names at present, they may all turn out to be mislabeled. That is why I refrained from applying a species name to the species covered in today's post, and chose instead to just call it P. sp. 'China 2005'. Such labeling will indicate it's genus, place of origin and the year it was collected.